NY612
Disinfestation protocols for equipment
used in the nursery industry
Martin Mebalds, Wayne Tregea and
Andrea van der Linden
Agriculture Victoria
NY612
This report is published by the Horticultural Research and
Development Corporation to pass on information concerning
horticultural research and development undertaken for the
nursery industry.
The research contained in this report was funded by the
Horticultural Research and Development with the support of
the nursery industry.
All expressions of opinion are not to be regarded as expressing
the opinion of the Horticultural Research and Development
Corporation or any authority of the Australian Government.
The Corporation and the Australian Government accept no
responsibility for any of the opinions or the accuracy of the
information contained in this report and readers should rely
upon their own enquiries in making decisions concerning their
own interests.
Cover price: $20.00
HRDC ISBN 1 86423 675 2
Published and distributed by:
Horticultural Research & Development Corporation
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Gordon NSW 2072
Telephone:
(02) 9418 2200
Fax:
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E-Mail:
[email protected]
© Copyright 1997
v
HRDC
HORTICULTURAL
RESEARCH &
DEVELOPMENT
CORPORATION
Partnership in
horticulture
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
INDUSTRY AND TECHNICAL SUMMARY
A review of the literature on the efficacy of surface disinfestation protocols was instigated to address concerns
by the nursery industry that there was little specific information available on the efficacy of common
disinfestation protocols for plant pathogens, algae, mosses and lichen. A closely related issue of copper
contamination of nursery runoff water, caused by application of copper compounds for the control of
pathogens, algae, moss and lichen, was addressed and removal of copper from water was reviewed.
The review showed that many widely accepted chemical disinfectants do not kill or inactivate plant pathogens
from every biological group nor were they equally effective on all surfaces. For example, iodine, sodium
hypochlorite and quaternary ammonium compounds were found to effectively control a range of fungal
pathogens on pot surfaces but not on peat colonised by those pathogens. Similarly, quaternary ammonium
chloride formulations may effectively control fungal and bacterial pathogens but do not fully inactivate
viruses. All disinfectants required extended contact times for disinfestation, therefore rapid disinfestation for
'quick dip' procedures such as use of foot baths and disinfestation of pots, trays knives and shears need further
development. A summary of the efficacy of each chemical group is presented here and in Appendix 2.
Ethanol failed to control Tomato Mosaic Virus (ToMV), Cymbidium Mosaic virus (CyMV), Ondontoglossum
Ringspot Virus (ORSV) and Citrus Exocortis Viroid (CEV) on pruning tools and knife blades (Pategas et al.
1989, Hu et al. 1994 and Roistacher et al. 1969) or control CEV after dipping contaminated tools in 95%
ethanol followed by flaming. Similarly, Erwinia amylovora on contaminated shears survived a 10 min, but not
a 20 min dip in 70% ethanol. Erwinia amylovora however, was controlled with a 15 second dip followed by
flaming (Hasler et al. 1996). The practice of flaming however may be a serious safety hazard, especially, in
daylight where it is very difficult to detect the flame produced by burning ethanol. There is little evidence on
the effect of ethanol on plant pathogenic fungal spores contaminating nursery surfaces.
The use of phenol based compounds such as Physan®, Panacide® and Biogram® for the control of plant
pathogens needs further development as Physan did not control CYMV or ORSV on pruning tools (Hu et al.
1994); Biogram® failed to control Phytophthora cinnamomi on Banksia leaves (Noske and Shearer, 1989) and
Panacide® failed to control Thielaviopsis basicola in sand (O'Neill 1995). A phenol based product, Amocid®,
showed good in vitro effectiveness against a wide variety of pathogens including Fusarium oxysporum,
Didymella lycopersici, Phytophthora nicotianae and Clavibacter michiganense, however, the efficacy of the
product has not been demonstrated on nursery surfaces (Vanachter et al. 1991).
A quaternary ammonium compound, MENNO Ter Super®, has been shown to be effective against plant
pathogenic fungi (T. basicola and Cylindrocladium sp.) contaminating a range of nursery surfaces (Voss and
Meier 1987) but the product is not available in Australia and details of the compound which could identify
similar quaternary ammonium compounds were not reported. Other quaternary ammonium compounds have
shown incomplete control against T. basicola, P. cinnamomi, CyMV and ORSV (Copes and Hendrix 1996;
Noske and Shearer 1989 and Hu et al. 1994).
Sodium hypochlorite has been shown to be effective against a wide range of pathogens; CyMV at 2% a.i. and
ORSV at 15 a.i. (Hu et al. 1994), CEV on budding knives was inactivates at 0.26% a.i. / 1 sec (Roichester et
al. 1969), but failed to control ToMV on shears at 0.26% a.i. (Pategas et al. 1989). In peat debris colonised by
plant pathogenic fungi, sodium hypochlorite failed to control Verticillium dahliae or Phomopsis sclerotiodes at
10% a.i./60 min or Didymella bryoniae at 10% a.i./lO min (Avikainen et al 1993). Similarly, 1% a.i. sodium
hypochlorite /20 min failed to control Erwinia carotovora on wood, metal or plastic and failed to control
Clavibacter michiganense on metal or plastic (Koponen et al. 1992).
The recent literature therefore shows that there is insufficient knowledge on the efficacy of disinfectants
commonly used in nurseries to provide reliable guidelines for the adequate control of plant pathogens
contaminating propagating and cutting tools, nursery benches, paths and other surfaces
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
The control of algae, moss and lichen in nurseries was found to be based on copper compounds or herbicides
which are now out of date. Many chemicals have been tested as algicides but their effectiveness and
usefulness in the Australian nursery industry is unknown (Bodman 1996). The choice of algicides is made
difficult by conflicting reports of efficacy, the use of algicides in situations apart from nurseries and lack of
information in some reports. There has been extensive research on the control of moss and liverworts on
ornamentals. It is evident, however, that there are many areas that still need to be covered in greater detail. A
majority of the literature is lacking in specific information on the efficacy of cultural or chemical control
methods on mosses and liverworts in the plant nursery. The literature has presented a wide range of chemical
rates for moss and weedcontrol, however, the results of these were often contradictory. Future research should
identify the efficacy of control methods, identify appropriate chemicals and application rates for use in
Australia. Current information on the control of algae, mosses and liverworts will benefit the horticultural
industry with increases in plant quality, production, reductions in costs, and clean, hygienic nurseries.
Copper containing compounds are regularly used in the nursery industry for the control of fungal and bacterial
diseases, algae and mosses. Nurseries run the risk of excess copper on run-off in irrigation water, causing
toxicity to plants, or excess copper in water discharge may cause legal action against the nursery by the state
Environmental Protection Agency. An earlier study (NY320) however, found that this is an infrequent
occurrence. A review of methods for removal of copper from water identified a number of methods that could
be adopted by the nursery industry. Adsorption of copper to carboxy groups on organic matter indicates that
use of either peat, cation exchange resins, bark or algal biomass may be suitable for the removal of copper
cations from water.
Recommendations
•
A research program is required to assess the effectiveness of commonly used disinfectants from a wide
range of chemical groups for the control of representative virus, bacteria and fungal pathogens of nursery
plants.
•
The efficacy of disinfectants varies with type of surface and the degree of surface contamination. A
research program on surface disinfestation should include a range of materials found in nurseries.
Common surfaces include glass, steel, plastic, concrete, fibre cement, gravel, capillary matting and sand
beds.
•
Where containers, pots, trays, benches and equipment are being re-used, surfaces should be thoroughly
cleaned and free of residual organic matter and media prior to disinfestation treatments.
•
Unlike chemical disinfectants, heat adversely affects the viability of all pathogen groups and should be
used in preference to chemical disinfestation methods where practical.
A cknowledgements
The authors would like to thank the Nursery Industry Association of Australia and the Horticultural Research
and Development Corporation for financial support for the project. We would also like to thank Mr Hans
Kosmer, Nursery Industry Development Officer, Victoria, who had the original idea for the project and for his
input into the the project's development. We would also like to thank Mr Richard Wall who gave us
information on the impact of algae in nurseries and his methods for control.
11
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
CONTENTS
INDUSTRY AND TECHNICAL SUMMARY
Recommendations
Acknowledgements
CONTENTS
Abbreviations used in this publication
v
SURFACE DISINFESTATION OF PLANT PATHOGENS FOR THE NURSERY
INDUSTRY - A REVIEW
1
INTRODUCTION
References
1
3
CHAPTER 1
5
SURFACE DISINFESTATION OF PLANT PATHOGENS
1.1 Introduction
1.2 Hygiene methods in the horticulture industry
1.3 Current hygiene practices
1.4 Hygiene practices in other industries
1.5 Chemicals available in Australia
1.6 Current best control methods
1.7 Summary
1.8 References
5
5
6
8
14
18
19
20
20
CHAPTER 2 ALGAE
2.1 Introduction
2.1.2 Species
2.2 Climate and Environmental Conditions.
2.3 Control Methods
2.5 Concluding remarks on algae.
2.6 References
27
27
27
28
28
34
35
CHAPTER 3 MOSSES AND LIVERWORTS
3.1 Introduction
3.2 Control methods
3.3 Chemicals available in Australia
3.4 Summary
3.5 References
38
38
39
44
44
45
CHAPTER 4 REMOVAL OF COPPER FROM WATER
4.1 Introduction
4.2 Methods for the removal of copper from water
4.4 References
48
48
48
49
Appendix
Appendix 1. The algae reported growing on surfaces associated with man-made structures.
Appendix 2 Table of the efficacy of disinfectants on a range of plant pathogens
51
51
54
in
Surface D is infestation of Plant Pathogens for the Nursery Industry
NY 612
TABLES
Table 1.1 Pathogens identified as causing problems in the nursery.
Table 1.2 Information on the effective control of viruses in the nursery.
Table 1.3 Information on the control of fungi in the nursery.
Table 1.4 Information on the control of bacteria in the nursery.
Table 1.5 Hospital disinfectants
Table 1.6 Information on chemicals used for hygiene purposes
Table 1.7 Chemicals registered for general use on ornamentals in Australia
Table 2.1. Reviews of interactions of pesticides on algae as non-target organisms.
Table 2.2 Registered algicides in Australia.
Table 3.1 Species of moss and liverwort colonising ornamental plants and turf.
Table 3.2 Chemicals registered in Australia for use on moss
Table 4.1 Guidelines to the safe and legal levels of copper in water
iv
7
10
11
12
16
17
18
31
33
38
44
48
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Abbreviations used in this publication
ACH
a.i.
ARRIP data base
aq.
°C
CEV
cm
Cu2+
CyMV
DPI
EPA
et al.
g
H202
HOC1
hr
kHz
L
MHz
mg
mm
NaOCl
Na 3 P0 4
NIAA
NIASA
ocr
ORSV
pers. comm.
ppm
PSTV
QAC
sec
TMV
ToMV
U.C.
v/v
W
wp
Australian Horticultural Corporation
active ingredient
Australian Rural Research In Progress data base
aqueous
degrees Celsius
Citrus Exocortis Viroid
centimetre
Cupric ion
Cymbidium Mosaic Virus
Department of Primary Industries
Environment Protection Authority
et alii (and others)
gram
hydrogen peroxide
hypochlorous acid
hour
kiloHertz
litre
megaHertz
milligram
millimetre
sodium hypochlorite
Sodium triphosphate
Nursery Industry Association of Australia
Nursery Industry Accreditation Scheme, Australia
hypochlorite ion
Odontoglossum Ringspot Virus
personal communication
parts per million (1 ppm = 1 milligram/ litre or 1 milligram/kilogram
1,000 ppm = 1 gram/litre or 1 gram/kilogram, or a concentration of 0.1%)
Potato Spindle Tuber Viroid
Quaternary Ammonium Compound
second
Tobacco mosaic Virus
Tomato Mosaic Virus
University of California
volume per volume
Watt
wettable powder
v
Surface Disinfestation of Plant Pathogens for the Nursery Industry
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SURFACE DISINFESTATION OF PLANT PATHOGENS FOR THE
NURSERY INDUSTRY - A REVIEW
INTRODUCTION
The nursery industry has established an accreditation scheme called The Nursery Industry Accreditation
Scheme, Australia (NIASA) which prescribes guidelines for crop hygiene, regulatory requirements, crop
management practices and site appearance. Hygiene procedures should ensure that plants or media coming
into contact with various surfaces within the nursery are not contaminated with viruses, propagules of
bacteria, fungi, nematodes, algae, moss or liverworts, thereby, limiting the spread or organisms which reduce
plant production, plant quality and ultimately nursery profitability.
NIASA is deficient in that the current protocols are not effective in killing the most resistant pathogen
propagules such as bacteria and viruses in plant sap, fungal conidia, chlamydospores, oospores, cysts
sclerotia, spore-balls, nematode eggs, algae and weed seeds. All can cause significant economic losses if not
inactivated or killed. For example, sodium hypochlorite and quaternary ammonium compounds are
recommended as disinfectants for tools (NIAA/AHC 1994) but are not completely effective in the
disinfestation of Erwinia amylovora from pruning shears (Kleinhempel et al. 1987) or in the inactivation of
virus particles from pruning tools (Hu et al. 1994).
A review of the nursery hygiene protocols by Jarvis (1992) suggested a number of protocols for disinfestation
of tools, clothing and equipment that generally relied on the use of chlorine (as hypochlorous acid) or
trisodium phosphate. However, Jarvis made no specific recommendations on disinfectant concentrations or
minimum contact times required for disinfestation. Similarly, Goss (1983) suggested the use of 2 percent
hypochlorite, 2 percent formalin, methylated spirit, Biogram®, Hibitane® or Dettol® for disinfestation of
surfaces such as pots, paths, secateurs or pruning knives without indicating minimum contact times for
effective pathogen control. The Cornell Cooperative Extension (1995) recommended sodium hypochlorite
for the disinfestation of benches and equipment at 0.5% available chlorine for 10 minutes. Ammonium
chloride was also recommended as a disinfectant on hard surfaces for the control of fungi, bacteria and algae.
Similarly, NIASA (NIAA/AHC 1994) recommended chlorine or quaternary ammonium chlorides but gave no
concentrations or contact times required for disinfestation.
A study on surface disinfestation of pruning tools by Kleinhempel et al. (1987) examined the efficacy of 11
surface disinfectants including 5% sodium hypochlorite and 5% quaternary ammonium compounds against
the fire blight bacterium Erwinia amylovora. They found that none gave adequate disinfestation on pruning
tools which had cracks in their surfaces. If shears were plastic coated however, sodium hypochlorite or
quaternary ammonium compound reduced fire blight transmission to 4 and 35% respectively of that caused
by untreated shears.
Greenhouse and concrete surfaces are rarely included in studies on nursery hygiene yet they harbour
significant levels of pathogen inoculum. For example, 1,200 propagules of Fusarium oxysporum f.sp. dianthi
were detected in lg of soil collected from concrete floors in a glasshouse. This level of contamination poses a
serious disease risk (Ebben and Spencer 1976). Tomlinson et al. (1981) suggested that concrete and
glasshouse surfaces may be disinfected with 1% v/v (aq) Iodel®, an iodophor, but based their
recommendation on spore kill of Olpidium brassicae resting spores after exposure to the disinfectant in
solution. Other work however suggested that disinfectants were less effective on surfaces than in liquids
(Kleinhempel et al. 1987), indicating that surface disinfestation studies are required for the adoption of
appropriate disinfestation protocols.
Research on the disinfestation of seeds (Sauer and Burroughs 1986) and other produce (Beuchat 1992; Martin
and Torres 1989) indicated that the efficacy of disinfestation of plant pathogens from organic surfaces is
affected by the presence of cracks, air bubbles and surface debris. The results indicated the importance of
surface texture and composition on the efficacy of disinfestation practices for hard surfaces. Disinfestation of
Tomato Mosaic Virus (ToMV) on pruning shears was found to be most effective when shears were dipped
for 5-10 sec in 10% trisodium phosphate; treated shears transmitted ToMV to 3% of plants whilst untreated
shears transmitted the virus to 70% of plants (Pategas et al. 1989). In the same experiment, dipping shears in
70% ethanol and 0.26% sodium hypochlorite resulted in 71% and 22% transmission respectively.
1
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Importantly, none of the disinfestation procedures evaluated in these experiments reduced disease spread to
below 1% of control. There is a need therefore to determine more effective disinfestation practices for the
control of bacteria and viruses adhering to equipment surfaces.
Substantial work on disinfestation of surfaces is done in the food and dairy industries where human pathogens
are studied. These findings are not directly applicable to nursery hygiene. The work however, gives valuable
information on methodology and on the comparative resistance of bacteria in solutions and when attached to
surfaces (eg. Holah et al. 1990; Cerf 1986). They found that organisms adhering to surfaces are generally
more resistant to disinfectants than organisms suspended in water.
Algae are a major problem in nurseries. Growth of algae on pots, growing media surfaces and plants for sale
is unsightly and reduces water penetration. On floors it is slippery and dangerous to staff and on benches and
other surfaces it acts as a refuge for pests and diseases. On greenhouse surfaces, it reduces light levels,
thereby reducing plant growth. Common practices for the control of algae include the use of copper based
chemicals which can become a major pollutant of ground and water (James and Beardsell 1995). An
alternative to copper for the control of algae, bromochlorodimethylhydantoin (Agribrom®, Nylate®) was
shown to be effective in controlling algae in subirrigation mats at 4-5 ppm however it slightly suppressed root
development (Tayama et al. 1986). In Europe, quinonamid was found to control algae and moss in
greenhouses and in outdoor bedding plant crops. Delegol was recommended as a dip to disinfect pots of
algae (Hemer 1980). This product however, is not registered in Australia for use in nurseries and extensive
field data may be required for local registration.
Mosses and liverworts in nurseries tend to colonise the drainage holes and surface soil of potted ornamentals.
This interferes with drainage and water movement in the pots. Mosses and liverworts make the nursery look
untidy and provide a shelter for pests (Goss 1983). Tenoran® was commonly used for control, however, it
has not been available since 1991. Copper has also been used to effectively control mosses and liverworts
(Montoya et al. 1972) and for the control of algae in water storages, reducing filter blockages and chlorine
demand. Copper however, is undesirable for the reasons outlined above. A recent survey has shown that on
at least one occasion throughout the year, approximately one in thirty nurseries will exceed EPA limits for
copper in discharge water and safe limits for plant growth (James and Beardsell 1995).
Removal of copper from recycled nursery water may be achieved by reaction with bark or lignin (Jodai et al.
1978; Varma et al. 1989; Viraraghavan and Dronamraju 1993), perhaps by using waste potting mix or bark.
however, copper contaminated material would need disposal. There remains a possibility that copper may be
absorbed on bark/sawdust/peat based media in pots, where copper is often deficient or at low levels (Bodman
pers. comm).
Currently there is no research in Australia on the disinfestation practices for nurseries (ARRIP database)
although a project on the biological suppression of fungal disease in container media by Dr P. Fahey
addressed some aspects of disease suppression (Moody 1996). There has also been some work on the
disinfestation of soils from Phytophthora spp. using chlorine, substituted phenols and quaternary ammonium
chlorides (Gerriste et al. 1992), however, results indicate lengthy contact times are required and hence would
be unsatisfactory for the routine disinfestation of many nursery surfaces. The review does not cover
disinfestation of water or seed as these topics are covered in recent Horticultural Research and Development
Corporation projects (James and Beardsell 1995; Mebalds et al 1996).
In recognition of the lack of accessible information on the efficacy of disinfectant protocols, the Nursery
Industry Association of Australia and the Horticultural Research and Development Corporation funded this
review. It summarises current knowledge on the effectiveness of physical and chemical hygiene procedures
for the disinfestation of surfaces commonly found within the nursery and aims to identify areas where
protocols are adequate and areas where further research is required.
The following literature review is divided into four chapters:
Chapter 1
Reviews general hygiene practices in the horticulture industry and also examines hygiene
methods in other industries,
Chapter 2 & 3
Reviews control of algae and mosses and liverworts in nursery situations,
2
NY 612
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Chapter 4
Investigates the use of copper in the horticulture industry, alternatives to copper and
methods for the removal of heavy metals from water.
References
ARRIP (1984 - August 1996) Australian Rural Research In Progress, Department of Natural Resources
Database, Infoscan Pty Ltd, Victoria.
Beuchat, L.R. (1992) Surface disinfection of raw produce. Dairy, Food and Environmental Sanitation. 12:
6-9.
Cerf, O. (1986) Knowledge of disinfection of equipment surfaces. Technique Laitaire and Marketing. 1005:
30-32.
Cornell Cooperative Extension (1995) 1995 Recommendations for the Integrated Management of Greenhouse
Florist Crops. New York, USA.
Ebben, M.H. and Spencer, D.M. (1976) Fusarium wilt of carnation, caused by Fusarium oxysporum f. sp.
dianthi. Annual Report of the Glasshouse Crops Research Institute, pp 113-115.
Gerriste, R.G., Adeney, J.A., Baird, G. and Colquhoun, I. (1992) The reaction of copper ions and
hypochlorite with minesite soils in relation to fungicidal activity. Australian Journal of Soil
Research 30: 723-735.
Goss, O.M. (1983) Practical Guidelines for Nursery Hygiene.
Paramatta, NSW.
Australian Nurseryman's Association,
Hemer, M. (1980) Algae and moss. Experiences and experiments on control. Gartenetl + Gw. 80: 53-54.
(Abstract only)
Holah, J.T., Higgs, C , Robinson, S., Worthington, D. and Spenceley, H. (1990) A conductance-based surface
disinfection test for food hygiene. Letters in Applied Microbiology 11: 255-259.
Hu. J.S., Ferreira, S., Xuu, Q., Lu, M., Iha, M., Pflum, E. and Wang, M. (1994) Transmission, movement,
and inactivation of Cymbidium Mosaic and Odontoglossum Ringspot Viruses. Plant Disease 78:
633-636.
James, E.A. and Beardsell, D.V. (1995) Final report on nursery recycled water Part 2: Water quality survey.
Recycling water in the Australian nursery and flower industries: managing water quality and
pathogen disinfestation. Final report for HRDC project No. NY320, Institute for Horticultural
Development, Knoxfield VIC.
Jarvis, W.R. (1992) Managing Diseases in Greenhouse Crops. The American Phytopathological Society
Press, Minnesota, USA.
Jodai, S., Onishi, FL, Uehara, T. and Goto, T. (1978) Studies on the adsorption of heavy metal by bark from
polluted water. 3 Removal of copper (II) from polluted river. Kenykyu Hokoku Bulletin of the
Faculty of Agriculture, Shimane University 12, 114-116.
Kleinhempel, H., Nachtigall, M., Ficke, W. and Erhig, F. (1987) Disinfection of pruning shears for the
prevention of fire blight. Acta Horticulturae 111: 211-218.
Martin, H. and Torres, H. (1989) Control of Rhizoctonia and other soil-borne diseases of TPS. Fungal
Diseases of Potato. Report of the Planning Conference on Fungal diseases of Potato. Peru, 1989. pp
191-205.
Mebalds, M.I., van der Linden, A., Hepworth, G. and Beardsell. D. (1996) Disinfection for recycled water
using ultraviolet light and chlorine dioxide. In Recycling Water in the Australian Nursery and
Flower Industries: Managing Water Quality and Pathogen Disinfestation. by James, E., Mebalds,
M.I., Beardsell, D., van der Linden, A. and Tregea, W. (1995) Final Report for HRDC Project No
NY320.
3
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Montoya, J., Dongo, S. and Osores, A. (1972) The control of mosses, algae and lichens on citrus in the
Chanchamayo Valley. Proceedings of the Tropical Region. American Society for Horticultural
Science 16.93-106.
Moody, H. (1996) Disease suppressive composts researched. Australian Horticulture 94(2): 36.
NIAA/AHC (1994) The Nursery Industry Accreditation Scheme, Australia.
Pategas, K.G., Schuerger, A.C. and Wetter, C. (1989) Management of Tomato Mosaic Virus in
hydroponically grown pepper {Capsicum annum). Plant Disease 73: 570-573.
Sauer, D.B. and Burroughs, R. (1986) Disinfection of seed surfaces with sodium hypochlorite,
Phytopathology 76: 745-747.
Tayama, H.K., Zrebiec, V. and Smith, R.E. (1986) A new biocide/disinfectant for the floricultural industry,
Ohio Florist's Association Bulletin 685: 1-3.
Tomlinson, J.A., Faithful, E.M. and Clay, CM. (1981) Big-vein disease of lettuce. National Vegetable
Research Station 31s' Annual Report 1980, Stratford-upon-Avon, UK, pp 82-83.
Varma, K.V.R., Swaminathan, T. and Subrahmanyam, P.V.R. (1989) Studies on copper removal by lignin
solution/suspension. Journal of Environmental Science and Health, Part A Environmental Science
Engineering 24: 847-861.
Viraraghavan, T. and Dronamraju, M.M. (1993) Removal of copper, nickel and zinc from wastewater by
adsorption using peat. Journal of Environmental Science Health A28: 1261-1276
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Surface Disinfestation of Plant Pathogens for the Nursery Industry
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CHAPTER 1
SURFACE DISINFESTATION OF PLANT PATHOGENS
1.1
Introduction
The nursery industry recognises the need for the production of high quality, disease free plants to ensure sales
in a highly competitive market. However, the often humid, protected environments found in nurseries are the
conditions favourable for initiation and spread of disease (Higgs 1978). In the field, the major sources of
spread are recognised as soil, air, water, insects and other diseased plants. In nurseries, spread of disease may
be aided by contact with contaminated surfaces such as clothing, benches, pruning, grafting and budding
knives, capillary mats, gravel beds, pots and trays, or from contaminated water recycling system components
such as tanks, pipes and sprinklers (Moody 1983). The industry has recognised that hygiene practices form a
significant role in the exclusion of disease from plant production areas and the control of disease spread when
plant pathogens are present (Higgs 1978; Goss 1978; Higgs 1981; Bunker 1990). Sound disinfection
protocols are essential to contain the spread of exotic diseases such as fire blight. A study of glasshouse
production of vegetable crops showed that insect and disease control strategies accounted for 16.5% of the
cost of production (Cabello and Canero 1994). Nursery hygiene is the key to a cost effective pest and disease
prevention program (Lisle 1986; Byther 1993) and is an efficient way of ensuring continuing plant quality
while minimising the use of agrochemicals, which in turn decreases environmental and workplace safety, and
phytotoxicity risks in nursery production. Improved hygiene techniques will be an essential tool when the all
purpose sterilant, methyl bromide is phased out.
A number of guidelines on hygiene for the nursery industry have been published. The European and
Mediterranean Plant Protection Organisation (1993) recommended a scheme outlining general nursery
requirements for establishments intending to propagate fruit or ornamental crops for certification. The 'Clean
Scheme' in South Australia addressed the spread of Phytophthora cinnamomi (Ranford 1979) and Goss
(1983) released a book on general nursery hygiene techniques. Baker's (1957) U.C. System for the
production of healthy container plants has been recognised as a basis for hygiene in many Australian
nurseries (Higgs 1978; Bunker 1990). The U.C. System recommendations were updated by McCain (1977)
but still make use of formalin for disinfestation of pots, footwear and equipment. Formalin however has been
found to be carcinogenic and is no longer considered safe to use. Cornell Cooperative Extension (1995) had
also published a set of guide lines for nursery hygiene practices. The guidelines however do not provide
specific information on disinfectant concentrations and contact times for adequate disinfestation of various
surfaces. Some recommendations are now out of date including the use of chemicals such as formalin (Goss
1983). The lack of recommended disinfectant concentrations and contact times indicates that, even when
following guidelines, infectious propagules may survive disinfestation treatments if concentrations or contact
times were inadequate. Information about disinfectant efficacy against plant pathogens needs to be collected
to improve current hygiene recommendations.
1.1.1 Sources of contamination
Hygiene practices in any situation or industry are aimed at restricting the movement of, and the destruction of
propagules of infectious agents (bacteria, virus, fungi, phytoplasma, nematodes, mites and insects) from
growing media, water, equipment, tools or any surfaces, including growing-on surfaces and capillary mats
before they come into contact with susceptible hosts.
Sources of contamination in the horticultural industry as identified by Moody (1983) are:
•
'Contaminated soil or potting mix splashed onto clean areas by drops of water from irrigation or rain
•
Pathogens deposited on cuttings when placed in contaminated water or hormone solutions
•
Hoses dropped carelessly to the ground where pathogens get into the nozzle-end and are expelled
into the pots or on benches at the next watering
5
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Pathogen-infested soil and organic material not removed from used flats, pots, or other containers
and benches prior to disinfestation
Contaminated soil carried on tools, covers, worker's hands
Sterile potting mix placed on benches or flats, contaminated greenhouse floors caused by foot traffic
Flats or plants placed on the ground
Planting infected seed, cuttings or seedlings.'
Other recorded sources of pathogen inoculum include:
Drainage and irrigation water
Placement on infested growing surfaces such as sand, capillary mats and ebb and flow trays
Dust contaminating paths, equipment and tools
Insects, nematodes and mites
Larger animals may carry bacterial of fungal inoculum from plant to plant
Contaminated clothing, gloves and footwear
1.2
Hygiene methods in the horticulture industry
1.2.1 Need for control
It is essential that sources of contamination in the nursery are identified, and control measures are taken to
reduce losses and costs. Bacteria, viruses, fungi, phytoplasma, nematodes and insects are found in many
locations in the nursery. Good hygiene is one of the basic requirements for the successful germination of
seed according to Heath (1985). Good hygiene ensures that propagation areas, propagation houses and
growing structures are clean, and that there is a sensible use of chemicals to prevent disease. Such practices
will keep crop losses to a minimum and therefore save on production costs. The occurrence of exotic
diseases such as fireblight in production areas has caused severe disruption to production and trade within the
nursery and for the whole state. Efficient hygiene protocols will limit the spread of such diseases.
Holmes and Litterick (1994) found Rhizoctonia in diseased stock plants, cuttings, nursery soil, used pots and
trays, capillary matting, benches and polythene, and used compost or compost containing unsterilized loam.
Losses due to transmission via contaminated pathways and equipment may be substantial but the economic
impact has not been quantified. Algal contamination of paths, ebb and flow systems and water contribute to
major maintenance costs where pipes and sprinklers require frequent cleaning. Algal growths on paths are
slippery and present a significant health and safety concern for nursery staff (R. Wall pers. comm.). Current
use of copper control creates a problem with excessive copper levels in runoff water in approximately one in
thirty nurseries (James and Beardsell 1995).
In addition to the sources of contamination as identified by Moody (1983), workers can spread pathogens,
algae and pests on their person. Hands, clothing and footwear have been known to transmit diseases
throughout nurseries. Tomato plants were found to be easily infected with Tomato Mosaic Virus (ToMV) by
contact with infected clothing (Broadbent and Fletcher 1963) and hands (Broadbent 1963). Dust found on
nursery paths has been found to carry 1,200 propagules of Fusarium oxysporum f.sp. dianthi (Ebben and
Spencer 1976). Blight on leatherleaf ferns caused by Colletotrichum was found to be transferred from plant
to plant via workers clothes, where spores of the fungus were found to survive and remain viable for 14 days
or more (Shaw 1996). Colletotrichum was reported as causing fern losses of 80% in some nurseries. It is
vital that hygiene is used in the control of this disease as there are no effective registered fungicides available
(Shaw 1996). Water and waste water are common sources of pathogens, especially where water is drawn
from near-by creeks which receive run-off from other nurseries in the area. In a small sample of water
sources around Melbourne, creek water and run-off water had propagules of Phytophthora, Fusarium, Phoma
and Alternaria species, all of which could be pathogenic to a wide range of plants in nurseries (Mebalds,
unpublished data).
6
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
1.2.2 Major diseases and mode of spread
Disease spread may occur via movement of contaminated plants or soil where healthy plants come into
contact with infected material. Many diseases occurring on above ground plant parts have dry spores on the
surface of infected plants and are spread when forcibly ejected into the air or dislodged by wind. The spores
are then carried along by air currents and land on plants which are often remote from the infected plants.
Other pathogens produce spores in slimy masses and require the action of water droplets or water streaming
along plant surfaces to carry them to new sites for infection. Splash dispersal occurs when a water droplet
lands on a leaf surface which then breaks up into smaller droplets and aerosols. If drops land on a spore mass
or bacterial colony, then bacteria or fungal spores are carried away in the droplets and aerosols. When tools,
pots or machinery come into contact with infected plants, they become contaminated with the organism.
Infected sap from plants often contaminates pruning shears and knives which are then difficult to sterilise
(Kleinhempel et al. 1987). The methods of spread of many of the common plant pathogens is summarised in
Table 1.1. Plants coming into contact with diseased plant material, trash, re-used media or debris is a
common method of disease spread and was not listed in the table as it applies to most diseases.
Table 1.1 Pathogens identified as causing problems in the nursery.
Pathogen*
common name
pathogen type
some methods of spread
Agrobacterium sp.
Albugo spp.
Allernaria spp.
Aphelenchoides fragariae
Apple Mosaic Virus
Bean Yellow Mosaic Virus
Bipolans sp.
Botrytis cmerea
Botrytis sp.
Brachybasidium pinangae
Carnation Mottle Virus
Ceratocystis
Cercospora sp
Cercosporidium sp.
Cerotelium sp.
Chalara elegans Chalara spp.
Chrysanthemum Stunt Viroid
Coleosporium sp.
Colletotrichum spp.
Cucumber Mosaic Virus
Curvularia spp.
Cylindrocladium sp.
Cymbidium Mosaic Virus
Dahlia Mosaic Virus
Dasheen Mosaic Virus
Dasturella divina
Dendryphion spp.
Drechslera spp.
Elsinoe sp.
Erwinia sp.
Exobasidium azalea
Fusarium oxysporum
Ganoderma lucidum
Gliocladium vermoseni
Glomerella sp.
Graphiola spp.
Hibiscus Chlorotic Ringspot Virus
Hippeastrum Mosaic Virus
Iris Mosaic Virus
Kentia Palm Mosaic
Meloidogyne sp.
Microsphaera sp.
Mycosphaerella spp.
Odontoglossum Ringspot
Oidium sp.
Orchid Fleck
crown gall
white blister
leaf spot
foliar nematode
bacteria
fungus
fungus
nematode
virus
v irus
fungus
fungus
fungus
fungus
virus
fungus
fungus
fungus
fungus
fungus
viroid
funaus
fungus
virus
fungus
fungus
virus
virus
virus
fungus
fungus
fungus
fungus
bacteria
fungus
fungus
fungus
fungus
fungus
fungus
virus
virus
virus
virus
nematode
fungus
fungus
virus
fungus
virus
Soil / Grafting knives
Water
Air / Seed
Soil / Water
Equipment / Insect
Equipment Seed Insect
Air / Seed
Air / Water / Splash / Soil / Seed / Insect
Air / Water / Splash / Soil / Seed/ Insect
Air / Soil
Equipment / Insect
Air / Insect/ Equipment/ Containers
Air / Equipment / Insects
Air/ Seed
Air
Soil / Peat / Containers / Equipment
Equipment / Insect
Air
Seed / Splash / Soil / Workers
Equipment / Insect / Seed / Recycled water
Air / Seed
Soil / Pots / Water
Equipment / Insect
Equipment / Insect
Equipment /' Insect
Air
Air / Seed
Air / Seed
Water / Splash
Soil / Equipment
Air
Equipment / Seed / Soil / Water
Soil
Soil / Splash
Seed/ Splash
Air
Equipment / Insect
Seed
Equipment / Insect
Equipment / Insect
Soil / Water / Hydroponic systems
Air
Air / Seed / Splash
Equipment
Air
Equipment / Insect
stem rot
petal blight
grey mould
leaf spot
black cane rot
leaf spot
leaf spot
rust
black root rot, root & rhizome rots
stunt
rust
leaf curl/root rot
conn rot/leaf spot
fungal leaf spot/root rot
stunt
rust
rot
blight
scab
bacterial blight
leaf gall
fusarium
root and trunk rot
stem rot
fungal leaf spot/dieback
false smut
root-knot nematode
powdery mildew
leaf spot
powdery mildew
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Pathogen*
Orchid Strain
Orchid Streak Virus
Ovulinia sp.
Pelargonium Leaf Curl Virus
Pelargonium Mosaic Virus
Peronospora spp.
Peslalotiopsis sp.
Phialophora cmerescens
Phoma spp.
Phomopsis sp.
Phragmidium sp.
Phyllosticla sp.
Phytophthora spp.
Pratylenchus spp.
Primus Necrotic Ringspot Ilavirus
Pseudocercospora
Pseudomonas spp.
Puccinia sp.
Pucciniastrum sp.
Pythium sp.
Radopholus similis
Ramidaria pitereka
Rhizoctonia spp.
Rhi/opus stolonifer
Rose Mosaic Virus
Roystonea Palm Potyvirus
Sclerotinia spp.
Sclerotium spp.
Septoria spp.
Sphaceloma sp.
Sphaerotheca spp.
Stagonospora sp.
Stemphylium spp.
Stigmina sp.
Stromatima gladioli
Stylinia spp.
Taphnna sp.
Tobacco Streak Virus
Tomato Big Bud Mycoplasma
Tomato Spotted Wilt Virus
Tranzchelia spp.
L'romyces spp.
L'romycladium spp.
Vstilago sp.
I'ertiallium spp.
Xanthomonas sp.
common name
petal blight
downy mildew
fungal leaf spot
phialophora wilt
leaf spots, stem spot
phomopsis rot
rust
fungal leaf spot
root rot. foliage rots
root lesion nematode
fungal leaf spot
bacterial leaf spot
rust
rust
root rot
burrowing nematode
ramularia blight
root rot
rhizopus rot
palm ringspot
stem rot
root rot
leaf spot
scab
powdery mildew
leaf scorch
ray speck, leaf spot
shotholc
stromatinia neck rot
false smut
leaf curl
tobacco streak
big bud
spotted wilt
rust
rust
gall rust
anther smut
verticillium wilt
bacterial leaf spot
NY 612
pathogen type
some methods of spread
virus
virus
fungus
virus
virus
fungus
fungus
fungus
fungus
fungus
fungus
fungus
fungus
nematode
virus
fungus
bacteria
fungus
fungus
fungus
nematode
fungus
fungus
fungus
virus
virus
fungus
fungus
fungus
fungus
fungus
fungus
fungus
fungus
fungus
fungus
fungus
virus
phytoplasma
virus
fungus
fungus
fungus
fungus
fungus
bacteria
Equipment / Insect
Equipment / Insect
Air/ Insect /Splash
Equipment / Insect
Equipment / Insect
Air
Splash / Seed
Not in Australia
Seed / Splash
Seed / Splash
Air
Seed/ Splash
Water / Equipment/ Soil / Grow-out beds
Soil / Water / Drainage water
Equipment / Seed / Insect
Water / Air
Water/ Seed/ Equipment
Air /Clothes
Air
Water / Equipment / Seed / Soil
Soil / Drainage water
Soil
Soil /Seed
Air / Seed
Equipment / Seed / Insect
Equipment / Insect
Air / Soil / Seed
Soil
Seed / Splash
Seed / Air / Splash
Air
Seed / Splash
Air / Seed
Air
Soil
Air
Equipment / Seed / Insect
Equipment / Insect
Equipment / Insect / Seed
Air
Air/Seed
Air
Air / Seed
Soil / Water / Seed
Equipment / Seed / Water
*Adaptedfrom Bodmanetal. 1996 and Richardson, 1990.
Insects such as fungus gnats have also been implicated in the spread of fungal pathogens such as Botrytis
cinerea (G. Stovold pers. comm.)
Seed is identified (Table 1.1) as an important source of fungal, bacterial and viral inoculum and effective seed
treatment for the control of pathogens is an integral part of nursery hygiene practices. Seed treatment for the
control of pathogens may be achieved using chemical treatments, hot water, a combination of chemical and
hot water or steam-air treatments (Richardson 1990, Minchinton 1994, Mebalds et al. 1996 and Maude 1996).
Often, chemical-only seed treatments do not effectively control seed-disease. When disinfectants were used
on cabbage seed to control Xanthomonas campestris, neither Agribrom®, Bronopol®, Chinosol® nor
Natriphene® eliminated the bacterial infection (Minchinton 1994).
1.3
Current hygiene practices
There are commonly accepted hygiene practices for growing media and water. The Nursery Industry
Accreditation Scheme, Australia (NIASA) (NIAA/AHC 1994) requires that contaminated water be treated
8
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
using one or several approved methods including chlorination, bromination, microfiltration, ozonation and
UV irradiation. Potting media is pasteurised with aerated steam or chemically treated with methyl bromide or
Basamid® (Baker 1957, Goss 1983, Bunker 1996). Soil solarisation is an alternative treatment in certain
conditions (NIAA/AHC 1994).
Chemical soil fumigants and organic soil fungicides have been used for the control of Phytophthora
cinnamomi. Fumigants such as methyl bromide and chloropicrin have been found to reduce spores in the
soil. Other chemicals such as the soil drench Terrazole at 50 ppm every month has been used as a
preventative to the introduction of P. cinnamomi. Metalaxyl (Ridomil 5G®) at a rate of 100 g/m has also
been used as an inhibitor of the disease (Alexander 1983). Development of resistance to metalaxyl by
Phytophthora spp. however results in a failure to control disease (Ferrin and Rohde 1992).
Hygiene in nurseries normally involves chemical treatment of surfaces contaminated by viruses, fungi and
bacteria. Chemicals vary widely in their applications and uses. Information on the chemical control of each
disease is given in the tables and discussion below.
1.3.1 Effective virus control
Many viruses are effectively inoculated into plants via cutting tools contaminated with plant sap (Hu et al.
1994) and virus particles may survive on steel blades for 8 days (Allen 1968). Disinfestation of cutting tools
is therefore critical to effective control of many plant viruses. Similarly, many plant viruses are spread by
insects such as aphids and leafhoppers. Control of virus spread in this case requires control of the insect
vectors and is not covered here.
1.3.1.1 Disinfestation of water and surfaces contaminated with wet, infected sap
Brock (1952) found that ethyl alcohol, formalin and trisodium phosphate (Na 3 P0 4 ) at concentrations less
than 5% v/v were ineffective in controlling Tobacco Mosaic Virus (TMV), however a 5 min contact time
with 5% Na 3 P0 4 was sufficient to inactivate the virus from water and from surfaces of mortar and pestle used
to crush infected plant tissue. Arabis Mosaic Virus was more susceptible than TMV to disinfectants, being
inactivated with 0.5% Na 3 P0 4 / 1 hr, 0.5% formaldehyde/ 30 min, 3% Orbiplant Special®/ 2hr and 0.5%
potassium permanganate/ 30 min. Tomato Mosaic Virus (ToMV) was controlled after exposure to 3%
Na 3 P0 4 / 5 min in solution or after 60 minutes when ToMV was present on a cut surface (Broadbent 1963).
Disinfestation of ToMV on pruning shears was found to be most effective when shears were dipped for 5-10
sec in 10% Na 3 P0 4 ; although treated shears resulted in 3% infected plants whilst untreated shears transmitted
the virus to 70% of plants (Pategas et al. 1989). In the same experiment, dipping shears in 70% ethanol or
0.26% sodium hypochlorite (NaOCl) resulted in 71% and 22% infected plants respectively. Sing et al.
(1989) contaminated cutting knives with Potato Spindle Tuber Viroid (PSTV) then dipped them for 5 sec in
solutions of Alcide LD®, Incyte® (products which generate chlorine dioxide) or sodium hypochlorite. All
disinfectants controlled the viroid on knives but only a 10 sec spray of 2-3% NaOCl solution effectively
controlled the viroid on other tissue processing equipment such as a rollerpress. When orchid leaves infected
with either Cymbidium Mosaic Virus (CyMV) or Odontoglossum Ringspot Virus (ORSV) were crushed and
diluted into various disinfecants, it was found that CyMV and ORSV were inactivated with 2% and 0.5%
NaOCl respectively or with 1% sodium hydroxide (Hu et al. 1994). Only 0.5% NaOCl resulted in phytotoxic
effects on orchid plants. In the same series of experiments, 20% Physan, Agribrom or liquid detergent failed
to control the viruses.
An extensive study of disinfestation of knife blades from Citrus Exocortis Virus (CEV) indicated that a one
second dip in either 0.26 - 1.05% sodium hydroxide or 2% formalin + 2% sodium hydroxide controlled virus
transmission while 95% ethanol or 95% ethanol + flame, -2% Na 3 P0 4 4 - 8 sec flame (propane torch), 10%
borax, 3% formalin or 20% Phisohex did not prevent transmission of the disease when the treated blades were
used to graft citrus plants (Roistacher et al. 1969). Garnsey and Jones (1967) had similar results for ethanol
and formalin + NaOH.
1.3.1.2 Disinfestation of surfaces contaminated with dry, infected sap
Marcussen and Meyer-Kahsnitz (1991) found that many chemicals labelled viricides had no or limited
efficacy on infected sap which had been dried onto a surface and that viruses differed in their susceptibility to
disinfectants. They found that 5% Na 3 P0 4 , 5% formaldehyde or 5% Orbiplant Special® (mixture of alcohol
and aldehyde) had no effect on TMV after 2 hours contact time. TMV however, was controlled with 0.5%
9
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
potassium permanganate/ 30 min. The results contrast with those of Brock (1952), Broadbent (1963) and
Pategas et al. (1989) who had achieved inactivation of virus in 5% Na 3 P0 4 in less time indicates the need for
extended contact times for adequate disinfestation of surfaces where infected sap has been allowed to dry.
1.3.1.3 Disinfestation of hands contaminated with wet, infected sap
Disinfestation of hands contaminated with plant virus was studied by Broadbent (1963) and Marcussen and
Meyer-Kahsnitz (1991). Washing hands with 3% Na 3 P0 4 followed by a wash with a detergent 'DAZ'
reduced hand transmitted ToMV lesions from 799 to 4 lesions (Broadbent 1963). The studies indicate that
TMV may be more resistant to Na 3 P0 4 than ToMV. ToMV was found to persist on clothing stored in a dark
enclosed space, but was inactivated within a few weeks in daylight (Broadbent and Fletcher 1963).
Table 1.2 Information on the effective control of viruses in the nursery.
Method of Transmission
Chemical
Rate
Reference
Surfaces, Hands
Tri-sodium phosphate
Formaldehyde
Potassium permanganate
0.5%/60 min
0.25%/60 min
0.25%/5 min
Marcussen and
MeyerKahsnitz 1991
Cucumber Green Mottle
Mosaic
Virus
(CGMMV)
Citrus Exocortis Virus
Tools, Sticks, Hands
Teepol
Knife blades
Potato Spindle
Viroid
Knives
Borax
Ethanol
Formalin
Sodium hypochlorite
flame
Sodium hypochlorite
Alcide LD
Incyte
Trisodium phosphate
Virus
Arabis
(AMV)
mosaic Virus
Tuber
Tobacco Mosaic virus
(TMV)
Tomato Mosaic Virus
(ToMV)
ToMV
Tools, Hands, Clothing
Hands
Tri-sodium
phosphate
washing detergent
Tools
Pruning Shears
Trisodium phosphate
Trisodium phosphate
Smith
1988
+
et
al.
10%/1 sec
95%/1 sec
3 % / l sec
0.2-1.0%/l sec
4-8 sec
1-5.25%/5 sec
10%/5sec
25%/ 5 sec
5%/5 min
Roistacher
al. 1969
et
3%
Broadbent
1963
3%/60 min
10%/15 sec
Sing
1989
et
al.
Brock 1952
Pategas et al.
1989
1.3.2 Effective control of fungi
Nurseries typically face situations where water, media or soil, which may be contaminated with pathogens
such as Phytophthora spp., is accidentally spilled onto paths, gravel beds or concrete floors and should be
cleaned and disinfected. There is little information in the literature on the efficacy of this kind of
disinfestation treatment. Gerritse et al. (1992) found that treatment of soils with copper at 0.5g Cu / kg of
regolith or 0.1-0.2 g Cu2+/ kg sandy soil was sufficient to control P. cinnamomi. They also found that soaking
P. cinnamomi infested soil with hypochlorite at 0.5g OC1 / g organic carbon for 24 h controlled the fungus,
but the rate of application is suitable only to treat spills of infested soil. An effective disinfestation dose
applied to soil therefore varies, depending on its organic carbon content, from approximately 0.5 to 3.5g
OC1 / kg of soil (Gerritse et al. 1992). Quinlan and Davison (pers comm. Colquhoun), however have
assessed the use of Agrigard®, a quaternary ammonium compound and substituted phenols, Microgen® and
Pine Fresh® on the survival of P. cinnamomi and P. citricola. They found that only Microgen® and
Agrigard® significantly reduced the survival of the fungi in colonised millet seed, but only at 4 times the
recommended rate, and only after 24 hr contact time, whereas Pine Fresh had little effect on P. cinnamomi
and P. citricola. However in soil, the fungi were recovered 24 hr after the recommended treatments with
Microgen® or Agrigard® but were not recovered after 7 days.
The results indicate that long contact times are required for adequate chemical disinfestation of soil and
colonised organic matter. The implication for nursery operators is that the concentrations of chemicals tested
would not satisfactorily disinfect soiled equipment surfaces or shoes rapidly enough for use in footbaths or
10
NY 612
Surface Disinfestation of Plant Pathogens for the Nursery Industry
for pruning or grafting tools, benches or pots where rapid surface disinfestation is required. Currently
available disinfectants however may be adequate for the disinfestation of surfaces where long contact times
are achieved, for example, gravel, sand or soil beds. Little work has been done on disinfestation of tar or
concrete surfaces which may chemically react with disinfectants and alter their efficacy, thus disinfestation
data obtained on other surfaces may not be applicable to paths.
Steam-air sterilisation of organic matter, such as seed and pine wood plugs, colonised by P. cinnamomi and
P. citricola has been achieved after 15min at 45°C and 55°C respectively while Armillaria luteobubalina was
controlled in colonised seed after 15min treatment at 47.5°C (Colquhoun pers. comm.). The work indicates
the possibility of hot water or steam-air disinfestation of contaminated nursery equipment and tools and pots.
Steam disinfestation of benches, floors and walls may be achieved, especially at high temperatures (eg
120°C) over short intervals but there are few data to support this, especially with plant pathogens.
Disinfestation of peat contaminated with Verticillium dahliae, Didymella bryoniae and Pythium sp. on the
surface of was achieved by soaking in 3% of the iodophore IobacP®/15 min, 1% gluteraldehyde/ 60 min or
10% sodium hypochlorite/ 60 min (Avikainen et al. 1993). None of the disinfectants controlled Phomopsis
sclerotioides in sand or peat, however, 5% formalin soak for lhr had a 96% 'disinfestation efficiency',
indicating that disease did develop in plants grown in treated material.
The work of (van Wambeke, 1995) on microwave radiation for the control of pathogens in substrates such as
potting media and on ultrasonic treatment of fungal spore suspensions indicates that these methods may have
potential for the non-chemical disinfestation of seedling trays, pots and tools.
Table 1.3 Information on the control of fungi in the nursery.
Fungus
Chemical
Rate
Reference
Seed - potato
Sodium hypochlorite
0.5%
Martin & Torres 1989
Benches, equipment
Sodium hypochlorite
Dimanin
Sodium hypochlorite
1.0%
0.5-1.0%
1:9 dilution
20%
Phytophthora
cinnamomi
Phytophthora
cinnamomi
Phytophthora
cinnamomi
Benches, equipment
Quaternary
ammonium
compound
Sodium hypochlorite
1-200 ppm
Smith 1976
Water
Sodium hypochlorite
2 ppm/1 min
Smith 1979
Soil
Sodium hypochlorite
Gerriste et al. 1992
Aspergillus spp.
Seed - wheat, soybeans,
rough rice, tomato, cucumber
0.5g/g organic
carbon
100 ppm
1-5%
Fusarium
sp.,
Curvularia
lunata,
Botrytis cinerea
Common
| Method of Transmission
Pythium spp.
Hydroponic system
Pythium sp
Peat
Plastic pots
with peat
Peat
Plastic pots
with peat
Peat
Sand
Verticillium dahliae
Phomopsis
sclerotioides
Copper (Cu2+)
Sodium hypochlorite
Cornell Cooperative
Extension 1995
Ethanol
then
sodium
hypochlorite
Sodium
hypochlorite
and
Calcium hypochlorite
Sodium hypochlorite
70-100% then
1-5%
2.5-5 ppm
Formalin
5%/15min
Sodium hypochlorite
Formalin
Formalin
10%/15min
5%/l hr
5%/l hr
Sodium hypochlorite
Sodium hypochlorite
10%/10 min
10%/15 min
Jeyes Fluid Wash
2
tsp
gallon
contaminated
10%/1 min
10%/10 min
Sauer
1986
&
Burroughs
Jenkins 1981
Avikainen et al. 1993
contaminated
Avikainen et al. 1993
Didymella bryoniae
Common
Cucumber debris
Plastic pots contaminated
with peat
Propagation Areas - benches,
walls, ceilings
Common
Seed
Common
Bench and tools
Dentolite
Dinamin-A
Copper sulphate crystals
Captan 75W (orthocide)
Thiram 75W
Phenol
11
per
Rumbal 1977
Ormrod 1975
Ormrod 1975
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Fungus
Method of Transmission
Pythium
spp.,
Phytophthora spp.
Common
Footbath
Pythium sp.
Sand Bed
Thielaviopsis
basicola
Sand Bed
Formalin
Copper napthenate
Hypochlorite
Formalin
Tar oil
Formalin (38%)
Dichlorophen (panacide 30%)
Formalin (38%)
Bench, ground
Tar oil (Clearsol 40%)
Dichlorophen (panacide 30%)
Glutaraldehyde + QAC
(Omnicide)
Sodium hypochlorite
Secateurs, knives
Benches, floors
Thielaviopsis
basicola
Chemical
Quaternary ammonium
Chlorine
Formalin
Formalin
NY 612
Reference
Rate
McCully & Thomas
1977
Goss 1978
4ml/litre
57g/litre
5.1g/litre
57g/litre
O'Neill 1995
O'Neill 1995
4ml/litre
5.1g/litre
"""67525%
""" Copes
&
Hendrix
1996
Thielaviopsis
basicola
and
Cylindrocladium
scopahum
Olpidium brassicae
Asbestos, glass, wood,
Synthetic material, clay,
sand, peat
Concrete, other surfaces
Sodium hypochlorite + Sparkle
Captan 50 WP (43.7% a.i.)
quaternary ammonium
compound: aldehyde + alcohol
quaternary ammonium
compound
Iodel
Fungi, nematodes
Rockwool
Nutrient solutions
Microwave radiation 2450 MHz
Ultrasonic treatment
Common
Woodwork, tools, pots,
pathways, footbath
Copper napthenate solution
Formalin (35%)
Sodium hypochlorite
0.525% + 5g
3.0g/litre
various / 4 hr
contact
20
min
600W
100W, 63 kHz
2%
1:50 water
12.5%
1%
Voss and Meier 1989
Tomlinson
et
al.
1981a
van Wambeke 1995
Baker 1957;
Hanger 1980
DPI Queensland suggested the use of 2,500 to 5,000 ppm available chlorine for the cleaning and surface
sterilisation of seedling trays, punnets or other containers to control black root rot (Chalara
elegans/Thielaviopsis basicola). It is recommended that polystyrene seedling trays are not re-used as infected
roots embedded in the tray cannot be effectively sterilised by a chlorine dip (DPI 1994).
A comprehensive study of disinfestation of typical glasshouse materials was undertaken by Voss and Meier
(1987) who colonised sections of irrigation mat, synthetic material, asbestos, glass, wood, clay, sand and peat
with either microsclerotia of Cylindrocladium scoparium or chlamydospores of T. basicola then subjected
them to a range of disinfectants for 4 hours. They found that a quaternary ammonium compound, M &
ENNO Ter Super® (except on sand), and a mixture of aldehyde and alcohol, Orbiplant Special® (except on
asbestos), effectively disinfected most materials from T. basicola chlamydospores while hydroxyquinoline
sulphate, phenol and a mixture of organic acid and hydrogen peroxide were not effective on most materials.
All disinfectants however, effectively disinfected the irrigation mats of T. basicola. Voss and Meier (1989)
found that the microsclerotia of C. scoparium. were more resistant to disinfestation, where only the
quaternary ammonium compound disinfected most materials but did not disinfect the synthetic material.
1.3.3 Effective control of bacteria
Disinfestation of bacteria from a variety of surfaces has been assessed in a number of studies (Table 1.4),
often with significant reductions in viable bacteria but, in many cases, a small proportion surviving.
Table 1.4 Information on the control of bacteria in the nursery.
Bacteria
Pseudomonas syringae pv
phaseolicola
Method of Transmission
Seed - bean plant
Erwinia amylovora
Pruning Shears
Erwinia amylovora
Apple surface
Chemical
Mancozeb
Captan
Falisan
Sodium hypochlorite
Quaternary ammonium
compounds
Sodium hypochlorite
12
Rate
5%
10%
500ppm/10min
Reference
Naumann & Karl
1988
Kleinhempel et al.
1987
Roberts & Reymond
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Bacteria
Method of Transmission
Common
Benches, equipment
Pseudomonas
solanacearum
Recirculating hydroponic
system
Erwinia carotovora
subsp. carotovora, E.
chrysanlhemi
Iris rhizomes
Erwinia carotovora
subsp. atroseptica and
Clavibacter
michiganensis. subsp.
sepedonicus
Clavibacter
michiganensis subsp.
sepedonicus
Wood, metal plastic
Jute
Cutting knives
Clavibacter
michiganensis subsp.
sepedonicus
Wood
Clavibacter
michiganensis subsp.
sepedonicus
Erwinia carotovora
subsp. atroseptica
Common
Wood, metal, burlap
Common
Wood, metal, burlap
Propagation Areas benches, walls, ceilings
Woodwork, tools, pots,
pathways, footbath
NY 612
Reference
1989
Chemical
Chlorine dioxide
Benzalkonium chloride
Sodium hypochlorite
Rate
200ppm/15 min
2000 ppm/10 min
1:9 dilution
Quaternary ammonium
compounds
Chlorine and Calcium
20%
2.5-5 ppm
Jenkins 1981
Chlorine
Sodium hypochlorite
100 ppm
20 ppm
Lacy et al. 1981
Quaternary ammonium
compounds 2.8
Iodine 1.8(IobacP)
Gluteraldehyde 10
2%/20min
Quaternary ammonium
chloride
Mercuric chloride
Hydroxymercurinitro-phenol
Quaternary ammonium
compounds
Sodium hypochlorite
Iodine
Phenol based chemicals
Hydrogen peroxide
Hot water
Formaldehyde
Mercuric chloride
Formaldehyde
Mercuric chloride
300 ppm
Cornell Cooperative
Extension 1995
Koponen et al.
1992
3%/20 min
3%/20 min
"T6 min 1:501:200/10 min
(various
(dilutions/10 min
}
Undiluted
82°C
5%/ 5 min
0.1%/5 min
2 and 5% 5 min
0.1%/5min
MacLachlan 1960
Secoretal 1988
Letal 1977
Jeyes Fluid Wash
2 tsp per gallon
Rumbal 1977
Dinamin-A, Dentolite
Copper sulphate crystals
Copper napthenate solution
2%
Baker 1957,
Hanger 1980
Formalin (35%)
Sodium hypochlorite
1:50 water
12.5%
The surface condition of cutting tools determines the relative efficiency of disinfectants and subsequent
spread of diseases. Kleinhempel et al. (1987) found that within the indentations and holes of the steel surface
of cutting tools, Erwinia amylovora escaped contact with disinfectants because the bacteria were protected by
air-cushions or by several layers of infective agent cells. Of the disinfectants tested, only BAC (quaternary
ammonium compound, 10% aqueous solution) and a 5% NaOCI solution reduced the number of infection
sites (Kleinhempel et al. 1987). Surface disinfestation of E. amylovora on Red Delicious apples with 500
ppm NaOCI for 10 minutes reduced recovery from 68 million to 38 bacteria/apple (Roberts and Reymond
1989). In the same experiments, chlorine dioxide at 200ppm/15 min and benzalkonium chloride at 2000 ppm/
10 min did not completely control E. amylovora.
Disinfestation of Clavibacter michiganensis subsp. sepedonicus and E. carotovora subsp. atroseptica
contaminated wood, metal and fibres has been studied extensively in the potato industry (Knorr 1947;
MacLachlan 1960; Letal 1977; Secor et al. 1988; Koponen et al. 1992). The efficacy of formaldehyde as a
surface disinfectant varied, but a 10 min contact with 5% formaldehyde solution on all materials was effective
against the two bacteria (Letal 1977). Disinfectants such as Hibitane, Dettol and quaternary ammonium
compounds were not effective for both bacteria (Letal 1977; Secor et al. 1988). Undiluted hydrogen peroxide
was effective against the two bacteria and has the advantage of leaving no chemical residues. Copper
sulphate (24g/L), iodine compounds and chlorine dioxide effectively controlled C. michiganensis subsp.
sepedonicus contaminated wood (Secor et al. 1988).
Soils may be heat sterilised to control fungi and bacteria; autoclaving soil for 120°C/40 min or microwave
treating the soil at 650Watts/6 min (Chen et al. 1995).
13
Surface Dis infestation of Plant Pathogens for the Nursery Industry
NY 612
1.3.4 Effective control of nematodes
The currently accepted methods of nematode control usually involve steam-air pasteurisation (60°C/30 min),
highly toxic chemicals such as carbamates (eg Aldicarb), or fumigants such as methyl bromide where soil or
potting mix requires disinfestation (Goss 1983). Other methods of nematode control can be made using less
toxic chemicals where water, media or surfaces require disinfestation. The root knot nematode, Meloidogyne
javanica, is a pathogen on many hydroponically grown crops, and is found in irrigation water and plant
substrates. The nematode was controlled in hydroponic solutions and in peat-vermiculite mixture after 24h
treatment with water containing 4 ppm HOC1 (Stanton and O'Donnell 1994). The treatment however, did not
affect root galling or egg mass production when applied as a post-plant. The nematicidal properties of a
wide range of phenolic compounds on three nematodes indicated that phenol and a range of chlorinated
phenols had similar toxicity to nematodes as Aldicarb, a conventional nematicide (Malik et al. 1989).
Undissociated acetic acid (pH < 5.5) was shown to be toxic to nematodes, where 20-200 ppm caused
paralysis to 2° stage juveniles of a wide range of species {Meloidogyne sp., Heterodera sp., Radopholus sp.,
Pratylenchus sp., Helicotylenchus sp. and Xiphema sp.) but not leaf and stem parasitic nematodes
(Ditylenchus sp., Aphelenchoides sp. and Bursaphelenchus spp. (Djian et al. 1991). The toxicity of acetic
acid was shown not to be a pH effect but the ability of the non-polar acid to penetrate the nematode cuticle.
The acetate anion, however, which carries a negative charge could not penetrate the cuticle and was
ineffective in paralysing the nematodes. Djian et al. (1991) showed that in general, non-polar molecules such
as short chain fatty acids (eg formic, acetic, butyric, propionic and valeric acids) are toxic to plant parasitic
nematodes and that these are naturally produced with the decomposition of organic matter. Composts used in
the Philippines have been shown to suppress plant parasitic nematodes (Castillo 1985).
Ammonia fertilisers such as calcium cyanamide, urea and ammonium sulphate have been shown to suppress
plant parasitic nematodes in soils, but were only effective at rates of application that are phytotoxic to plants.
D'Addibbo et al. (1996) showed that 0.5g N as calcium cyanamide/kg soil totally suppressed populations of
Meloidogyne incognita in sandy soils but was phytotoxic if applied after seedling transplant. Other ammonia
fertilisers suppressed nematodes but were not as effective as calcium cyanamide.
1.4
Hygiene practices in other industries
In other industries, hygiene is a major determinant in the quality of products. In the dairy industry, hygiene
in milking sheds and processing plants will determine the relative life and quality of the goods supplied to the
market. Contamination of foodstuffs causes sickness amongst consumers. Products may become
contaminated because of lax cleaning and sanitation practices. Similarly, in the medical industry
contamination in hospital situations could cause serious complications or premature death of patients.
Information on the sanitation and cleaning practices of the dairy, food, medical and other industries has been
investigated below. Chemicals from these industries may be useful in horticultural situations such as the
cleaning and sanitation of hands and equipment.
1.4.1 Dairy industry
The reduction of post-pasteurisation contamination by bacteria is one of the most important requirements of
the dairy industry. The cleaning and sanitising of processing equipment is essential in the production of high
quality milk (Bigalke 1979) and high grade dairy processed foods (Gelda 1974). The success of an effective
cleaning and sanitising program is dependent on the people involved. Bigalke (1979) believes that there are
four elements of an effective quality control program. These requirements are:
•
Plant personnel should be aware of and understand the importance of cleaning and sanitising
•
Employees should be properly trained
•
Only responsible people who are properly motivated are employed to clean and sanitise equipment
•
Communication is essential between control personnel, management, and sanitation personnel.
A survey of dairies in New Zealand revealed that of overall labour costs, cleaning had the largest outlay at
43% (Tomlinson et al. 19816). This shows the importance of cleaning and sanitation in the dairy industry to
supply goods that are of high quality and free from contamination. Some of these principles as identified by
Bigalke may be applied to the horticultural industry to improve quality and production.
14
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Cleaning chemicals commonly used in the dairy industry may be used separately or as a mixture. They are
made up of alkalis, acids and surface active or wetting agents. Alkalis include compounds such as sodium
and potassium hydroxides in combination with silicates, polyphosphates and soda ash. They are used to
dissolve proteins and to saponify fats. Acids such as phosphoric, muriatic (hydrochloric) and sulfamic acid
(S03HNH2) are used to remove water scale and milkstone. Surfactants or wetting agents are used to enhance
the efficiency of cleaning mixtures. Sanitising compounds commonly used include chlorine, iodine, and
formaldehyde. They are used either in combination with surface active agents or alone and all have efficient
bactericidal properties (Gelda 1974). Cleaners are used to remove soils and other large particles, while
sanitisers are used to inactivate microorganisms that may remain behind (Krysinski et al. 1992).
Unipon RD® is a combined, lightly foaming, alkaline detergent/disinfectant intended for use on dairy
installations and utensils. It is used at a concentration of 0.5-2% and at up to 50°C. Hoffer and Winterer
(1982) found that the bactericidal effects and cleaning and disinfecting efficiency of Unipon RD® were
satisfactory. The New Zealand recommendation for cleaning and sanitising requires the twice daily
application of a hot alkaline detergent and pre-milking iodophor rinse (Tomlinson et al. 1981 b).
UV radiation is used in the dairy industry for the sterilisation of air, water and equipment surfaces. UV
radiation at wavelengths between 220-300 nm have been reported to give good sterilising effect, and
specifically, bactericidal efficiency was found to be best at 250-260 nm (Morgan 1989). The disinfestation
efficacy of the chlorinated sanitiser dichloro-s-triainetrione and 0.5 ppm ozone in water/ 10 min was found to
be similar when compared on stainless steel surfaces (Greene et al. 1993). They found that the chlorinated
sanitiser and ozone reduced populations of Pseudomonas fluorescens and Alcaligenes faecalis by 1/10,000 to
1/100,000 of untreated surfaces. The results indicate that ozonated water may have application as a surface
disinfectant in nursery situations but would require longer contact times than for currently available sanitisers.
1.4.2
Food industry
The human rotavirus and Escherichia coli can be transmitted on the hands of workers to clean food stuffs.
Hand washing with alcohols (70%) alone or with Savlon® reduced the virus concentration by greater than
99%. Proviodine®, Dettol® and Hibisol® also reduced levels by 95 to 97%. Aqueous solutions of
chlorhexidine gluconate were significantly less effective than 70% alcohol solutions. A 1:200 dilution of
Savlon® in water was found to be much less effective in eliminating the virus (80.6%) than the bacterium
(98.9%). Tap water only and soap each produced the similar results with a reduction in virus concentrations
by 83.6 and 72.5%, and bacterial concentrations by 90 and 68.7% respectively (Ansari et al. 1989). The
results show that tap water and soap are not as efficient in reducing virus and bacteria transmission as
chemical disinfectants. This was confirmed by research conducted by Terbijhe (1976) in a poultry processing
plant. The bacterial count on processing surfaces was not reduced when washed with water, even though the
surfaces looked clean. Surfaces were sterilised when the water wash was followed by an application of
disinfectant (Terbijhe 1976).
Since packaging systems in the food industry are often required to be sterile for large quantities of material, a
fumigant is required as it gives a uniform application over the treated surface. Super heated steam (150°C)
and hot air mixtures are often used for glass or metal containers, while heat sensitive materials such as
plastics may be treated with ethylene oxide or hydrogen peroxide (H 2 0 2 ) in the vapour phase (Wang and
Toledo 1986). Ethylene oxide however is a slow acting disinfectant and requires extended contact times. A
99.999% reduction of viable Bacillus subtillus spores on polythene surfaces was achieved by either a 90 sec
dip in 35% H 2 0 2 at 40°C or 20 min exposure to 0.275 ppm H 2 0 2 at 20°C in the vapour phase. Wang and
Toledo (1986) showed that the resistance of spores to disinfestation by 35% H 2 0 2 solution decreased
logarithmically with increased temperature. Warm to hot solutions of H 2 0 2 were more effective than cold
solutions. Klapes and Vesley (1990) however found that B. subtillus spores on stainless steel surfaces of a
centrifuge were inactivated by vaporised H 2 0 2 after 8 min at 4°C but only after 32 min on surfaces at 27°C.
The elevated temperature and higher surface/volume ratios were said to contribute to a higher rate of H 2 0 2
decomposition, therefore decreasing the effectiveness of the disinfestation. Rij and Forney (1995) showed
99.9% of Botrytis cinerea spores on a contaminated glass surface failed to germinate after 8 min and 16 min
exposure to 0.27 ppm H 2 0 2 vapour at 20°C and 0.55ppm H 2 0 2 vapour at 30°C respectively. The results
indicate that H 2 0 2 may be a useful disinfectant in the nursery industry, either as a liquid or as a vapour. A
vapour phase H 2 0 2 disinfestation treatment however, may not be useful in the nursery unless equipment to be
disinfected is absolutely dry, as free water will rapidly remove H 2 0 2 vapours from the atmosphere and reduce
the efficacy of the treatment (Rij and Forney 1995). A silver stabilised H 2 0 2 solution, Sanosil-25®, has been
found to completely inhibit spore germination of B. cinerea and Alternaria alternata spores in water after 20
15
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
min exposure at 0.7% and 1% v/v respectively (Fallik et al. 1994). Similarly, eggplants and sweet peppers
dipped in 0.5% Sanosil-25® solution had reduced decay development in storage and increased shelf life.
Biofilms inhibit the ability of many chemicals to clean and sterilise. A biofilm is a group of microbes
embedded in an organic matrix, adhering to a surface and are often found in pipes and other surfaces where
water is commonly present. Microorganisms are distributed unevenly in a biofilm which consists largely of
water and a mixture of extracellular polymers (Carpentier and Cerf 1993). Listeria monocytogenes attaches
quickly to plastic and stainless steel surfaces. Once attached, the cell's biochemistry and physiology changes
and it becomes resistant to chemical sanitisers. If not attached to a surface, 200 ppm chlorine or QAC or 25
ppm iodophor induces a 99.999% reduction of organisms within 30 sec. The most effective biocides on
attached organisms were acidic quaternary ammonium, chlorine dioxide, and peracetic acid. Mixed halogens
(Divosan®) and acid anionics (K-San® ) were reported to be slightly less effective disinfectants. The
commonly used sanitisers in food processing facilities such as chlorine, iodophors, and neutral QAC were the
least effective chemicals against the biofilms (Krysinski et al. 1992).
Domenichini (1979) reported that the prevention and control of insect and other infestations must rely not
only on the use of chemicals, but also on ecological measures to create conditions adverse to the spread and
growth of microfauna and microflora. Hygiene is the essential requirement for clean and contamination-free
foodstuffs and factories. The comments could be equally applied to the nursery industry.
1.4.3 Medical industry
There are four main areas for disinfestation in hospital situations. Kelsey and Maurer (1972) determined that
chemical disinfectants may be used in (a) the treatment of skin and mucous membranes, (b) the disinfestation
of instruments when physical methods cannot be used, c) making potentially infected items such as bedpans,
fabrics or crockery safe for subsequent handling, and (d) the decontamination of surfaces. Table 1.5 lists the
common chemical disinfectants used in hospitals.
Table 1.5. Hospital Disinfectants (Kelsey and Maurer 1972)
Disinfectant
Phenolics
Type
Black Fluids
White Fluids
Clear Soluble Fluids
Chloroxylenols
Trade Names
Jeyes fluid
Izal
Clearsol, Hycolin, Printol, Stericol,
Sudol
Dettol
Hexachlorophane
Zalpon, Steridermis
Chlorine
Hypochlorites
Iodine
Iodophors
Formaldehyde gas
Formalin solution
Glutaraldehyde
Chloros, Domestos + hypobromite,
Diversol BX
Benzalkonium chloride
Roccal, Cetrimide, Cetavlon
Chlorhexidine
Hibitane
Alcohols
Halogens
Aldehydes
Quaternary
ammonium
compounds
Diguanides
Chlorhexidine
Cetrimide
Cidex
+
Inactivated by organic matter.
Effective
against Gram-positive bacteria.
Effective against Gram-positive bacteria.
Wide range of antibacterial activity. Poor
penetration of organic matter.
Wide range of antibacterial
activity.
Inactivated by organic matter.
Wide range of antibacterial
activity.
Inactivated by organic matter.
Difficult and unreliable.
Wide range of antibacterial activity.
Wide range of antibacterial activity. Poor
penetration of organic matter.
Narrow range of antibacterial activity.
Inactivated by organic matter.
Limited range of antibacterial activity.
Inactivated by organic matter and cork.
Limited range of antibacterial activity.
Inactivated by organic matter, cork, plastic,
and cellulose.
Limited range of antibacterial activity.
Inactivated by organic matter, cork, and
cellulose.
Little disinfectant activity.
Savlon
Picloxydine
+
benzalkonium chloride
Pine Fluids
Comments
Wide range of antibacterial activity. Not
inactivated by organic matter. Absorbed by
rubber.
Jeypine, Zal
16
NY 612
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Hydrogen peroxide showed good antimicrobial efficacy and caused a distinct reduction and influence of
biofilms in natural water conducting systems in hospitals. Exner et al. (1987) found that the best biofilm
removal and control result was achieved by mechanical cleaning.
Stainless steel discs contaminated with faeces and Hepatitis A virus was cleaned with 2% glutaraldehyde, a
quaternary ammonium formulation containing 23% HC1 (toilet bowl cleaner), and sodium hypochlorite
(greater than 5000 ppm of free chlorine). The virus concentration was reduced by greater than 99.9% with
these treatments. Phenolics, iodine-based products, alcohols, and solutions of acetic, peracetic, citric and
phosphoric acids were unable to give similar results (Mbithi et al. 1990). Stainless steel cylinders, not
contaminated with faeces, and cleaned with organo-iodine complex + phosphoric acid-, effectively
inactivated Herpes simplex virus, Poliovirus, Vaccinia virus and Adenovirus (Gaustead et al. 1974).
Quaternary ammonium compounds and phenolic based disinfectants however, were not as effective iodine
based chemicals.
Hospital blenders with metal, plastic and glass goblets contaminated with Klebsiella aerogenes and can be
cleaned using a cold water rinse, detergent wash, detergent wash and disinfectant soak, detergent wash and
boiling water rinse, or autoclaving. Autoclaving was the only procedure that sterilised the blenders but this
could only be used with metal goblets. The most effective cleaning and disinfecting method for all the
blender types was a detergent wash with or without chemical disinfestation followed by a boiling water rinse
(Anderton and Aidoo 1991).
A range of hospital disinfectants were assessed in vitro by Vanachter et al. (1991) for the control of a range
of tomato pathogens and compared with formaldehyde. They found that Amocid® (180 g/1 sodium-orthophenyl-phenolate) was better than formaldehyde for the inhibition of growth and toxicity to Fusarium
oxysporum f.sp. radicis lycopersici, Didymella lycopersici, Phytophthora nicotianae var parasitica, a
Pythium sp. and Clavibacter michiganense. Vanachter et al (1991) found that other disinfectants such as
Dettol®, chlorhexidine, and chloramine T had good bactericidal properties but were less effective against
fungi.
1.4.4
Other industries
Information on the use of chemical cleaners in other industries is summarised in Table 1.6.
Table 1.6. Information on chemicals used for hygiene purposes
Chemical
1% Sodium hypochlorite
Reference
Morton et al.
1987
Brill 1987
Target Pathogen
Natural flora on ceramic tile
surfaces and grout joints
Staphylococcus
aureus,
Streptococcus
faecium,
Pseudomonas
aeroginosa,
Proteus mirabilis and Candida
albicans, mycobacteria
Escherichia coli, S. aureus,
mycobacteria and anthracoid
bacteria
Comments
Controlled wide range of flora.
Effective on surfaces
Son et
1987
Glutaraldehyde,
chloramine-B
and
formaldehyde foams
2-3cm thick (200-300 ml of liquid
disinfectant per m2) for 2-3 hours
Hydrogen
peroxide,
peracetic
acid,
formaldehyde, glutaraldehyde, propiolactone,
Lysoformin, Lysiformin 2000 and Tegodor
E. coli, S. aureus
Active on surfaces of buildings
and equipment.
Yarnykh
1986
Good disinfectant
steel
Nicklas
&
Bohm 1981
Dezokson-I (colourless or yellowish green
solution of hydrogen peroxide, acetic acid
and up to 5-7% peracetic acid with a
stabilising
additive).
0.001-0.05%
bactericidal in 10 minutes. 0.1-1% sporicidal.
"Hypochlor" (bubbling chlorine gas into 1000
litres of 7% sodium hydroxide solution)
3% active chlorine applied at 0.5 1/m2
E. coli, S. aureus, B.
rhusiopathiae and Bacillus
cereus
Up to 0.5% effective disinfectant
on unpainted and painted wood,
concrete, galvanised iron, rubber
and other surfaces
Polyakov
al. 1980
E. coli
Killed pathogen on building
surfaces after one hours exposure
Dudnitskii et
al. 1975
Lysovet PA (mix of phenols, aldehydes and
alcohols)
Neutral calcium hypochlorite (cone. 5-15%,
1.5-4.5% active chlorine)
0.3 or 0.5 1/m2 for 3 hours
S. aureus, S. faecium,
aeroginosa, P. mirabilis
17
P.
Satisfactorily
used
pathogen suspensions
surfaces.
against
and on
on stainless
al.
et
Surface Disinfestation of Plant Pathogens for the Nursery Industry
1.5
NY 612
Chemicals available in Australia
The number of chemicals registered in Australia specifically for general use on ornamental plants is listed in
Table 1.7. Many disinfectants for general use on surfaces however do not necessarily need to be registered
for use in the nursery industry if they are not to be used to treat the disease in the crop. Common
disinfectants, therefore, are not listed in the registration list.
Table 1.7. Chemicals registered for general use on ornamentals in Australia (Chemical Registration
Information System 1996)
Chemical
2, 2-DPA Sodium Salt
Aromatic Hydrocarbons plus Sethoxydim
Bitertanol plus Hydroxyquinoline
Bupirimate plus Hydrocarbon Solvent
Chlorothalonil
Chlorthal Dimethyl
Copper
Copper as Copper (II) Hydroxide
Copper as Copper Oxychloride
Copper Oxychloride
Cupric Hydroxide
Cyproconazole plus lodocarb
Dicamba Dimethylamine Salt
Dichlorophen
Pichloran
Etridiazole
Fosetyl
Iprodione
Mancozeb
Mancozcb plus Metalaxyl
Oxycarboxin
Phosphonic Acid
Phosphorous Acid as Mono-di Potassium Phosphite
Phosphorus
Procymidone
Sulfur (S) as Wettable Sulfur
Sulfur as Elemental Sulfur
Sulfur-Element-Crystalline
Sulfur-Element-Crystalline (cont)
Thiram
Ziram
Full Product Name
Graypon Grass Killer
Sertin 186 EC Selective Post-Emergence Herbicide
Bacseal Pruning Paint Fungicide
Nimrod Systemic Fungicide
Agchem Garden Fungicide Spray, Isk Bravo 720 Fungicide, Agchem
Bravo 500 Fungicide, Agchem Bravo 720 Fungicide, Bayer
Chlorothalonil 500 SC Fungicide, Isk Bravo 500 Fungicide, Isk Daconil
Flowable Foliage and Soil Fungicide, Nufarm Rover 500 Flowable
Fungicide, SDS Biotech KK Crotop 500 Fungicide
Isk Dacthal W750 Pre-emergence Herbicide, Agchem Dacthal W 750
Pre-emergence Herbicide, CRG Dacthal Weed Preventer Pre-emergence
Herbicide Dacthal W750 Pre-emergence Herbicide
Agchem Cuprox Fungicide Bactericide, Farmoz Coppurite Fungicide
Spray, Nufarm Copper Oxychloride Fungicide Bactericide
Kocide DF Fungicide
CCC Copper Oxychloride 50% DF Agricultural Fungicide, CCC Copper
Oxychloride 50% WP Agricultural Fungicide, Country Copperoxy 500
WP Fungicide, Lancop 500 WP Fungicide
Farm-Oz Copper Oxy 500 Fungicide
Kocide Fungicide. Multicrop Kocide Fungicide
Garrison Pruning Wound Dressing
Nufarm Dicamba 200 Herbicide
Kendon Kendocidc 480 Algicidc and Bactericide
Farmoz Diclosan 750 WP Fungicide
Uniroyal Chemical Terrazole WP 350 Wettable Powder Soil Fungicide
Aliette WDG Systemic Fungicide, Aliette Systemic Fungicide, Aliette
WG Systemic Fungicide,
Rovral Aquaflo Fungicide, Rovral WG Fungicide, Rovral Fungicide,
Rovral Liquid Fungicide
Chipco Fore Flo Fungicide. Nufarm Penncozeb Fungicide
Ridomil MZ 720 WP Systemic and Protective Fungicide
ICI Crop Care Plantvax 750 W Systemic Fungicide
Agri-Fos Supa 400 Systemic Fungicide, Agri-Fos Systemic Fungicide,
Davison Fossic 200 Systemic Fungicide, Farmoz Phos Acid 200
Systemic Fungicide, Fol-R-Fos 200
CM Phosacid 200 Systemic Fungicide. Grow Green Systemic Fungicide
Agchem Phozacid 400 Fungicide, Country Phospot 400 Systemic
Fungicide
ICI Crop Care Sumisclex 500 Wettable Powder Fungicide
Microthiol Special Wettable Sulphur Fungicide, Miticide, and
Insecticide
Farmoz Microsul DF Wettable Sulphur Fungicide/Miticide Spray, CRG
Microfine Wettable Sulphur
Barmac Wettable Sulphur Fungicide and Mitticide, BASF Kumulus DF
Wettable Sulphur Fungicide Spray, Riverland Horticultural Traders
Vinsul Fungicide Miticide, Schering Top Wettable Sulphur Fungicide
and Miticide
Barmac Thiram Fungicide. Farm-oz Thiram 800 WDG Fungicide
Farmoz Ziram 900 Wettable Powder Fungicide
18
Surface Disinfestation of Plant Pathogens for the Nursery Industry
1.6
Current best control methods
1.6.1
Equipment
NY 612
A number of disinfectants for the sterilisation of cutting tools and plants were considered by McClelland and
Smith (1993) with the aim of identifying alternatives to chlorine containing products. Hypochlorite solutions
were considered environmentally unfriendly as the break-down product, hypochlorite (OC1 ) combines with
organic compounds to form stable chlorinated organic compounds which may be taken up by plant roots,
absorbed by aquatic organisms and enter the food chain. McClelland and Smith (1993) recommended the use
of benzalkonium chlorides and hydrogen peroxide which break down into inert or harmless by products.
Hydrogen peroxide was found to be approximately double the cost of hypochlorite disinfectants as 30%
solutions were required for adequate disinfestation, but the by products, oxygen and water are
environmentally friendly. Hydrogen peroxide however is slightly corrosive on aluminium, but less so than
sodium hypochlorite (Wilde and McLaughlin 1981). Ethyl alcohol or formalin should not be used to
disinfect tools as they do not prevent transmission of virus (Brock 1952)
Nursery irrigation pipes may build up biofilms of bacteria which may harbour plant pathogens. Bacteria in
biofilms are generally more resistant to disinfectants (Potera 1996), but ozone treatment of water at 0.1 ppm
was found to be effective in the removal of Pseudomonas fluorescens biofilms on surfaces and shows
potential as a treatment to prevent biofouling (Bott 1991).
1.6.2 Paths and benches
The U.C. System recommends formalin for disinfestation of floors, structures and containers (Baker 1957).
Avikainen et at. (1993) found that formalin and sodium hypochlorite were the most effective disinfectants
against Verticillium dahliae in sand while quaternary ammonium compounds and potassium peroxysulphate
were ineffective. They also found that only formalin or peroxysulphate were the most effective for the
control of Verticillium dahliae peat, although 15-20% of cucumber seedlings planted in treated peat
developed V. dahliae infections. Iodine, sodium hypochlorite and quaternary ammonium compounds did not
control V. dahliae in peat after 60 minutes contact time. The results indicate that the presence of organic
materials on paths and benches interferes with the efficacy of sodium hypochlorite. In peat, all the
disinfectants were effective against Didymella bryoniae and Pythium sp. however, only formalin was
effective against Phomopsis sclertioides, although 15% of the inoculum survived treatment (Avikainen et al.
1993).
1.6.3
Pots
Formalin has long been recommended for the disinfestation of containers (Baker 1957; McCain 1977) but is
no longer available as it is carcinogenic. Avikainen et al. (1993) found that formalin (5%), iodine (as 3%
Iobac P®), sodium hypochlorite (10%), and a range of quaternary ammonium compounds (1-2%) effectively
controlled V. dahliae , Didymella bryoniae and Pythium sp. on pot surfaces after 15 minutes contact time.
Both Clavibacter michiganensis subsp. sepedonicus and Erwinia carotovora subsp. atroseptica have been
effectively killed on dirty pots after 20 minutes contact with Iobac P (3%), but sodium hypochlorite (10%),
Verkon S® (1%) and the quaternary ammonium chlorides Deskem-1® (0.2%), Menno-Ter-Forte® (1%) only
controlled C. michiganensis subsp. sepedonicus.
1.6.4
Plants
McClelland and Smith (1993) recommend that hypochlorite solutions should not be used to disinfect freshly
cut plant surfaces as they cannot be completely rinsed off and interfere with plant metabolism (Abdul-Baki
1974).
A number of chemical treatments for freshly cut Buxus microphylla and Peperomia caperata were examined
for their effect on the proportion of cuttings successfully rooted and on root development (Morgan and
Colbaugh 1983). Chlorine, Truban®, Lesan®, Subdue, Benlate®, Banrot®, Captan®, Manzate® and
Terrachlor® did not affect rooting of B. microphylla when drenched. However, when cuttings were soaked in
one of the chemicals, most cuttings produced few and shorter roots.
A solution of hypochlorite and sucrose was successfully used by Bunker (1990) to disinfect rose cuttings
which also improved his strike rate, however, strike rates were not reported and it is not clear if the
improvement was due to sucrose or chlorine alone or the combination of the two chemicals.
19
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Mercury, Terramycin and Agrimycin were effective in disease control on potato seed pieces infected with
Clavibacter michiganensis subsp. sepedonicum while quaternary ammonium chlorides did not provide
control (MacLachlan 1960). None of these effective products however are available in Australia for nursery
use. A study on the efficacy of disinfestation of harvested apples by Roberts and Reymond (1989) indicated
that while 500 ppm NaOCl / 15 min reduced the number of Erwinia amylovora from 6.8 x 107 to 38 colony
forming units per fruit, a small number of bacteria survived. The result indicates a useful degree of surface
disinfestation for most purposes, except where strict quarantine is required to exclude pathogens.
Use of hydrogen peroxide as a disinfectant of leaves, fruit and vegetable produce for the control of B. cinerea
and A. alternata has proven effective (Kinkel and Andrew 1988, Fallik et al 1995, Rij and Forney 1994) and
may find application as a plant disinfectant in the nursery industry. Kinkel and Andrew (1988) showed that a
75-90 sec immersion of living Malus pumila leaves in 15% H 2 0 2 did not cause any phytotoxic effects yet
reduced the population of bacteria, A. alternata, Microsphaeriopsis spp. and Cladosporium spp. by 99% of
the original phylloplane. The treatment however was not sufficiently effective for use in nurseries where
greater than 99% efficacy is required.
A comparison of disinfectants on Phytophthora cinnamomi colonised Banksia sp. leaves indicated that
quaternary ammonium compounds were more effective than either phenol based compounds, such as
Biogram, or sodium hypochlorite when used as a 2 minute dip for plant disinfestation (Noske and Shearer
(1989). There were no significant differences between four quaternary ammonium compounds tested,
Superquat®, Applied 3-300®, Liquitain® and Chemene®, however, none of the treatments completely
controlled growth of P. cinnamomi.
1.7
Summary
There is a large body of data on general hygiene practices available but much of it lacks specific data on the
spectrum of activity or the efficacy of disinfectants.
1.8
•
Many of the disinfectants studied are no longer used for various reasons.
•
Ethanol, ethanol + flame, phisohex®, formalin, borax or benzalkonium chlorides cannot be used as
general tool disinfectants as they do not adequately inactivate viruses.
•
Iodine, sodium hypochlorite and quaternary ammonium compounds effectively control fungal
pathogens on pot surfaces after 15 min, but do not control the same pathogens in peat, even after 60
min contact.
•
Most widely used disinfectants used for tools or equipment need long contact times to be effective.
•
Rapid disinfestation required for footbaths and for cutting tools needs further development.
•
Formalin is carcinogenic and can no longer be recommended.
•
Little information exists on disinfectant concentrations and contact times for adequate disinfestation
of various surfaces. Where studied, a contact time of 4 h was required for disinfestation of resistant
resting structures of pathogenic fungi.
•
Quaternary ammonium chloride or aldehyde/acid alcohol disinfectants were the most effective
disinfectant chemical groups for the control of fungi contaminating a wide range of glasshouse
surfaces.
•
Information on the spectrum of activity of disinfectants needs to be collected to improve current
hygiene recommendations.
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26
Surface Disinfestation of Plant Pathogens for the Nursery Industry
CHAPTER 2
2.1
NY 612
ALGAE
Introduction
Algae are a major problem in nurseries. Growth of algae on pots and plants for sale is unsightly, reduces
water penetration, on floors it is slippery and dangerous to staff, on glasshouses reduces light levels and, on
benches and media, they act as a refuge and food for for pests such as shore flies and fungus gnats (Goodwin
and Steiner 1996).
Copper compounds are effective for control of algae on paths and benches, however, research has shown that
copper is mobile in drainage water and concentrations above EPA levels can leave some nurseries to end up
in water bodies if water is not recycled or in dams on site (James and Beardsell 1995). High copper ion levels
in water can cause imbalances in its microflora and fauna, such as the death of algae and fish (Kong et al.
1995).
The purpose of this chapter is to review what is known about algae and how to control them in nurseries and
on surfaces often found in nurseries, such as walls and paths.
2.1.1
Definition
Algae are either simple plants (green, brown and red algae) or cyanophytes (blue-green algae) which are
more like bacteria in cellular structure. They do not have true leaves, roots, or stems. Algae are often
mistaken for moss, liverwort and fungi. Many species of algae grow in an association with a fungus species
producing a lichen (Prescott 1969). A number of species belonging to the Trentaportiaciae are parasitic on
plants such as magnolia, oleander and lychee, oil palm, mango and tea (Prescott 1969, Sharma 1991,
Barthakur et al. 1992, Dalvi and Sardeshpande 1993).
2.1.2
Species
There are many species of algae with a wide range of requirements for growth, some prefer saline conditions,
others are adapted to fresh water. Similarly, algal species will have a wide range of tolerances and
susceptibilities to algicides. Due to the vast number of species which occur in nursery environments
(Appendix 1), experimenters should have an understanding of the distribution of species present on sites
where algicides are being examined.
A survey of British nurseries found the following common algae species: Green-algae, Klebsormidium
subtillisimum, Chlorococcum humicola and Chlamydomonas species, Phormidium laminosum and Dinema
griseolum (Ross and Puritch 1980). A general review of algae growing on buildings was prepared by John (
1988, Appendix 1). The review was largely concerned with those algae that inhabit any object above the soil
or water surface. These algae can be found in nurseries on concrete paths, greenhouse structures and on
benches.
2.1.2 The algal problem
The control of algae in greenhouses and plant nurseries is complicated because:
1.
There are many species of algae, not one chemical will control all algae in all situations without
affecting the growth of nursery stock.
2.
A problem exists in selecting chemical controls for algae that do not harm or damage the materials
that the greenhouse is constructed of, ie. aluminium, concrete, wood and plastics.
3.
The chemical control needs to be environmentally and user friendly.
27
Surface Disinfestation of Plant Pathogens for the Nursery Industry
2.2
Climate and Environmental Conditions.
2.2.1
Ideal growth preferences
NY 612
The optimum conditions for the growth of most algae are much the same as for plant growth, that is, high
light, sufficient water and nutrients, especially nitrogen. Due to these similar climatic and environmental
conditions, a change in any one of them specifically to control algae will also have an adverse affect on the
crop being grown. Algae are often found where the humidity or moisture level is high. Changing any
environmental condition may control one algal species but may be favourable for another species. Algae,
like plants, require nutrients and have a preference for high levels of calcium, magnesium, nitrogen and pH
(Tubea 1979).
2.2.2
How are they spread ?
Algal cells can been sampled in air near algal colonies. Some algae found in dam water can colonise
subirrigation systems, although not all species will colonise nurseries (Bodman pers. comm.). Algae may
also be spread when algal cells are blown into the atmosphere, possibly attached to dust particles. Filtration
of intake air for cooling and heating greenhouses may minimise algal spread (Ross and Puritch 1980).
2.2.3
Life-cycle
Reproduction of algae can occur in three general ways:
1.
Vegetative reproduction - is common to all algae and involves multiplication by cell division or by
fragmentation.
2.
Asexual - zoospores are produced in great numbers and released to form colonies of algae.
3.
Sexual - male and female zygospores unite in water to form another alga.
These effective reproductive mechanisms enable algae to proliferate in any environmental circumstance, as
they can adopt one reproductive method over another (Prescott 1969).
2.3
Control Methods
2.3.1
Cultural and Mechanical
Mechanical removal of algae from floors and benches is very time consuming and costly. Brooms, scrapers
and high pressure hoses are used to clean benches and floors in many nurseries in Australia. This method
very often solves the immediate problem, but does not give long term control of algae. A chlorine solution is
frequently used in this process. With many jobs becoming automated in nurseries, a stacker and cleaner for
movable tables in greenhouses has been developed. The tables are inverted and dry swept with a bristle brush
over a hopper that has a vacuum attached. The stacker-unstacker has the capacity to stack or unstack about
1000 tables per day, using only one worker. A light chemical spray is then applied to cleaned tables and
controls algal growth (Young and Stricklin 1982).
Before plants are sold, pots with algae are wiped clean with a cloth or changed and any algae in the top of the
pots are removed by hand. This process is also time consuming and requires extra handling of pots. Due to
the ability of algae to spread in the air, very often the physical processes adopted for control are in fact
spreading algae. Chemical control may be essential to minimise spread.
2.3.2
Chemical
There have been many chemicals tested on algae around the world, directly to control algae or as a side effect
from an indirect application to control a weed, pest or disease. These tests have been done on a range of
species, many of which occur in water bodies such as lakes, ponds, streams or oceans. Some of these
chemicals work very well against some species of algae but poorly against others.
28
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
AC 322 (unspecified active ingredient)
Japanese gardens are designed gracefully and with much patience. Water, plants and rocks play a major role
in Japanese gardens. In such conditions algae may grow and ruin the "feel" of the garden. Formaldehyde
and AC322 have been used to control algae on rocks (Yamamoto and Kurumazuka 1986).
Agribrom®(bromochlorodimethylhydantoin/1-bromo-3-chloro-5,5-dimethyl-2,4-imidazolidinedione/BCDMH)
This chemical has been tested on subirrigation mats at a concentration of 4-5ppm. Crops of potted
chrysanthemums and Exacum affine were grown on the matting. No phytotoxic effects were seen in the
foliage, although roots did not emerge beyond the pots. The treated matting stayed white and free of algae
for 6 months. Pot plants were also sprayed with BCDMH at concentrations up to lOOOppm. Some flower
spotting was observed at lOOOppm and occasionally at lOOppm on zonal pelargoniums, gerberas, impatiens,
begonias and saintpaulias. Evaporative cooling pads were pulsed in a solution of BCDMH at lOOppm for 24
hours. The pads were cleaned of algae; plants growing in the house (poinsettia and pelargonium) showed no
phytotoxic effects (Tayama et al. 1986).
BCDMH is registered in USA (as Agribrom®) as a water additive for algal control in greenhouses, and tested
on cyclamen plants at 20-25ppm with no phytotoxicities when used as a fungicide (Powell and Smith 1989).
Algae were effectively controlled on pathways with weekly applications of 800ppm Agribrom® at 0.3 litres
solution/m2 over 4 weeks. Control continued for 2 weeks after the last application. A granular formulation of
Agribrom® was also used directly on pathways, but washed off and hence was not an effective control
method (Hickman and Viss 1989). The same product is marketed in Australia as Nylate® for post-harvest
disinfestation and the control of 'slime' and algae in irrigation lines. BCDMH is also available under a
variety of trade names as a pool disinfectant.
Algizit® (unspecified active ingredient)
Algizit® at 5 mg/L reduced the growth of Philodendron erubescens cv. Red Emerald and Dizygotheca
elegantissima (Hornis and Rober 1981).
BAS 278 15D (unspecified active ingredient)
BAS 278 15D was tested by Schwemmer (1981) against algae in pot plants growing in hydroculture. The
chemical was the least phytotoxic of five chemicals, including Alginex®, and was a moderately good algicide.
Brestan® (triphenyltinacetate)
Under laboratory conditions, Brestan® at 0.5ppm. killed the blue-green algae Oscillatoria sp. and
Cylindrospermum sp. (Ferrante and Viterbo, 1974). The efficacy of this chemical in the field and its
phytotoxicity to plants is unknown.
Copper compound (CA 9213 )
The Bayer copper compound CA 9213 at the rate of 8-10g/m2 prevented algae growth for two months on
watered sand beds, but was not effective against algae already present. There were no observed phytotoxic
effects on saintpaulias, Elatior begonias or poinsettias (Fischer 1973). The copper compound needs to be
determined and its mobility would also need to be assessed.
Copper sulphate
Copper sulphate was tested at the rates of 0.5-5.0mg/l by Hornis and Rober (1981), however no mention was
made in the German abstract of its effectiveness. Copper sulphate severely pits most aluminium alloys,
including those used on benches (Wilde and McLaughlin 1981).
Cyanophages/phycoviruses
These viruses could show promise as biological agents for the control of two genera of blue-green algae,
Microcystis and Nostoc in fresh water (Kaniuka 1974).
29
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Delegol® (unspecified active ingredient)
Container disinfestation was achieved by dipping in 2% Delegol® (Hemer 1980) and performed better than
Tenoran®, Alginex®, Anti-alga® and Dimanin® as a dip but Alginex®was better overall.
2,3-dichloro-1, 4-naphthoguinone (Dichlone®)
Dichlone® at 0.4 to 1 mg active ingredient /cm2 gave good algal control in styroblock containers and was not
phytotoxic to Pinus echinata (Pawuk 1983).
Dicopper dihydroxide carbonate (55.8% elemental copper), malachite.
This chemical at the rate of 17-28.5kg/Ha is effective in controlling algae in lakes, ponds, canals and
waterways (Geiger et al. 1973).
Dodine (Cyprex 65WP®)
Powell and Shumard (1984) tested Cyprex 65®, a foliar fungicide, for the control of algae. The rate of
6.1g/m gave adequate control of Chlorella spp., but they suggested further research was required to
determine the most effective mode of use.
Chase and Osborne (1987) tested Cyprex 65® on a range of greenhouse surfaces. Cyprex 65® at a rate of
0.9g/500ml gave good control of algae on capillary mats for over 10 weeks. Rates of 15 and 30.1g/500ml
gave good control on benches, and low rates of 0.2 and 0.5g/500ml gave good algal control on concrete.
Rates of 0.1-0.5g/500ml were ineffective for algal control on wood surfaces.
Hydrogen peroxide
Rates of 50ppm were required to control algae in a hydroponic system, however phytotoxicity occurred at
levels of 9ppm on Lepidium sativum and 12ppm on radish (Coosemans and Vanachter 1995). Hydrogen
peroxide applied to water only had minimal effectiveness against algae and had slight corrosion potential on
aluminium alloys (Wilde and McLaughlin 1981).
Maneb (manganese ethylene bis dithiocarbamate)
Treatment of watered sand beds with 0.2% maneb at 2 1/m destroyed existing algae, and at 0.1% it retarded
new algal growth for 3 months (Fischer 1973). Maneb at the rate of 0.8-1 mg active ingredient /cm" gave
good algal control and was not phytotoxic to Pinus echinata (Pawuk 1983).
2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine (Irgagol 1051®)
In vivo experiments indicated no algal growth after 3 months at an initial concentration of lOppm. At 1 and 5
ppm poor algal growth occurred after 2 months. A few days after application into a hydroponic system,
phytotoxicity occurred at levels as low as lppm, killing Lepidium sativum, radish and corn salad (Coosemans
and Vanachter 1995).
Oxidants (chlorine, ozone, chlorine dioxide)
All the above oxidants work well in destroying algae in waste water treatment (Sukenik et al. 1987). Sodium
hypochlorite however, had little algicidal ability at rates up to lOOppm and also caused severe corrosion to
aluminium alloys (Wilde and McLaughlin 1981).
PH 4062 (N-(4-cyclohexylphenol)-N',N'-diethylenediamine)
Both laboratory and greenhouse conditions showed that the growth of algae was significantly reduced by a 7
day exposure to 0.25ppm PH 4062 (Anderson and Dechoretz 1984).
Potassium permanganate
Potassium permanganate was less effective as an algicide than Diuron, but more effective than hydrogen
peroxide or sodium hypochlorite at 1, 10 and 100 ppm when algicidal properties were compared (Wilde and
McLaughlin 1981). Potassium permanganate, had no detrimental effect on aluminium alloys, unlike the other
algicides tested. The results indicate that potassium permanganate would be a suitable algicide where
aluminium surfaces are routinely exposed to algicide.
30
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Quinonamid (Alginex®)
Under laboratory conditions, quinonamid completely inhibited the growth of Oscillatoria sp. at 8 ppm and
gave 72% inhibition at 4 ppm. Growth of Cylindrospermum sp. was inhibited by 48% at 1 ppm a.i. and
completely stopped at 2 ppm (Ferrante and Viterbo, 1974).
Quinonamid has been trialed in a hydroponic system growing Lepidium sativum. At the rate of 2.5ppm algal
growth was fully inhibited, however the roots of Lepidium sativum were substantially inhibited (Coosemans
and Vanachter 1995). Alginex® at 9 mg/L in winter and 20mg/L in spring was most effective in control of
algae and did not harm the plants grown in containers (Hornis and Rober 1981).
Work by Netherlands Proeftuin Lent (1979) indicates that Alginex® at a concentration of 0.5% is sufficient
for preventative control, and 1.0% for curative control, and worked best at 10 C and 80% relative humidity.
The algicide was watered over azaleas and ivy cultivars in pots without phytotoxic effects.
Hemer (1980) tested five pesticides for the control of algae in greenhouses and outside crops, with Alginex®
being the most effective. The toxicology and biological activity of quinonamid were summarised by Hartz
and Schumacher (1975). Schietinger (1975) tested quinonamid at a rate of 2-5g/m2 for the control of algae in
potted plants. The chemical was effective and the test plants, anthurium, rhaphidophora, geranium and
bromelia were tolerant of the chemical although some leaf flecking was evident.
Thiram
Thiram at 5g/100m gave good control of algae on the leaves of 2 and 3 year old Kentia forsteriana in
containers (Himme et al. 1984).
Using Thiram at concentrations of 25 - 400ppm completely inhibited the growth of algae. The plant
Lepidium sativum showed no phytotoxicities at 25ppm, but other plants including lettuce, water cress, corn
salad and radish showed phytotoxicity at 25 ppm. No algicidal activity was reported at concentrations lower
than 14ppm (Coosemans and Vanachter 1995).
Many pesticides that are used agriculturally also have an indirect effect on algae. Table 2.2 is a review by
Butler (1977) and Pipe (1992) of chemicals which have been tested on algae as non-targeted organisms.
Many herbicides have been tested due to their possible destruction of the soil microflora, since herbicides are
targeted against chlorophyll producers. The use of herbicides for algal control may be effective on paths and
surrounding areas, but certainly would not be recommended on benches or plants. Even if the herbicide may
be effective for algal control at a lower rate, the potential confusion of the wrong rate or some percentage of
plant growth retardation is possible.
Fungicides and insecticides which show good algicidal properties and already are registered for use on crops
in Australia could be selected for further testing as the process for an extension of a chemical use is less
costly and less expensive than seeking registration for a new chemical. These chemicals are marked with an
asterix in Table 2.1.
Table 2.1. Reviews of interactions of pesticides on algae as non-target organisms.
Common name
2,4,5-T
2,4-D
2,4-D
Abate
Abate
Acarithion
Alachlor
Alachlor
Aldrin
Amer. cyanamid
Ametryn
Ametryne
Amitrole
Asulam
Atrazine
Atrazine
ref
b
b
b
a
a
a
b
b
b
a
b
a
b
a
b
b
Rate
900 ppm
up to 17.6 ppm
1,500-2000 ppm
0.01-lppm
10-1000 ppm
35ug/ml
150 ppm
21.6
1-8 ppm
1000 ppm
0.2 ppm
0.01-0.06 ppm
up to 6.4 ppm
6 ppm
0.06-5.36 ppm
5.7 ppm
Effectiveness
reduction of growth
no effect
complete inhibition
up to 80% reduction in oxygen production
growth stopped
minimum inhibitory concentration
3% survival
22% inhibition
inhibition
uptake and metabolism
effective concentration to control 50% of algal population
50% inhibition
no effect
50% inhibition
Effective concentration to control 50% of algal population
Effective concentration to control 50% of algal population
31
Herbicide
Herbicide
Herbicide
Fungicide
Fungicide
Fungicide
Herbicide
Herbicide
Insecticide
Fungicide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Common name
Atrazine
Baygon
Baytex
Baytex
Benomyl
Benthiocarb
BHC
Bromacil
Bromoxynil
Butachlor
Butachlor
Butachlor
Captafol
Captan
Carbaryl*
Carbendazim
Carbofuran
Carboxin
Carboxin*
CCC
Cerasan
Chloramben
Chloramben
Chlorfenac
Chloridazon
Chlorotoluron
Chlorotoluron
Chloroxuram
Chloroxuron
Chlorpropham
Chlorpropham
Chlorpyrifos-methyl
Copper oxychloride*
Cypermethrin
Dacthal
Dalapon
DDT
DDVP
Demeton
Diallate
Dicamba
Dimefox
Dinoseb
Dinoseb acetate
Diphenamid
Dipterex
Dipterex*
Diquat
Diuron
Dow Et-57
Dowacide A*
EBP
Endosulfan
Endothal
Endothal
Ethepon
Ethirimol
Fenithrothion*
Fenvalerate
Fluchloralin
Glyphosate
Guthion
HE-314
Imidan
Intrathion
Ioxynil
Isocil
Isoproturon
ref
b
a
a
a
b
a
b
a
b
b
b
b
b
b
b
b
b
b
b
a
a
b
a
b
b
b
b
a
b
b
b
a
b
b
a
b
b
a
a
b
b
a
b
b
a
a
a
b
b
a
a
b
b
b
a
b
b
a
b
b
b
a
a
a
a
b
b
b
Rate
2.2 ppm
0.01-1 ppm
0.01-1 ppm
lppm
15-24 ppm
5 ppm
4 ppm
5 ppm
0.7-1.4 ppm
2.5-20 ppm
6-8 ppm
20 ppm
1000 ppm
15-24 ppm
120 ppm
1000-1500 ppm
30 ppm
1.2 ppm
15-24 ppm
10-2-10-8M
0.1-100 ppm
up to 16.8 ppm
1.5-300 ppm
0.6 ppm
17.4 ppm
5 ppm
11.6 ppm
2 ppm
lppm
2.7-30.5 ppm
1.1-39.4 ppm
0.028kg/ha
0.25e
10-50 ppm
200 ppm
up to 11.2 ppm
4-100 ppm
3.5ug/ml
0.5%
10 ppm
up to 17.6 ppm
1000 ppm
4.3 ppm
17.4 ppm
10 ppm
lppm
10-1000 ppm
0.3 ppm
0.5 ppm
1000 ppm
10-1000 ppm
0.25e
50 ppm
0.3 ppm
225-5500 ppm
200-1000 ppm
50-100 ppm
50 ppm
10-50 ppm
300 ppm
68-590 ppm
lppm
50 ppm
7.5ug/ml
2.0ug/ml
7.1 ppm
100 ppm
100-500 ppm
Effectiveness
60-98% effect depending on species
13-53 reduction of oxygen production%
l-51%reduction in phytoplankton communities
7.2-60% reduction
algicidal
no effect
algistatic
66% reduction in lipid biosynthesis
some stimulation of growth
inhibition of growth
inhibition of growth
inhibition of growth
max. tol. limit
algicidal
complete inhibition
max. tol. limit
algistatic
variable stimulation
algicidal
blue -green algae
max.conc. permitting growth
no effect
50% inhibition
13% stimulation
suppression of growth
reduction in growth
total suppression
inhibited
reduction in growth
variable inhibition
Effective concentration to control 50% of algal population
phytoplankton increased
53% inhibition
no effect
no effect
no effect
Effective concentration to control 50% of algal population
minimum inhibitory concentration
altered morphology
inhibition
no effect
no metabolism
Effective concentration to control 50% of algal population
total suppression
stimulated growth
non-toxic
toxic
Effective concentration to control 50% of algal population
Effective concentration to control 50% of algal population
no metabolism
toxic
80% inhibition
inhibition
Control of 50% of Chlamydomonas moewus
50% reduction in oxygen production of marine algae
Effective concentration to control 50% of algal population
Effective concentration to control 50% of algal population
killed cells
no effect
variable survival
Effective concentration to control 50% of algal population
non-toxic
no effect
minimum inhibitory concentration
minimum inhibitory concentration
Effective concentration to control 50% of algal population
inhibition
survival
32
NY 612
Herbicide
Insecticide
Fungicide
Fungicide
Fungicide
Herbicide
Insecticide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Fungicide
Fungicide
Insecticide
Fungicide
Insecticide
Fungicide
Fungicide
Herbicide
Fungicide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Fungicide
Fungicide
Insecticide
Herbicide
Herbicide
Insecticide
Fungicide
Fungicide
Herbicide
Herbicide
Fungicide
Herbicide
Herbicide
Herbicide
Insecticide
Insecticide
Herbicide
Herbicide
Fungicide
Fungicide
Fungicide
Insecticide
Herbicide
Herbicide
Herbicide
Fungicide
Fungicide
Insecticide
Herbicide
Herbicide
Fungicide
Herbicide
Fungicide
Fungicide
Herbicide
Herbicide
Herbicide
Surface Dis infestation of Plant Pathogens for the Nursery Industry
Common name
Lenacil
Leptophos
Lindane
Linuron
M&B 8882
Malathion
Mancozeb
MCPA
Mecoprop
Metamitron
Metamitron
Methabenzthiazuron
Methathion
Methiocarb*
Methoxyethylmercuric chloride
Metobromuron
Metribuzin
Metribuzin
Molinate
Monocrotophos
Monuron
Nitrofen
Nitrofen
Paraquat
Parathion
Permethrin
PH-2846
Phenylmercuric acetate
Phenylmercuric acetate
Phorate
Picloram
Prometon
Propanil
Propazine
Quinalphos
Schradan
Schradan
Siduron
Swep
TEPP*
Terbacil
Terbutryn
Thimet
Thiobencarb
Thiram*
Trifluralin
ref
b
b
b
b
a
b
b
b
b
b
b
b
a
a
b
a
b
a
a
b
b
a
b
b
b
b
a
a
b
b
b
b
b
a
b
a
a
a
a
a
b
b
a
b
b
b
Rate
0.015-0.025 ppm
300 ppm
15 ppm
5 ppm
25 ppm
500 ppm
0.25e
10 ppm
100-1000 ppm
350 ppm
140 ppm
11.6 ppm
0.55ug/ml
50-1000 ppm
2 ppm
1-10 ppm
70 ppm
0.05-1 ppm
0.25-25 ppm
100 ppm
67.6 ppm
50 ppm
100 ppm
0.5 ppm
10 ppm
0.5 ppm
50 ppm
50-500ppm
0.7 ppm
1000 ppm
19.2 ppm
10.4 ppm
0.09-2.65 ppm
1-2000 ppm
10 ppm X 2
0.001-0.14%
1000 ppm
100 ppm
5 ppm
100-1000 ppm
100 ppm
11.6 ppm
1000 ppm
6-8 ppm
0.12 ppm
2 ppm
Effectiveness
Effective concentration to control 50% of algal population
maximum tolerance level
maximum tolerance limit
reduction
50%
some survival
77% inhibition
inhibition
Effective concentration to control 50% of algal population
complete inhibition
no effect
total suppression
minimum inhibitory concentration
killed cells
max. tol. limit
Chlamydomonas more susceptible than Chlorella
no effect
reduced with increase in cone.
no decrease
inhibition of growth
complete inhibition
no decrease
inhibition
inhibition
inhibition
44% inhibition
no decrease
killed cultures
max. tolerance limit
max. tolerance limit
no effect
Effective concentration to control 50% of algal population
Effective concentration to control 50% of algal population
growth allowed
inhibition
increase dry weight
no metabolism
inhibited Chlorella, not Euglena
61% reduction in lipid biosynthesis
toxic
inhibition
total suppression
metabolism
inhibition of growth
elimination
reduction
NY 612
Herbicide
Insecticide
Insecticide
Herbicide
Herbicide
Insecticide
Fungicide
Herbicide
Herbicide
Herbicide
Herbicide
Herbicide
Fungicide
Insecticide
Fungicide
Herbicide
Herbicide
Herbicide
Herbicide
Insecticide
Herbicide
Herbicide
Herbicide
Herbicide
Insecticide
Insecticide
Herbicide
Herbicide
Fungicide
Insecticide
Herbicide
Herbicide
Herbicide
Herbicide
Insecticide
Fungicide
Fungicide
Herbicide
Herbicide
Fungicide
Herbicide
Herbicide
Fungicide
Herbicide
Fungicide
Herbicide
a Sourced from Butler 1977. b Sourced from Pipe 1992. * These chemicals warrant further investigation for use as
algicides.
2.4
What is available in Australia?
Many chemicals are registered in Australia as algicides, with the majority being registered for swimming
pools (Table 2.2). A number of the copper compounds are registered for general use as algicides or as
fungicides. These will need testing to determine their mobility and potential harm to the environment under
nursery conditions.
Table 2.2 Registered algicides in Australia.
Chemical
benzalkonium chloride
boron
bromine
bromine as bromo-chloro-dimethylhvdantoin (BCDMH)
bromine as sodium hypobromite/bromide
Purpose
pool, spa, timber treatment,
timber treatment,
pool, spa,
general, pool,
pool, spa,
33
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Chemical
calcium sulphate
chlorhexidine complex (vantocil IB)
chlorine
chlorine as bromo-chloro-dimethylhydantoin (BCDMII)
chlorine as calcium hypochlorite
chlorine as sodium dichloroisocyanurate
chlorine as trichloroisocyanuric acid
cobalt sulphate
copper
copper (II) chloride dihydratc
copper as a complex blend of copper salts
copper as copper tetraamine
copper as copper tricthanolamine complex
copper as cupric hydroxy acid complex
copper as organic complex
copper oxychloridc
copper sulphate
cupric hydroxide
dadmac cationic flocculcnt
dichlorophen
EDTA
ferrous sulfate heptahydrate
hydrogen peroxide
inert ingredients
lithium hypochlorite
mancozeb
nickel as nickel sulfate
poly (hexamethylene biguanide) hydrochloride
poly oxyethylene (dimethyliminio) ethylene (dimethyl...)
potassium permanganate
quaternary ammonium chloride
simazine
sodium hypochlorite
sodium hydroxide
sulfur-element-crystalline
tin
tin as sodium stannate
triethanolamine
NY 612
Purpose
trough
pool, spa
pool. spa.
general, pool
pool, spa,
pool, spa,
pool. spa.
trough
general, pool. spa. paths, turf.
pool
pool
pool
pool.
pool
fungicide.
fungicide,
general, fungicidal spray, pool,
fungicide.
pool
fungicide, bactericide.
pool
herbicide, fertiliser,
pool. spa.
pool
pool
fungicide, turf.
pool
pool, spa
pool. spa. fungi and bacteria control pesticide.
pool
pool. spa. timber treatment
fish pond, pool, aquarium, general
pool, spa.
pool
fungicide.
pool
pool
pool
This table was compiledfrom the Chemical Registration Information System 1996.
2.5
Concluding remarks on algae.
Many chemicals have been tested as algicides but their effectiveness and usefulness in the Australian nursery
industry is unknown (Bodman 1996). Conflicting reports, the use of algicides in situations apart from
nurseries and lack of information in some reports make the choice of an appropriate treatment difficult.
2.5.1
Chemicals tested as algicides
BCDMH could have potential use as an algicide in the Australian nursery industry, however, testing is
needed to determine its effectiveness under Australian conditions. The literature cited for Alginex"
(quinonamid) gave conflicting results. This chemical would need testing in Australian conditions to
determine its effectiveness in nurseries. Algizit® had phytotoxic effects on several plants and no doubt will
be phytotoxic to a range of other plants, but it may have potential use on paths, benches and greenhouse
structures if drift onto plants is controlled. The limited information presented on BAS 278 15D indicates that
this unspecified chemical could be a useful algicide in nurseries. Brestan" was tested under laboratory
conditions and worked well as an algicide but its usefulness in nurseries is unknown.
A copper compound, CA 9213, prevented algal growth in nurseries but did not destroy existing algae. This
chemical may have potential use in Australian nurseries as a preventative algicide. Copper sulphate is mobile
and non-biodegradable (James and Beardsell 1995) and it also causes corrosion on greenhouse structures.
The future use of copper sulphate in nurseries needs to be reconsidered. Whether dicopper dihydroxide
34
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
carbonate is effective in nurseries also needs to be tested, however if it is as mobile as copper sulphate, it will
not be suitable.
Cyprex 65WP® gave good algal control on various greenhouse surfaces and could be of potential use in
Australia. Irgagol 1051® would not be safe to use over plants, but has potential for use in non production
areas. The rates of oxidants for the control of algae in nurseries is unknown although a rate for Nylate®
(BCDMH) for the control of algae in irrigation pipes is available (14 ppm) and would need testing on typical
nursery surfaces. Many oxidants such as chlorine react with organic matter and may be ineffective when
applied to potting mixes.
Potassium permanganate is classed as an 'average' algicide when compared to Diuron®, but it was better than
chlorine and hydrogen peroxide. Potassium permanganate was least corrosive to aluminium when compared
with other algicides so should be considered where there are aluminium surfaces. Further investigations
would need to be conducted to determine the place of Thiram® and Maneb® for the control of algae under
Australian conditions. Both fungicides are registered in Australia and could be possible treatments for algal
control in nurseries. Maneb® is well known to the nursery industry and has little phytotoxic effects, yet gave
effective residual control of algae in pots for 3 months (Fischer 1973).
The other algicides may have potential use in Australian nurseries, however, considerable research is
required.
2.5.2
Chemicals with algicidalproperties.
Chemicals from Table 2.2 and elsewhere that show promise as algicides are: benomyl, carboxin, Dipterex,
Dowacide A, fenithrothion, mancozeb, maneb, methiocarb, TEPP and thiram, all of which are fungicides
except Dipterex and fenithrothion which are insecticides. No herbicide was selected due to the potential risk
of phytotoxicity and the possibility that damaging concentrations could be accidentally used.
2.5.3
Chemicals registered as algicides in Australia.
There are a host of chemicals registered as algicides in Australia, many of which are for swimming pools.
Algicides that could be used in the nursery industry are those that are registered as fungicides and those in the
general category. However, many of these are copper compounds which may be mobile in nurseries. The
phytotoxicity of some of the general algicides on plants is unknown. The use of pool algicides in nurseries
requires extensive testing, and these products are generally inexpensive.
Research in nurseries under Australian conditions is required to determine which algicides are effective.
Tests will need to be conducted to determine:
2.6
1.
rates of effectiveness
2.
phytotoxicities
3.
species of algae present and which are controlled
4.
structural damage caused by chemicals
5.
environmental and human friendliness
6.
capital and running costs.
References
Anderson, L.W.J, and Dechoretz, N. (1984) Laboratory and field investigations of a potential selective
algicide, PH4062. Journal ofAquatic Plant Management 22: 67-75. (Abstract seem).
Barthakur,B.K.; Dutta, P., Karan-Singh and Singh, K. (1992) : Clonal susceptibility of red rust: Two-and-aBud. 39: (2) 52.
Bodman, K. 1996. Algae control in wet production areas. Flower Link 14:(157) 6-8.
Butler, G.L. (1977) Algae and pesticides. Residue Reviews 66: 19-62.
35
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Chase, A.R. and Osborne, L.S. (1987) Cyprex 65 WP controls algae on some greenhouse surfaces. Foliage
Digest 10:(7) 8. (Abstract only)
Chemical Registration Information System (1996) Department of Natural Resources and Energy Chemical
Database, Dec20, 1996.
Coosemans, J. and Vanachter, A. (1995) Control of algae in hydroponic systems. Acta Horticulturae 382:
263-268.
Dalvi, M.N.; Sardeshpande, J.S. (1993) Studies on red rust disease of mango. Journal-of-MaharashtraAgricultural-Universities. 18: (2) 199-201.
Ferrante, G.M. and Viterbo, A.B. (1974) Agar plate technique for potential algicide screening. Riso 23:(1)
13-18. (Abstract seen).
Fischer, P. (1973) The control of algae on the surface of sand beds. In Fritzsche, G (1973). Clay pots without
algal growth and greening. Erwerbsgartner 27: 295-296. (Abstract seen).
Geiger, R.W., Guehler, P.F. and Paterson, W.G. (1973) A new algicide for filamentous algae and Chara,
Abstracts, 1973 Meeting of the Weed Science Society of America, Atlanta, Georgia 39. (Abstract
only).
Goodwin, S. and Steiner, M. (1996) Watch out for fungus gnats and shore flies. Australian Horticulture
March, pp 35-37.
Hartz, P. and Schumacher, H. (1975) Quinonamide - use against algae and moss in the glasshouse and field.
Mitteilungen aus der Biologischen Bundesanstalt fur Land und Forstwirtschaft 165: 224. (Abstract
only).
Hemer, M. (1980) Algae and moss. Experiences and experiments on control. Gartenetl + Gw. 80:(3) 53-54.
(Abstract only).
Hickman, G.W. and Viss, T. (1989) Research on a bromine disinfectant for greenhouses. Flower and Nursery
Report for Commercial Growers, Spring pp 3-4. (Abstract only)
Himme, M. van, Stryckers, J. and Bulke, R. (1984) Flower Crops. Mededelingen van het Centrum voor
Onkruidonderzoek van de Rijsuniversiteit Gent. 40: 128-142. (Abstract seen).
Hornis, A. and Rober, R. (1981) Control of algae in hydroculture. Means and methods. Deutscher Gartenbau
36: 2162-2164. (Abstract seen).
James, E.A. and Beardsell, D.V. (1995) Final report on nursery recycled water. Part 2: Water quality survey.
Recycling water in the Australian nursery and flower industries:
Managing water quality and
pathogen disinfestation. Final report for HRDC Project No. NY320, The Institute for Horticultural
Development, Knoxfield VIC.
John, D.M. (1988) Algal growths on buildings: a general review and methods of treatment. Biodeterioration
Abstracts!: 81-102.
Kaniuka, R.P. (ed) (1974) Viruses for control of algal blooms, Agricultural Research, USA 23:(2) 15.
Kong, I., Bitton, G., Koopman, B. and Jung, K. (1995) Heavy metal toxicity testing in environmental
samples. Reviews of Environmental Contamination and Toxicology 142: 119-147.
Netherlands, Proeftuin Lent (1979) Clean pots O.K., but how? Vakblad voor de Bloemisterij 34:(25) 43.
(Abstract only).
Pawuk, W.H. (1983) Fungicide control of algae in containers. Tree Planters Notes Alaska 34:(4) 5-7.
36
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Pipe, A.E. (1992) Pesticide effects on soil algae and cyanobacteria. Reviews of Environmental Contamination
and Toxicology 127: 95-170.
Powell, C.C. and Shumard, K.J. (1984) The chemical control of algae on subirrigation mats in greenhouses.
Ohio Florists' Association Bulletin 652: 5-6. (Abstract seen).
Powell, C.C. and Smith, S.A. (1989) The use of Agribrom on cyclamen. Ohio Florists' Association Bulletin,
716: 1-3.
Prescott, G.W. (1969) The Algae a Review, Thomas Nelson and Sons Ltd, London, UK.
Ross, R.L.M. and Puritch, G.S. (1981) Identification, abundance, and origin of moss, liverwort, and algal
contaminants in greenhouses of containerised forest nurseries. Canadian Journal of Forest Research,
11:356-360.
Schietinger, R. (1975) Algae and mosses - a report on their control, Gesunde Pflanzen, 27: 11, 231-234.
(Abstract seen).
Schwemmer, E. (1981) Hydroculture control of algae in containers. Gb + Gw. 81:(38) 864-865. (Abstract
seen).
Sharma, D.D. (1991) Occurrence of Cephaleuros virescens, a new record of leaf-curl in litchi (Litchi
chinensis). Indian-Journal-of-Agricultural-Sciences. 61: 446-448.
Sukenik, A , Teltch, B., Wachs, A.W., Shelef, G., Nir, I. and Levanon, D. (1987) Effect of oxidants on
microalgal flocculation. Water Research 21:(5) 533-539.
Tayama, H.K., Zrebiec, V. and Smith, R.E. (1986) A new biocide/disinfectant for the floriculture industry.
Ohio Florists' Association Bulletin 685: 1-3.
Tubea, B.I. (1979) The effects of nutrient, pH and herbicide levels on algal growth, Dissertation Abstracts
International, B 40: (10) 4596.
Wilde, E.W. and McLaughlin, B.D. (1981) Selecting an algicide for use with aluminium alloys. Water
Research 15: 1117-1124.
Yamamoto, K. and Kurumazuka, N. (1986) Preventive measures for lichens and algae on stone objects.
Scientific Papers on Japanese Antiques and Art Crafts 31: 92-100. (Abstract seen).
Young, R.E. and Stricklin, D.K. (1982) Stacker and cleaner for movable tables in greenhouses. Transactions
of the American Society of Agricultural Engineers 25:1154-1159.
37
Surface Disinfestation of Plant Pathogens for the Nursery Industry
CHAPTER 3
3.1
NY 612
MOSSES AND LIVERWORTS
Introduction
Mosses and liverworts in nurseries tend to colonise the drainage holes and the soil surface of potted
ornamentals. Not only does this interfere with pot drainage and water movement, but it also causes problems
with purchasers, increases detailing costs and makes nurseries look untidy and provides a refuge for pests
and pathogens (Goss 1983).
Control of mosses and liverworts should increase the yield and quality of potted plants. In a two year study
by Sohlberg and Bliss (1987), the effect of moss removal on vascular plant growth in an artic region was
examined. It was found that the above-ground reproductive parts of flowering Ranunculus sabinei were
significantly larger for individuals that had the moss removed compared with control plots. Moss removal
from plots of Papaver radicatum also had significantly larger above-ground, non-reproductive biomass than
individuals in control plots. It was concluded that moss removal resulted in warmer and more aerated soil.
In another study, Montoya et al. (1972) reported an increase in citrus yield of up to 54.8% in the season
following chemical control of mosses, algae and lichens. The results demonstrate the benefits of moss
control and the negative effect of mosses on plant growth.
The following chapter reviews the literature on the common mosses and liverworts inhabiting turf and
nurseries and discusses control practices.
3.1.1
Definition and life cycles
Mosses and liverworts are non-vascular land plants. In both groups, there is an alternation of generations
between a haploid leafy plant (the gametophyte) which bears the sexual reproductive organs and a diploid
structure (the sporophyte) which arises from the leafy plant and produces the spores (Catcheside 1980).
The moss gametophyte is almost always leafy, with small, simple leaves. The plants may appear tufted or
creeping. The leaves are in three rows, spirally arranged around the stem. In the creeping species, the leafy
branches of the moss appear flattened. At maturity, the moss sporophyte is often yellowish or brownish and
bears a sporangium or capsule near their tip. The gametophyte is photosynthetic, providing mature
sporophytes with food (Raven and Johnson 1992).
There are few mosses for which their life cycle is known in detail. Time and method of fertilisation; rate of
growth, plant longevity; and relative importance and method of reproduction are a few of the specific details
not fully understood (Scott and Stone 1976).
The gametophytes of the liverworts grow flat along the ground and are relatively simple. They have a
growing point at one end, where cell division occurs, continuously adding to the length of the plant. Other
liverworts have simple leaves, stems and rhizoids. Their sporophytes are often unstalked and more or less
spherical and are usually held within the gametophyte tissue until their spores are shed (Raven and Johnson
1992). Mosses are found where there are high levels of nitrogen. Wet sites encourage the growth of mosses
and liverworts.
3.1.2
Species
A number of mosses and liverworts have been identified in the literature as colonising ornamental plants and
turf. Table 3.1 lists the mosses and liverworts identified.
Table 3.1 Species of moss and liverwort colonising ornamental plants and turf.
Moss
Acrocarpous sp. (turf)
Brachythecium nilabulum (turf)
Bryum argenteum
Calliergonella cuspidata (turf)
Dicranella rubra
Funaria hygrometrica
Reference
Brauenefa/. 1986
Kuttrufi"1982
German Federal Republic 1974. Hyrycz 1979. Atkinson et al. 1980
Kuttruffl982
Schietinger I975A
Scheitinger 19756
38
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Moss
Funaria sp
Hylocomium squamosum (turt)
Hypmtrn cupressiforme (turf)
Leptobrynm pyriforme
Leucobryum glaucum
Mnium affine (turf)
Oxyrrhynchium praelongum (turf)
I'hyscomitrium piriforme (ground)
Polytrichum commune
Polytrichum sp
Rhytidiadelphus squarrosus (turf)
Tillandsia recurvata
Liverwort
Warchantia sp.
Marchantia polymorpha
Sphaerocarpus terrestris
3.1.3
NY 612
Reference
German Federal Republic 1974
Alfnes 1976a
Engelke and Lichte 1981
Ryan 1983
Looman e/a/. 1993,
Engelke and Lichte 1981
KuttrutT1982
Mel'nik 1974
Looman et at. 1993
Ndon 1986
Kuttruff 1982. Engelke and Lichte 1981
Johnson and Halliwell 1973
German Federal Republic 1974
Looman et al. 1993, Schietinger 19756, Himme et al. 1982, Ryan 1983, Engelke
and Lichte 1981, Himme et al. 1983
Sanftleben 1978
The moss and liverwort problem
Mosses and liverworts block the drainage holes and the surface soil of container plants, interfering with water
movement and causing waterlogging (Goss 1983). High moisture levels in nurseries provide mosses with the
ideal conditions for growth, development and sexual reproduction. Removing this water supply will not
control the problem as mosses can withstand prolonged periods of drought (Raven and Johnson 1992).
3.2
Control methods
3.2.1
Cultural and mechanical
Manual removal of mosses and liverworts from surfaces is a time consuming and labour intensive activity.
Plant roots are exposed when mosses and liverworts are removed from the surface of pots. Containers sitting
in poorly drained areas are most likely to become colonised by mosses and liverworts, although other plants
are colonised where watering frequencies are high. To avoid water puddling, Goss (1983) suggested the use
of raised benches or coarse gravel to improve drainage. Wire mesh or metal benches with drainage holes are
suitable benches. A layer of 10-20 mm gravel with a minimum depth of 5 cm placed on sloped concrete,
bitumen or black plastic, or 10 cm deep gravel placed directly onto compacted road base will provide free
drainage from containers.
Engelke and Lichte (1981) found that moss species in lawns and turf are best controlled by increasing soil
pH. The moss Hypnum cupressiforme was reported as only growing well in soils with a pH of 4.3-6.1,
however, changing the pH of media may not be a viable option in ornamental plant production if neutral to
alkaline conditions are required.
Composted town refuse has been used in conjunction with herbicides and fungicides to control mosses in pots
of Platanus acerifolia. Himme et al. (1980) reported that a 5 cm mulching layer of compost largely
prevented the development of mosses. The spread of moss was also reduced when P. acerifolia in 10 litre
pots was grown on a substrate of composted town refuse, tobacco compost, or a mixture of the two, rather
than when grown in a conventional medium (Stryckers et al. 1979). Similar results were achieved with
containers with a mulching layer of pulverised bark (Himme et al. 1977).
3.2.2
Chemicals and rate of application
The following is information collated from literature on chemicals used to control mosses and liverworts.
Where available, information is given on chemical rates, phytotoxicity to plants and treatment success.
Binapacryl (Acricid )
Acricid" concentrate at 4 g/m gave effective control of liverwort in ornamental pots. Acricid" concentrate
caused flecking in Anturia spp. (German Federal Republic 1975). Efficacy was confirmed by Leiber and
Hahn (1975a) where Acricid" gave very good liverwort control but was poorly tolerated by plants.
39
Surface Disinfestation of Plant Pathogens for the Nursery Industry
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Liverworts, but not mosses were effectively controlled by an application of 1.5-2 g/m of binapacryl (Himme
and Stryckers 1981). Acricid® was discontinued by Hoechst AG in 1987 (Sine 1991).
Binapacryl (Acricid® ) + Mancozeb (Dithane Ultra® )
Used on potted azaleas for the control of liverwort at a rate of 8 g in 1.5 L water/m , the chemical gave
control for fourteen weeks (German Federal Republic 1975).
Binapacryl (Acricid® ) + Dichlorfluanid(Euparen® )
Mosses and liverworts were controlled for three months with a spray containing 4 g Acricid" and 9 g
Euparen®/1.5 L water/m . Leiber and Hahn (19756) found that the growth of Azalea spp. and Erica spp.
could be temporarily inhibited by this treatment. Stryckers et al. (1979) found that dichlofluanid + binapacryl
at a rate of 3 g + 1.5 g/L at 5 L/m gave good control of moss.
Captafol
Captafol was used to treat moss on tea trunks and branches at a concentration of 0.5%. Ronoprawiro (1976)
observed no adverse symptoms but efficacy data was not reported.
Captan
Captan at 5-15 g/m gave good control of mosses and the liverwort Marchantia polymorpha (Himme and
Stryckers 1981). Haglund et al. 1981 found that captan at 36.3 kg + 9.5 L surfactant X77 in 950 L water over
929 m2 gave good control of moss in styrofoam blocks. When treatments were made in cool, cloudy weather
(15.6-18.3°C) there was no injury reported on conifer seedlings, but unacceptable injury occurred at higher
temperatures (26.7-32.2°C; Haglund et al. 1981).
Chlorbromuron (Maloran®)
Chlorbromuron at 75 and 150 g/1000m2 was found to control the moss Hylocomiun squarrosum in lawns
without a phytotoxic effect (Alfines 1976a). Maloran® at 1.5 and 3 kg was sprayed on newly-potted plants
of Acer palmatum, Cotoneaster sp., Magnolia stellata, Pyracantha sp. and a range of conifers. Immediately
after treatment, the plants were sprayed down with water. By the end of the season the pots were completely
free from moss. Caron and Rijswijk (1971) found that the higher rate of treatment caused considerable
damage to Cotoneaster sp. while Acer palmatum, M. stellata and Pyracantha sp. also showed some
phytotoxic responses.
Chloroxuron (Tenoran®)
For use against moss and liverwort
Goss (1983) suggested the use of Tenoran® at the rate of 6 kg/ha for the control of liverwort infestation and
the prevention of mosses and algae. Chloroxuron at 0.3 and 0.4 kg/lOOOm controlled the liverwort,
Marchantia polymorpha and the moss, Funaria hygrometrica in pot grown plants (Alfnes 1976a). Looman et
al. (1993) reported that liverwort and moss growth was suppressed for two months after application of
chloroxuron at 2.0 or 4.0 kg a.i./ha.
For use against liverwort
Sanftleben (1978) used chloroxuron for the control of a liverwort plague. The study found that the chemical
should not be applied if rain is imminent, as the chloroxuron acts as a nitrogen source which favours
liverwort growth. Tenoran® at 7 kg product/ha applied with 200 ml water/m was found to give good control
of liverwort in potted azaleas for 14 weeks. Tenoran however, caused foliage damage of azaleas and
suppressed new shoots (German Federal Republic 1975).
For use against mosses on lawns
Tenoran® (chloroxuron 50%) at 5-6 kg/ha gave good control of moss in lawns for up to a year (German
Federal Republic 1973a). Kuttruff (1982) used chloroxuron at 0.4 or 0.6 g/m2 on two turf mixtures to treat
moss colonies. The chemical was applied to a turf with 20% Agrostis tenuis, 10% Poa pratensis and other
40
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
species, and another turf with 10% P. pratensis, 9% A. tenuis and other species. Control was effective when
the weather was warm and when there was rainfall (Kuttruff 1982).
Treatment with chloroxuron at 350 and 700 g/1000m2 controlled the moss Hylocomium sp. in lawns without
injury to the grass (Alfines 1976a).
For use against mosses in container plants
Chloroxuron at 2.24 kg/ha either alone or followed by lenacil at 2 kg/ha was effective against the moss
Funaria hygrometrica in container grown nursery stock (Himme et al. 1977). Boer (1973) reported that
chloroxuron sprayed on carnations (Dianthus caryophyllus) at 5 kg/ha killed moss and gave good selective
weed control.
Chloroxuron 50% at 70 g/100m2 was sprayed on container-grown Juniperus sp., Thuja sp. and Pinus sp.,
effectively killing moss without injury to the plants (German Federal Republic 19736).
Caron and Rijwijk (1971) applied Tenoran at 4 and 8 kg product/ha on newly-potted plants of Acer
palmatum, Cotoneaster sp., Magnolia stellata, Pyracantha sp. and a range of conifers. Immediately after
treatment, the plants were sprayed down with water. By the end of the season the pots were completely free
of moss. Only Cotoneaster sp. showed signs of leaf scorch at the higher rate of treatment. Himme et al.
(1980) used two applications of chloroxuron at 25 g/100m2 applied two months apart on Platanus acerifolia
to obtain good control of moss.
Good moss control was achieved with a repeated application of chloroxuron at 3.5, 2.5 and 2.5 kg/ha on
container grown plants. No damage was observed in Cotoneaster dammeri, Liriodendron tulipifera and St.
Julien A plum rootstock budded with Prunus triloba (M-GD 1981).
Tenoran was discontinued by Ciba-Geigy Ltd (Sine 1991).
Copper oxychloride (Cobox®, Cupravit")
Montoya et al. (1972) found that Cobox® provided effective control of epiphytic mosses, algae and lichens on
citrus. Addition of Dithane M45 to the copper treatment resulted in similar efficacy. Cobox" was
discontinued by BASF AG in 1989 (Sine 1991).
Copper sulphate
Copper sulphate was suggested by Goss (1983) for use on containers, pathways and bare ground to control
mosses and algae although a rate was not provided. Caution was given for use of copper sulphate on
containers due to its potential phytotoxic effects.
Cryptocidal soap (unspecified active ingredient)
Cryptocidal soap has been found to be an effective treatment in the control of mosses and liverworts but
requires periodic treatment to maintain control (Ryan 1983).
Delagol (unspecified active ingredient)
Delagol at 2 and 5% in 200 ml water/m2 was reported to give good control of liverwort in potted azaleas for
14 weeks (German Federal Republic 1975). Delagol at 3% showed similar activity to Maneb at 2% for
control of moss and liverwort. Maneb gave good control of mosses but less satisfactory control of liverwort
(Marchantia sp.) ( German Federal Republic 1974).
Dinoseb acetate (Aretit®)
Sand-covered benches in a glasshouse sprayed with Aretit® at 70g product/lOOm in 7 litres water suppressed
algae and moss for up to 10 weeks. Two days after treatment, pots containing Ardisia sp., Bromelia sp,.
Camellia sp. and Saintpaulia sp. could be placed onto benches without phytotoxic effects (Leiber and Hahn
19756). Aretit® was discontinued in 1987 by Hoechst AG (Sine 1991).
Diuron (AA Karmex®)
Diuron granules at 0.8 kg a.i./ha was found to be effective against liverwort for at least four months but moss
was not controlled Looman et al. (1993).
41
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Caron and Rijswijk (1971) sprayed AA Karmex® (diuron 80%) at 1 and 2 kg/ha on newly-potted plants of
Acer palmatum, Cotoneaster sp., Magnolia stellata, Pyracantha sp. and a range of conifers. The plants were
sprayed down with water immediately after treatment. At the end of the season, the pots were completely
free from moss. It was found that the higher rate of treatment caused considerable damage to Cotoneaster sp.
and Acer palmatum, M. stellata and Pyracantha sp. were also susceptible.
In an orchard treated with different herbicides, it was found that Bryum argenteum moss appeared on all plots
except those that were treated with diuron, however, rates of application were not specified (Hyrycz et al.
1979).
Dodine acetate
High rates (unspecified) of dodine acetate were effective against liverwort (Ryan 1983).
Dinobuton (Drawinol S®)
Drawinol S® applied at 8 g/m2 was effective against moss and liverwort (German Federal Republic 1975).
Endothall (Endothal®)
Endothal® at 1.25 kg/ha applied on turf provided nearly 100% control of acrocarpous (mat-forming) moss
(Brauene?or/. 1986).
Fentin acetate (Brestan®) + maneb
This chemical caused some ornamental crop damage when used to control moss and liverworts (German
Federal Republic 1974).
Ferric sulphate
Ferric sulphate (rate unspecified) applied as a drench, controlled moss and liverwort but was found to cause
injury to the leaves of Rhododendron cv. Anne Rose Whitney, Cannon Double (azalea) and Photinia fraseri
(Ryan 1983).
Ferrous sulphate
Mosses in two different turfs were treated and controlled with ferrous sulphate at 50g/m (Kuttruff 1982).
Alfnes (1976a) used ferrous sulphate at 20 kg/1000m2 on lawns to control the moss Hylocomium squarrosum
without phytotoxic effects.
Glyphosate isopropylamine salt
Ronoprawiro (1976) used glyphosate (rate unspecified) to control moss on the soil surface of a tea plantation.
Copper hydroxide (Kocide 101®)
Kocide 101® at 4-8 lb/100 gal water (1.8-3.6 kg/454.5 L water) gave good control of Tillandsia recurvata
(ball moss) on evergreen Quercus virginiana (Johnson and Halliwell 1973).
Lenacil (Ban-Hoe®)
Lenacil at 100 g/1000m2 controlled Marchantia polymorpha in pot grown plants (Alfines 19766). At 150
g/1000m2 Lenacil was found to control the moss Hylocomium squarrosum in lawns without injury to grass
(Alfines 1976a).
Linuron (Afalon®)
Afalon® was reported to have caused some ornamental crop damage when used, at an unspecified rate, for the
control of moss and liverwort (German Federal Republic 1974).
Linuron + monolinuron (Afarin®)
Linuron + monolinuron granules at 1.0 or 1.5 kg active ingredient effectively controlled liverworts for at least
four months but did not control mosses (Looman 1993).
42
Surface Dis infestation of Plant Pathogens for the Nursery Industry
NY 612
Maneb
Maneb 2% at a rate of 2 litres/m2 controlled the mosses Bryum argenteum and Funaria sp. The chemical's
activity against liverworts was less satisfactory (German Federal Republic 1974).
Oxadiazon
Oxadiazon at 2.25 kg/ha sprayed on container grown nursery stock failed to control the moss Funaria
hygrometrica and proved highly toxic to Erica hybrida, Calluna vulgaris and Hydrangea (Himme et al.
1977). Ryan (1983) used oxadiazon (rate unspecified) to control moss {Leptobryum pyriforme) and liverwort
(Marchantia polymorpha), but found that under conditions of frequent watering and high humidity, plant
foliage did not dry sufficiently after herbicide application, causing plant injury.
Paraquat (Gramoxone®)
Gramoxone* applied at 9 ml/L water or 4.5 ml/L water, controlled the growth of moss and liverworts in
Pinus contorta seedlings. Powell (1975) reported that one month after treatment 85% of the mosses and
100% of the liverworts had been killed and little regrowth occurred within the next seven months.
Phenmedipham (Betanol®)
Betanol" was used by Sanftleben (1978) in the control of a liverwort plague, however, efficacy data was not
reported.
Quinonamid (Alginex® Chinonamid®)
Sanftleben (1978) reported that quinonamid affects the assimilating process of algae and mosses and destroys
their chlorophyll. Chinonamid® at 1.0-1.5% had a rapid effect on mosses and liverworts, but residual action
was found to be poor (Himme and Stryckers 1981).
Quinonamid at a rate of 3-8 g product/m2 controlled liverwort in ornamental pots (German Federal Republic
1975). Applications of 2-5 g/m" gave some control of algae, liverworts and mosses in potted ornamentals
(Schietinger 1975a).
At the rate of 2-5 g product/m , quinonamid effectively controlled algae, liverwort and moss in horticultural
situations. The liverwort Marchantia polymorpha was reported to be difficult to control. Schietinger (1975b)
found the moss Dicranella rubra was less susceptible to quinonamid than Funaria hygrometrica. Anthurium
(Anthurium sp.), rhaphidophora (Rhaphidophora sp.), several geraniums (Pelargonium spp.) and bromelia
(Bromelia spp.) were tolerant of the chemical although some leaf flecking was evident.
Quinonamid at 5 g/m sprayed on to potting media containing Ardisia, Anthurium, Bromelia and Saintpaulia
spp. prevented colonisation by moss and algae for up to six months without damage to the ornamentals
(German Federal Republic 1975).
Quinonamid at 10 g/L in IL of water/m2 on conifers or at 5-6 g/m2 on Indian azalea gave good control of
liverworts and mosses. Quinonamid caused a slight transient injury to Indian azalea cv. Ambrosiana (Himme
etal. 1980).
Simazine®
Moss, Physcomitrium piriforme colonising an apple orchard has been found to be resistant to simazine .
Moss began to die off during a dry year but re-colonised during a wet year in areas where simazine" residues
were present (Mel'nik 1974). Boer (1973) reported that simazine use in roses (Rosa spp.) under glass failed
to control moss and gave unreliable weed kill at selective rates.
Thiram®
Ryan (1983) found that high rates of Thiram® were effective against liverworts. Repeat applications of
Thiram at 1.5%-2.5% a.i. in water have been reported to give some control of liverworts (Goss 1983).
Applications of Thiram® between 5 and 15g/m2 effectively controlled mosses and liverworts including
Marchantia polymorpha (Himme et al. 1983, Himme and Stryckers 1981)
Thiram" at 16g/L inl.5L water/m , applied to Chamaecyparis lawsoniana columnaris, Chaenomeles japonica
and various conifers or at 20 g/m on Thuja plicata and Indian azalea controlled Marchantia polymorpha and
43
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
other liverworts for 2 to 4 months. These treatments also satisfactorily controlled mosses. None of the
treatments injured the ornamentals (Himme et al. 1980).
Mosses in rooted cuttings of Chamaecyparis lawsoniana columnaris were controlled for up to four months by
Thiram® at 16 g/L in 5 L water/m2 (Stryckers et al. 1979).
Thiram® + Binapacryl
Thiram" + Binapacryl at 5 g + 1 g/m2 controlled Marchantia polymorpha and other mosses in pot grown
Rhododendron simsii under glass. Himme et al. (1982) suggested that the volume of water in which the
chemicals are mixed should not be less than 0.2 and 0.3 L/m2. A treatment of Thiram® + Binapacryl at 5-10
g + 2 g effectively controlled mosses and liverworts including Marchantia polymorpha (Himme et al. 1983).
3.3
Chemicals available in Australia
The chemicals registered in Australia for the control of mosses (Table 3.2) do not reflect the range of
chemicals with proven efficacy and reflects the difficulty in registration of chemicals for minor uses.
Table 3.2. Chemicals Registered in Australia for use on moss (Chemical Registration Information System
1996)
Chemical
Benzalkonium Chloride + Boron
Copper
Copper Sulfate - Pentahydrate plus
Sulfur-Element-Crystalline
Dichlorophen
2,2-DPA as the Sodium Salt plus
Amitrole plus Simazine
Fatty Acids
Ferrous Sulfate
Ferrous Sulfate Heptahydrate
Iron
Iron as Ferrous Sulfate
Sulfur-Element-Crystalline
Sulfur as Elemental Sulfur
3.4
Trade Name
Boracol 100RH Fungicide
Cuprine Plus Path Free Algicide
Bunnings Algae and Moss Destroyer
Turf Free Algaecide
Top Copper Sulphate (Bluestone)
Kendon Kendocide 480 Algicide and Bactericide
Yates Once A Year Pathweeder
Defender Bio Speedweed Weedkiller
Hortico Combined Mosskiller and Lawn Food
Maxicrop Moss Killer and Lawn Tonic
Betta Grower Moss Control Herbicide
Topsol Liquid Iron Fertilizer Ferrosol
Bunnings Lawn Food Plus Moss Kill
Yates Sulphate Of Iron
Combined Moss Killer and Lawn Food
J.C. and A.T. Searle Pty Ltd Sulphate of Iron (Ferrous Sulphate)
Manutec Garden Care Products Moss Killer and Lawn Food
Farm Oz Wettable Sulphur Fungicide
Riverland Horticultural Traders Vinsul Fungicide Miticide
Thiovit Dry Flowable Sulphur Fungicide and Miticide
Summary
There has been extensive research on the control of moss and liverworts on ornamentals. It is evident,
however, that there are many areas that still need to be covered in greater detail. A majority of the literature
is lacking in specific information on the efficacy of cultural or chemical control methods on mosses and
liverworts in plant nurseries. The literature has presented a wide range of chemical rates without identifying
appropriate application rates for control. Contradictions exist between the reported results of chemical
treatment. For example, according to Looman et al. (1993) diuron granules (0.8 kg a.i./ha) did not control
moss in their trials but Caron and Rijswijk (1971), in their work obtained control of mosses when treated at
0.8 kg a.i./ha . Most of the research occurred during the 1970s with chemicals that are no longer available.
Future research should identify the efficacy of control methods, identify appropriate chemicals and
application rates for use in Australia. Current information on the control of mosses and liverworts will
benefit the horticultural industry with increases in production, reductions in production and detailing costs,
and clean, hygienic nurseries and more satisfied customers.
44
NY 612
Surface Disinfestation of Plant Pathogens for the Nursery Industry
3.5
References
Alfines, A.T. (1976a) Moss control in lawns, [Review of Weed Research 1975. 4 Conference on Plant
Protection] Synspunkter omkring Ugrasforsoekene. 4 Informasjonsmoete i Plantevern., Statens
Plantevern Ugrasbiologisk Avdeling/Middelkontrollen, Vollebekk, Norway.pp 105-107. (Abstract
seen).
Alfines, A.T. (19766) Weed control in nursery crops, Review of Weed Research 1975. . 4
Conference on
Plant Protection. pp99-104 (Abstract seen).
Atkinson, D., Abernethy, W. and Crisp, CM. (1980) The effect of several herbicides on moss establishment
in orchards. Proceedings 1980 British Crop Protection Conference - Weeds pp297-302.. (Abstract
seen).
Boer, W. den (1973) Application of herbicide to horticultural crops under glass. Informatiereeks, Proefstation
voor de Groenten en Fruitteelt onder Glas te Naaldwijk 22 pp22,30. (Abstract seen).
Brauen, S.E., Goss, R.L., Nus, J.L. (1986) Control of acrocarpous moss with endothal. Journal of the Sports
Turf Research Institute, 62: 138-140. (Abstract seen).
Caron, J.E.A. and Rijswijk, J. (1971) The control of moss in potted ornamentals. Jaarboek, Proefstation voor
de Boomkwekerj pp 115-117. (Abstract seen).
Catcheside, D.G. (1980) Mosses of South Australia, Handbooks Committee, South Australian Government
SA.
Chemical Registration Information System (1996) Department of Natural Resources and Energy Chemical
Database, Dec. 20, 1996.
Eangelke, R and Lichte, H.F. (1981) Herbicides for moss control. Gesunde Pflanzen, 33:10 (Abstract seen).
German Federal Republic, Biologische Bundesanstalt fur Land und Forstwirtschaft (1973a) Annual Report of
the German Plant Protection Service, Braunschweig, 19 Jg. p. 139. (Abstract seen).
German Federal Republic, Biologische Bundesanstalt fur Land und Forstwirtschaft (19736) Annual Report of
the German Plant Protection Service, Braunschweig, 19 Jg. pp 133-135. (Abstract seen).
German Federal Republic, Biologische Bundesanstalt fur Land und Forstwirtschaft (1974) Annual Report of
the German Plant Protection Service, Braunschweig, 21 Jg. pp 221-223. (Abstract seen).
German Federal Republic, Biologische Bundesanstalt fur Land und Forstwirtschaft (1975) Annual Reports of
the German Plant Protection Service, Braunschweig, 22 Jg. pp 153-157. (Abstract seen).
Goss, O.M. (1983) Practical Guidelines for Nursery Hygiene. Australian Nurserymen's Association,
Parramatta NSW.
Haglund, W.A., Russell, K.W., Holland, R.C. (1981) Moss control in container-grown conifer seedlings. Tree
Planters' Notes 32:3. (Abstract seen).
Himme, M. Van, and Stryckers, J. (1981) Moss control in container- and pot culture of ornamentals.
Mededelingen van de Faculteit Landbouwwetenschappen, Rijksuniversiteit Gent, 46:199-212.
(Abstract seen).
45
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Himme, M. van, Bulcke, R., Stryckers, J. (1982) Weed and moss control in azaleas. Proceedings
International Azalea Seminar, Ghent Belgium 1-14 (Abstract seen).
Himme, M. van, Stryckers, J., Bulcke, R. (1977) Weed control in container grown Chamaecyparis
lawsoniana columnaris Review of results obtained in the cropping years 1975-1976-1977 by the
Centrum voor Onkruidonderzoek.; Bespreking van de resultaten bereikt door het Centrum voor
Onkruidonderzoek tijdens deproefjaren pp 106-108. (Abstract seen).
Himme, M. van, Stryckers, J., Bulcke, R. (1980) Container culture. Review of results obtained for the
cropping year 1978-1979. Centrum voor Onkruidonkerzoek pp 114-118. (Abstract seen).
Himme, M. van, Stryckers, J., Bulcke, R. (1983) Tree nursery crops and amenity areas. Mededelingen van het
Centrum voor Onkruidonderzoek, No.38. 147-160. (Abstract seen).
Hyrycz, K.J., Atkinson, D., Herbert, R.F., White, G.C., Taylor, N., Petts, S.C., Murray, R.A., Knapp, J.G.,
Allen, J.G., and Smith, A.E. (1979) Effects of herbicide management systems on soil conditions.
Report for 1978, East Mailing Research Station, Kent UK. pp 47-48.(Abstract seen).
Johnson, J.D. and Halliwell, R.S. (1973) Compounds for the control of ball moss. Plant Disease Reporter, 57:
81-83.
Kuttruff, E. (1982) Moss control with various compounds, quantities and application dates. Rasen
Grunflachen Begrunungen, 13:59-63. (Abstract seen).
Leiber, E. and Hahn, F. (1975a) The problem of controlling bryophytes in ornamental plant growing.
Gesunde Pflanzen 27:129-132. (Abstract seen).
Leiber, E and Hahn, F. (19756) The problem of moss control in ornamentals. Gesunde Pflanzen 27:129-132
(Abstract seen).
Looman, B.H.M., Kuik, A.J. van, Van Kuik, A.J. (1993) Chemical control of liverwort, moss and weeds in
container-grown nursery stock. Mededelingen
van de Faculteit
Landbouwwetenschappen,
Universiteit Gent 58:837-843. (Abstract seen).
Mel'nik, N.M. (1974) Some changes in the ecosystem of fruit orchard under the influence of simazine.
Zhurnal Obshchei Biologii 35:423-428. (Abstract seen)
M, G.D. (1981) The effect of moss growth and herbicide activity on plant vigour. Verbondsnieuws voor de
Belgische Sierteelt, 25:560. (Abstract only)
Montoya, J., Dongo, S. and Osores, A. (1972) The control of mosses, algae and lichens on citrus in the
Chanchamayo Valley. Proceedings of the Tropical Region, American Society for Horticultural
Science 16:93-106.
Neal, J.C. (1994) Turfgrass Weed Management - An IPM Approach in Handbook of Integrated Pest
Management for Turf and Ornamentals, Lewis Publishers, Bora Raton, Florida, USA.
Ndon, B.A. (1986) Chemical control of inter-row vegetation in oil palm (Elaeis guineensis Jacq.) plantation,
Journal of the Nigerian Institute for Oil Palm Research 7:183-192. (Abstract seen).
Powell, J.M. (1975) Use of Gramoxone to control mosses and liverworts in greenhouse pots. Bi-monthly
Research Notes, 31:35-36. (Abstract seen).
Raven, P.H. and Johnson, G.B. (1992) Biology, 3 rd Edn., Mosby Year Book, Missouri USA.
46
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Ronoprawiro, S. (1976) Control of mosses in tea. Proceedings of 5 Asian-Pacific Weed Science Society
Conference, Tokyo Japan, 1975. pp 365-369. (Abstract seen).
Ryan, G.F. (1983) Moss and liverwort control in ornamentals. Abstracts, 1993 Meeting of the Weed Science
Society of America, pp 38-39. (Abstract seen).
Sanftleben, H. (1978) Liverwort plague in many container plant systems. Deutsche Baumschule 30:196-197.
(Abstract seen).
Schietinger, R. (1975a) Algae and moss - a contribution to their control. Gesunde Pfanzen, 27:231-234.
(Abstract seen).
Schietinger, R. (19756) Algae and mosses - a report on their control. Gesunde Pflanzen, 27:231-234.
(Abstract seen).
Scott, G.A.M. and Stone, I.G. (1976) The Mosses of Southern Australia, Academic Press, London UK.
Sine, C. (1991) Farm Chemicals Handbook '91, Meister Publishing Company, Ohio USA.
Sohlberg, E.H. and Bliss, L.C. (1987) Responses of Ranunculus sabinei and Papaver radicatum to removal
of the moss layer on a high-artic meadow. Canadian Journal of Botany 65:1224-1228.
Stryckers, J., Himme, M. van, Bulcke, R. (1979) Nursery crops: container culture. Review of results obtained
in the cropping years 1976-1977-1978 by the Centrum voor Onkruidonderzoek.: Bespreking van de
resultaten bereikt door het Centrum voor Onkruidonderzoek tijdens de proefjaren pp 161-164. (Abstract
seen).
47
Surface Disinfestation of Plant Pathogens for the Nursery Industry
CHAPTER 4
4.1
NY 612
REMOVAL OF COPPER FROM WATER
Introduction
Copper contamination of the nursery environment occurs when copper containing compounds are added to
plants, soils or surfaces for the control of plant pathogens, algae or mosses. Copper is not readily mobile in
sandy or regolithic soils, travelling approximately 1 m/ 200 years (Geriste et al. 1992). Continued use of
copper compounds in nurseries therefore results in the build up of copper levels in soils and eventual
development of phytotoxicity problems with soil or container grown crops (Goss 1983).
Copper contamination of nursery water occurs when copper containing compounds are applied as
micronutrients, fungicides, bactericides or algicides and when the product is washed or leached from the
target area. James and Beardsell (1995) showed that some nurseries exceed legal copper limits in run-off
water after application of copper based algicides to paths, where a copper concentration of 6.32 mg/L was
recorded on one occasion.
Copper levels in the run-off water were, on occasion, sufficient to cause phytotoxic effects on plants if
nurseries were to recycle the water, and the copper had not been adsorbed prior to re-use. If nursery waste
waters are released into streams, heavy metals such as copper are absorbed by animals in the aquatic
ecosystem but do not seem to bioaccumulate along the food chain (Suedel et al. 1994). Oysters and worms
absorbed most copper due to their filter feeding and sediment ingesting habits respectively. Crabs and
oysters may take up 'luxury' quantities of copper as a physiological requirement for their blood (Suedel et al.
1994). Copper however is toxic to aquatic organisms, where the lethal dose for 50% of the exposed
population (LD50) is 0.25, 0.1 and 0.5 ppm for rainbow trout, fathead minnow and daphnia respectively
(Kong et al. 1995). The LD50 values for the fish and invertebrates are below the recommended levels for
estuaries and the limits for drinking water but above those for irrigation and regional water recommended in
Victoria (James and Beardsell 1995).
A system of removal of heavy metals from water may be adopted in nurseries where levels are high and
where water is recycled to avoid increasing concentrations of heavy metals in water with resultant
phytotoxicity to nursery plants and possible health hazard to nursery workers. Replacements for copper used
in the nursery industry are also necessary to prevent build-up of copper in both soil and water. The
guidelines for safe levels of copper in water are listed in Table 4.1
Table 4.1 Guidelines to the safe and legal levels of copper in water (after James and Beardsell 1995)
Limits in estuaries
1.0 mg/L
Limit for drinking water
1.5 mg/L
NSW Clean Waters Act
1.0 mg/L
Victorian Act (regional)
0.2 mg/L
Limits for irrigation (phytotoxicity)
0.2 mg/L
4.2
Methods for the removal of copper from water
Copper ions form complexes with carboxyl groups of humic materials such as fulvic acid and are thereby
removed from solution (Gamble et al. 1994). The complexing capacity of humic materials however,
decreases with increasing pH. Frank and Dechoretz (1982) found that 50% of copper added to irrigation
water as copper sulphate pentahydrate was sorbed by suspended particulate matter greater than 0.45 microns
in size.
48
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
The removal of heavy metals from water is widely practised for drinking and industrial waste water (Dymke
1995). Heavy metals may be removed by the addition of lime (Dymke 1995), by cation exchange (Eldridge
1995), flocculation with SIRFLOC STP (Booker et al. 1995) or by adsorbtion onto organically derived
materials such as water hyacinth (Gopal et al. 1991), peat (Viraraghavan and Dronamraju 1993) or treated
dead algae as AlgaSORB® (Darnall and Hyde 1989).
If it is necessary, the method of copper removal suggested for the nursery industry will be determined by the
capital and running costs associated with the treatment process. Methods such as addition of lime require
mixing and sedimentation tanks and finally pH correction as the initial lime treatment increases pH to 9.5 to
11 to precipitate heavy metal ions, eg. copper ions, as metal hydroxides. The installation of multiple tanks
and addition of chemicals over a number of stages would not be suitable for small to medium sized nurseries
due to high capital and maintenance and labour costs. The lime assisted removal of copper however utilises
50% smaller primary sedimentation tanks and has a higher loading rate, reducing capital costs compared to
other water treatment systems. The process removes up to 88% of the copper in untreated water.
Ion exchange methods for the removal of metal ions rely on columns of carboxylic acid based resins which
bind to the metallic cations in water flowing through the system. However, when the resin becomes saturated
with metal ions, a breakthrough of metal ions in the water results. The frequency of breakthrough is
dependant on the level of metal contamination and the efficiency of the cation exchange material. Typically,
cation exchange resins need to be regenerated after 300-400 x resin bed volumes of water have been treated
(Eldridge 1995). Cation exchange resins therefore must be regenerated periodically by the addition of acid to
the column. The effluent of concentrated metallic ions must then be disposed of, or the metal may be
regenerated by electrolysis. The advantage of the electrolysis step is that the acid solution is regenerated and
may be re-used to regenerate the resin later. The volume of effluent however is smaller than the volume of
sediment generated by flocculation methods and therefore disposal is relatively cheap (Eldridge 1995). Use
of columns of algal biomass (AlgaSORB®) operate on the same principal as cation exchange resins and must
be regenerated by an acid wash (Darnall and Hyde 1989). Similarly, use of organic materials such as peat
make use of similar cation exchange chemistry and also need to be regenerated periodically.
4.4
References
Booker, N., Kolarik, L.O. and Brooks, R.B. 9195) Sirofloc
processes for rapid treatment of drinking water
and sewage. In Modern Techniques in water and waste water treatment. (Eds L.O. Kolarick and A.J.
Preistley) CSIRO, East Melbourne, pp 25-33.
Darnall, D.W. and Hydye, L.D. (1989) Removal of heavy metal ions from groundwaters using an algal
biomass. In Biotreatment: The use of microorganisms in the treatment of hazardous materials and
hazardous wastes. Proceedings of the 2" National Conference November 27-29 1989 Washington DC pp 4145.
Dymke, J. (1995) Lime-assisted primary treatment of sewerage for suspended solids and heavy metal
removal: an option for staged wastewater treatment process development. In Modern Techniques in water
and waste water treatment. (Eds L.O. Kolarick and A.J. Preistley) CSIRO, East Melbourne, pp 35-39.
Eldridge, R.J. (1995) Wastewater treatment by ion exchange In Modern Techniques in water and waste
water treatment. (Eds L.O. Kolarick and A.J. Preistley) CSIRO, East Melbourne, pp 61-64.
Frank, P. A. and Dechoretz, N. (1982) Fate of copper in irrigation water. Abstracts of the Meeting of the
Weed Society of America 1982, p64.
Gamble, D.S., Langford, C.H. and Webster, G.R.B. (1994) Interactions of pesticides and metal ions with
soils: unifying concepts. Reviews of Environmental Contamination and Toxicology 135: 63-91.
Gerriste, R.G., Adeney, J.A., Baird, G. and Colquhoun, I. (1992) The reaction of copper ions and
hypochlorite with minesite soils in relation to fungicidal activity. Australian Journal of Soil Research 30:
723-735.
Gopal, V., Devi, M. and Gopal, R. (1991) A biological technique of differential depollution of heavy metals
and pesticides. Journal of Ecotoxicology and Environmental Monitoring 1: 250-264.
49
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Goss, O.M. (1983) Practical Guidelines for Nursery Hygiene, Australian Nurseryman's Association,
Parramatta NSW.
James, E.A. and Beardsell, D.V. (1995) Final report on nursery recycled water Part 2: Water quality survey.
Recycling water in the Australian nursery and flower industries: managing water quality and pathogen
disinfestation. Final report for HRDC project No. NY320, The Institute for Horticultural Development,
Knoxfield VIC.
Jodai, S., Onishi, H., Uehara, T. and Goto, T. (1978) Studies on the adsorption of heavy metal on bark Part 3
Removal of copper (II) from polluted river. Bulletin of the Faculty of Agriculture Shimane University,
Japan.lssue 12 :114-116.
Kong, I., Bitton, G., Koopman, B. and Jung, K. (1995) Heavy metal toxicity testing in environmental
samples. Reviews of Environmental Contamination and Toxicology 142: 119-147.
Suedel, B.C., Boracczek, J.A., Peddicod, R.K., Clifford, P.A. and Dillon, T.M. (1994) Trophic transfer and
biomagnification potential of contaminants in aquatic ecosystems. Reviews of Environmental Contamination
and Toxicology 136: 21-89.
Viraraghavan, T. and Dronamraju, M.M. (1993) Removal of copper, nickel and zinc from wastewater by
adsorption using peat. Journal of Environmental Science and Health A28 1261-1276.
50
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Appendix
Appendix 1. The algae reported growing on surfaces associated with man-made
structures.
Adapted from John 1988.
TAXON
CHLOROPHYTA
Chaetophorales
Desmococus olivaceus
Cylindrocapsa spp.
Pleurastrum s spp.
Protoderma spp.
Pseudedoclonium printzii
Chlorococcales
Bracteacoccus spp.
Chlorella
ellipsoidea
vulgaris
species
Chlorococcum
ellipsoideum
species
Coccomyxa spp.
Neochloris terrestris
Neospongiococcum spp.
Oocystis
marssonii
parva
species
Pseudococcomyxa simplex
Scenedesmus spp.
Spongiochloris spp.
Trebouxia spp.
Chlorosarcinales
Borodinellopsis spp.
Chlorosarcina spp.
Chlorosarcinopsis
minor
pseudominor
species
Pseudotrebouxia spp.
Tetracystis spp.
Oedogoniales
Oedogonium spp.
Siphonocladales
Cladophora
glomerata
Tetrasporales
Gloecystis
species
Palmellopsis spp.
Trentepohliales
Trentepohlia
aurea
monilia
odorata
umbrina
species
Ulotrichales
Hormidium
pseudostichococcus
subtilissimum
species
Klebsormidium
flaccidum
species
Microspora spp.
SUBSTRATUM
stone, brick, concrete, limestone walls (often associated with buildings), paint, cement paint or
limewash, asbestos cement roofs, roof tiles, greenhouses, sandstone monuments; probably on
most surfaces
concrete walls
limestone walls and buildings
stone wall
frescoes, marble sculptures
stone walls, limestone walls and buildings
stone walls, limestone and sandstone walls of buildings
stone walls, concrete, limestone and sandstone
stone, concrete, brick and limestone walls (often of buildings), roof tiles, paint, iron rails
asphalt roof shingles
stone walls, concrete, brick and limestone walls, roof tiles, paint, iron rails
limestone walls of buildings
asphalt roof shingles
limestone walls of buildings
limestone walls of buildings
limestone walls of buildings
limestone walls of buildings
frescoes
limestone walls of buildings
limestone walls of buildings
walls, asbestos cement, limestone walls of buildings
limestone walls of buildings
stone walls, paint
asphalt roof shingles
stone walls, paint
limestone walls of buildings
limestone walls of buildings
limestone walls of buildings
stone wall
stone walls
stone walls, iron rails
limestone walls of buildings
stone walls, cement paint
asphalt roof shingles
stone and concrete walls
cement paint
stone, brick and concrete walls (often associated with buildings), roof tiles, paint and limewash
bricks
asphalt roof shingles
concrete walls of buildings
asphalt roof shingles, stone walls, iron rails
limestone walls of buildings
asphalt roof shingles
51
Surface Disinfestation of Plant Pathogens for the Nursery Industry
TAXON
Stichococcus
bacillaris
chodatii
species
Ulothrix
punctta
species
Ulvales
Prasiola
crispa
Volvocales
Chlamydomonas spp.
Eudorina spp.
CHRYSOPHYTA
Mischococcales
Botrydiopsis spp.
Botryochloris minima
Tribonematales
Helerothrix olothrichoides
RHODOPHYTA
Bangiophyceae
Porphyridiales
Porphyridium purpureum
CYANOPHYTA
Chroococcales
Anacystis
marina
montana
thermalis
Agmenellum
quadruplicatum
thermale
Aphanothece
species
Chloroglea spp.
Chroococcus
limneticus
lithophilus
minor
tenax
varius
species
Coccochloris
elabens
Coelosphaerium spp.
Gloeocapsa
dermochroa
compacta
G. helvetica
kuetzingiana
magma
muralis
punctata
rupestris
sanguinea
species
Gloeothece spp.
Gomphosphaeria lacustris
Merismopedia spp.
Microcystis spp.
Myxosarcina spp.
Palmogloea protuberans
Urococcusspp.
Oscillatoriales
Nostocaceae
Nostoc
commune
microscopicum
sphaericum
NY 612
SUBSTRATUM
asphalt roof shingles, iron rails, stone columns and walls, asbestos cement, frescoes, limestone
and sandstone walls of buildings
asphalt roof shingles
limestone walls of buildings
limestone walls of buildings
iron rails
stone walls
fired clay roof tiles, limestone walls and buildings
fired clay roof tiles
stone walls
limestone and sandstone walls of buildings
stone walls
stone walls
walls of buildings with surface of concrete or emulsion paint
concrete walls
concrete walls
stone walls
walls of buildings with surface of concrete or emulsion paint
stone walls
concrete and brick walls ( often associated with buildings), paint and limewash, roof tiles,
sandstone monuments
stone wall
sandstone and concrete walls
stone wall
walls (probably concrete)
stone walls
stone, brick and concrete walls, paint and limewash, roof tiles, asphalt roof shingles
stone walls, concrete and emulsion-painted walls of buildings
stone walls
concrete walls
stone walls
limestone walls of buildings
stone wall
asphalt roof shingles, stone walls
asphalt roof shingles
concrete walls
asphalt roof shingles
concrete and sandstone walls, stone walls
stone, brick and concrete walls (often associated with buildings), roof tiles, paint and
limewash, sandstone monuments
concrete and brick walls (often associated with buildings), roof tiles, paint
stone wall
limewash
fired clay roof tiles
brick and concrete walls of buildings, paint and limewash, roof tiles
stone walls
asphalt roof tiles
concrete or emulsion-painted walls of buildings
stone walls
stone walls
52
Surface Disinfestation of Plant Pathogens for the Nursery Industry
TAXON
species
Oscillatoriaceae
Lyngbya
aerugineo-caerulea
martensiana
species
Microcoleus vaginatus
Oscillatoria
lutea
pseudogeminata
subtilissima
terebriformis
species
Phormidium lignicola
Porphyrosiphon spp.
Schizothrix
calcicola
Jriesii
rubella
species
Spirulina
subsalsa
species
Rivulariaceae
Calothrix
parientina
species
Homeothrix janlhina
Scytonemataceae
Plectonema spp.
Scytonema
hofmannii
myochrous
species
Tolypothrix
byssoidea
species
Stigonemataceae
Stigonema
mesentericeum
minutum
species
Westiellopsis prolifwa
species
NY 612
SUBSTRATUM
stone, brick and concrete walls (often associated with buildings), paint and limewash, roof tiles
and frescoes?
limestone walls of buildings
limestone walls of buildings
concrete walls (often associated with buildings), fescoes
stone wall
concrete and emulsion-painted walls of buildings
limestone walls of buildings
limestone walls of buildings
limestone walls of buildings
stone, bricks and concrete walls (often associated with buildings), paint and limewash, roof
tiles (fired clay)
limestone walls of buildings
sandstone monuments
stone walls, concrete and emulsion-painted walls of buildings
concrete and emulsion-painted walls of buildings
concrete and emulsion-painted walls of buildings
stone walls
concrete and emulsion-painted walls of buildings
concrete walls of buildings
concrete and emulsion-painted walls of buildings
concrete and brick walls of buildings, paint and limewash, roof tiles
stone wall
frescoes
concrete and emulsion-painted walls of buildings
concrete and stone walls
stone, brick and concrete walls (often associated with buildings), paint and limewash, roof
tiles, sandstone monuments
asphalt roof shingles
concrete walls of buildings, sandstone monuments
stone walls
stone walls
stone walls
concrete and emulsion-painted buildings
brick and concrete walls of buildings, paint and limewash, roof tiles
53
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Appendix 2. Table of the efficacy of disinfectants on a range of plant pathogens
Chemical
Agribrom
Pathogen
CyMV, ORSV
Algae
Algae
Algae
"
Chlorine dioxide
Ethanol
Formalin
Heat Autoclave
Erwinia chrysamthemi
Agrobacterium
tumefaciens
Xanthomonas
campestris pv.
dieffenbachiae
Erwinia amylovora
Botrytis cinerea
Fungi
Situation
Pruning tools
Sub irrigation
mats
Walkways
Evaporative pads
Unknown
ToMV
Razor blades and
clippers
Apples
Water
Packinghouse
surfaces, floor,
belts, chutes
Shears
CyMV, ORSV
Pruning tools
CEV
Knife blades
Bacteria
Soil
Fungi
Soil
Thielaviopsis basicola
Sand
Bacteria
Fungi
Soil
Soil
Efficacy
Not controlled at 20%
Controlled at 4-5 ppm
80% control at 800 ppm
3-7ppm/6 months Control
achieved = 7.8 /10 rating
Killed after 1 min at 5ppm
Killed after 1 min at 5ppm
Comments
Not phytotoxic
Slight effect on
Range of ornam
sprayed at lOOpp
phytotoxic
Complete disinfection after
5 sec at 1 OOppm
5ppm/ 20min no control
100% control at 5ppm/2 min
14-18ppm\~45 min,
variable efficacy, depending
on surface
71 %> transmission at70%
70%> failed to inactivate
CyMV
dip in 95%> + flaming failed
to inactivate CEV
24-fold increase after 3.8ml
40% formaldehyde /L soil
3.5-fold increase after 3.8ml
40%) formaldehyde /L soil
Control after drench of 5.5 g
a.i/L
Controlled at 120°C/40 min
Controlled at 120°C/40 min
54
Applied as a foa
2 weeks after tr
2 weeks after tr
50ml/pot
Surface Disinfestation of Plant Pathogens for the Nursery Industry
NY 612
Chemical
Heat Flame
Pathogen
CEV
Situation
Knife blades
Heat Microwave
Bacteria
Soil
Heat
Microwave (cont)
Fungi
Phytophthora
cinnamomi, Fusarium
oxysporum, Rhizoctonia
sp, Penicillium sp.
Fungi
acteria
Soil
On agar
Controlled at 650 W/ 6 min
Fusarium and Penicillium
spp not controlled, others
controlled
5.2% soil moistu
12 sec
Soil-less media,
soil
Soil-less media,
soil
Colonised seed
Controlled after 10 min
exposure
Temperature of 1
Colonised seed
Colonised seed
Soil
15minat55°C
15min at47.5°C
Controlled at60°C/ 30 min
Soil
Controlled at60°C/ 30 min
Soil
Variable control at 60°C/30
min
Controlled >50°C/30 min
Heat, steam
Phytophthora.
cinnamomi
P. citricola
Armiliaria
luteobubalina
Plasmodiophora
brassicae
Synchytrium
endobioticum
Oplidium brassicae
Soil
Heat, solarisation
Cylindrocarpon
destructans
Range of Pythiaciae
Sclerotinia sclerotiorum
S. sclerotiorum
S. minor
Soil
Sclerotes in field
in wet soil
Sclerotes on wet
paper
Efficacy
4-6 sec propane torch flame
failed to inactivate virus
Controlled at 650 W/ 6 min
Controlled at 15min at 45°C
Controlled between 5050°C/30 min
Controlled at 45°C
continuous/28 hr,
15% survived if heated for
8x6hr periods of 45°C
Controlled at 45°C/8hr and
at 50°C/2hr
55
Comments
5.2% soil moistu
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Chemical
Macrophomina phase oli
Macrophom ina phaseoli
Situation
Colonised reed
canes and
Eucalyptus stakes
Soils used for
carnations
Soils used for
eggplant
Soil
Soil
Controlled fungus to a depth
of30cm
Controlled fungus to a depth
of 45cm after
Failed to control fungus
Failed to control fungus
Fusarium oxysporum
Soil
Failed to control fungus
16 days solarisat
Phytophthora
cinnamomi
Pyrenochaeta
lycopersici
Botrytis cinerea
Soil
Soil in glasshouse
Controlled fungus
Significant reduction of
corky root
6 weeks solarisat
Glass
99.9% control after 8 min
exposure to 0.27ppp at 20°C
or 16 min exposure to
0.55ppm at 30°C
1% solution Sanosil"
0.7% solution Sanosil®
99.999% reduction after 90
secdipin35%/40°C
99.999% reduction after 20
exposure to 0.55ppm vapour
at 20°C
Controlled at 1% lodel®/lhr
Vapour
98% disinfection , 2%
Iobac®
As effective as f
10% sodium hyp
Pathogen
Didymella lycopersici
Fusarium oxysporum
f.sp.dianthi
Verttcillium dahliae
Hydrogen peroxide
lodophors (Iodine
containing chemicals)
NY 612
Alternaria alternata
Botrytis cinerea
Bacillus subtillus
Water
Olpidium brassicae
Concrete floors
glasshouse
surfaces
Plasmodiophora
brassicae
Botrytis cinerea
Fusarium culmorum
Contaminated
plastic pots
Polythene
Efficacy
Reduced plants with cankers
from 20.7 to 1.9%
100% control after 15 min
56
Comments
5 months solarisa
day/11-20°C nig
30 days solarisat
30 days solarisat
35 days
63 days solarisat
63 days solarisat
Stabilised with s
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Chemical
Phenol based
compounds
Quaternary
ammonium
compounds
Sodium hydroxide
Pathogen
F. oxysporum
Phoma foeeata
Rhizoctonia solani
Clavibacter
michiganensis. subsp.
sepedonicus
Erwinia carotovora
subsp. atroseptica
Situation
Wood,
metal,
plastic
Wood
Metal
Plastic
CyMV, ORSV
Pruning tools
Thielaviopsis basicola
Phytophthora
cinnamomi
Fusarium oxysporum
f.sp. radicis-lycopersici
Didymella lycopersici
Phytophthora nicotiniae
var parasitica
Corynebacterium
michiganense
Sand
Banksia leaves
Cylindrocladium
{
Thielaviopsis basicola {
Thielaviopsis basicola
irrigation mat,
glass, wood, clay,
sand, peat
Sand
Thielaviopsis basicola
Phytophthora
cinnamomi
Erwinia amylovora
CyMV,ORSV
Plastic, wood,
metal
Banksia leaves
Pruning shears
Pruning tools
CyMV, ORSV
Pruning tools
} in vitro tests
NY 612
Efficacy
100% control after 15 min
100% control after 60 min
100% control after 15 min
100% control after 15 min
20-100% control
100% control
100% control
100%control
82-88% control
100% control
20% Physan failed to control
viruses
No control (Panacide®)
Biogram® No control
Comments
20 min exposure
3% Iobac P® Th
corrosive to meta
product was bett
hypochlorite
Drench of 50 ml
Amocid® 156 ppm (sodium
ortho phenyl phenolate)
equally or more effective
than formalin
Control, except on sand (MENNO Ter Super)
No control (Ter Spezial®)
No control
Incomplete control
Reduced transmission but
not control
Reduced transmission from
35 to 4%
Controlled at 1%
57
Drench 50 ml/po
2ml Prevent®/L
Phytotoxic at hig
Surface Disinfestation of Plant Pathogens for the Nursery Industry
Chemical
Sodium triphosphate
Pathogen
TMV
ToMV
NY 612
Situation
Mortar & pestle
Cut plant surface
Pruning shears
Efficacy
Comments
Inactivated at 5%
5 minutes
Inactivated at 3%
5 minutes
Incomplete inactivation at
15 seconds
10%
CyMV
Pruning tools
Sodium hypochlorite
Inactivated at 2%
ORSV
Pruning tools
Inactivated at 10%
phytotoxic effect
Not inctivated at 2%
no phytotoxicity
CEV
Budding knives
Inactivated at 0.26-1%/1 sec
"
ToMV
Shears
22% transmission at 0.26%
peat-vermiculite
Meloidogyne javan ica
Juveniles controlled at 4
preplant, eggs una
ppm/4 weeks
hydroponic
Gall formation stopped, 2
Treatment of infec
solutions
ppm/24 hr
juveniles, eggs un
10% /60 min No control
Sodium hypochlorite
Verticillium dahiae }
Peat debris
10%/10min Control
Didymella bryoniae }
(cont)
Pythium sp
}
1%/1 min Control
Phomopsis sclerotiodes
Peat debris
10%/60min Little control
Erwinia amylovora
Pruning shears
5% sprayed onto surface
Erwinia caotovora
Metal
with 96% control
subsp. atroseptica
Plastic
57-76% control
1% a.i./20min
Wood
first figure on clea
33-46% control
Metal
23-28% control
second on dirty su
Clavibacter
Plastic
66-95% control
michiganensis subsp.
Wood
65-100% control
sepedonicus
100-90% control
CEV = Citrus Exocortis Viroid CyMV = Cymbidium Mosaic Virus ORSV = Odontoglossum Ringspot Virus TMV = To
58