EVALUATION OF SPRUCE BIOMASS EXTRACT FOR CONTROL OF GRAY
MOLD (BOTRYTIS CINEREA) ON STRAWBERRY
V. Laugale1, A. Bazenova2, J. Volkova2, S. Dane1, L. Jankevica3, M. Daugavietis4
Horticultural Research Centre, Abavas 2, Pūre, Tukuma nov., Latvia, [email protected]
2Latvian Plant Protection Research Centre, Struktoru 14a, Riga, Latvia, [email protected]
3Institute of Biology, University of Latvia, Miera iela 3, Salaspils, Latvia, [email protected]
4Latvian Forest Research Institute, Rīgas iela 111, Salaspils, Latvia, [email protected]
1Pūre
Introduction
Gray mold (caused by Botrytis cinerea Pers.) is one of the most important diseases for strawberry in Latvia. Especially high
damage can be caused in organic farms where chemical plant protection products are not allowed to use. Previous studies had
shown some antifungal effect of different components of coniferous trees. The development of new environmentally friendly
plant protection product from coniferous tree biomass against gray mold was started in 2010. Several preparative forms were
developed. The aim of these studies was to evaluate the effectiveness of spruce biomass extract for control of gray mold in
strawberry plantings .
Materials and methods
Several field trials were established in two locations in 2012 and 2013.
Trial 1
The trial was conducted in the Pūre Horticultural Research Centre (Pūre HRC) in 2012. It was established
in three-year-old strawberry plantation, cultivar ‘Senga Sengana’. Spruce biomass extract was evaluated in
two different concentrations – 1% and 2%, and with two application frequencies – one time and two times
per week from the beginning of flowering until the beginning of fruit harvesting. In total, the spraying was
done respectively four and eight times.
Trial 2
The trial was conducted in the Pūre HRC in 2013. It was established in two-year-old strawberry plantation,
cultivar ‘Senga Sengana’. Spruce biomass extract was evaluated in concentrations – 1% and 0.5%, and
with two application frequencies – one time and two times per week from the beginning of flowering until
the beginning of fruit harvesting. In total, the spraying was done respectively three and six times.
Trial 3
The trial was conducted by Latvian Plant Protection Research Centre (LPPRC) according to EPPO
guidelines PP 1/54 (3), PP 1/16 (2), PP 1/181. It was established in the farm Kekavas Darzs Ltd in 2012 in
one-year-old strawberry plantation, cultivar ‘Induka’. In this trial spruce biomass extract was applied in three
different concentrations – 1%, 2% and 4%. Extract was sprayed with the interval 7-10 days, from the
beginning of flowering until the maximum of fruit harvesting. In total, the extract was applied six times.
In all trials concentration calculations were done based on water rate 500 L ha-1.
Strawberries were grown in 20 wide matted rows with one meter distance between rows, without any
mulching and irrigation. A randomized block design with four replicates was used in all trials. The yield was
harvested two or three times per week. Total yield and average fruit weight were evaluated. Rotted fruits
were counted and weighted separately and the percentage of rotted fruits was calculated. Moreover the
fruit organoleptic evaluation was done to determine the influence of spraying with spruce biomass extract
on fruit appearance and flavour. The evaluation was done on a scale of 1-9 (1- the lowest positive
evaluation, 9- the highest positive evaluation). The spreading and development of leaf spots (%) were
evaluated after fruit harvesting period. One and two way ANOVA were used to determine the differences
among treatments. Statistical software GenStat 15th Edition was used for analysis of data from the trial in
farm Kekavas Darzs. The least significant differences between means were determined at P= 0.05.
Results
Trial 2
The highest total yield was obtained in the treatment where spruce biomass extract was applied one time per week
in concentration 1%. Treatments by spruce biomass extract significantly did not affect the yield, average fruit
weight and flavour. Lower damage by grey mold was observed in treatments where spruce biomass extract was
applied in concentration 0.5% compare to concentration 1%. The lowest percentage of rotten fruits was in the
treatment where spruce biomass extract was applied one time per week in concentration 0.5%.
9
8
7
6
5
%
4
3
2
1
0
Rotted fruits from total
numbe r
Rotted fruits from total
yield
1,0%
0,5%
1,0%
0,5%
One tim e per w eek Tw o tim es pe r w e ek Untre ated
Treatment
Fig. 2. The percentage of gray mold damaged fruits of strawberry from total number and from
total yield after different treatments by spruce biomass extract in Pūre HRC in 2013.
‘Senga Sengana’
‘Induka’
Results
Trial 1
The highest total yield was obtained in the treatment where spruce biomass extract was applied one time per week
in concentration 1%. However significant differences between treatments and untreated control were not stated. All
tested treatments by spruce biomass extract significantly did not affect the average fruit weight and fruit overall fruit
appearance and flavour. The lowest percentage of rotted fruits was observed in the treatment where spruce
biomass extract was applied in concentration 1%, two times per week (Fig. 1). However significant differences
between treatments were not stated. There were also not stated significant differences between two application
frequencies and between two concentrations used.
18
16
14
12
10
%
8
6
4
2
0
Rotted fruits from total
num ber
Rotted fruits from total yield
1%
2%
One time per w eek
1%
2%
Trial 3
In the trial in farm Kekavas Darzs the highest total yield and average fruit weight were observed in the treatment
where spruce biomass extract was applied in concentration 2%. However significant differences between
treatments and control were not stated. It was observed that application of spruce biomass extract with
concentration 4% had some influence on fruit taste and aroma – berries had specific scent and taste of conifer.
Applying of spruce biomass extract in concentrations 1 and 2% significantly reduced the development of leaf spots
(caused mostly by Mycospherella fragariae and Diplocarponn earlianum) compared to untreated control. The
lowest percentage of rotted fruits was observed in the treatment where spruce biomass extract was achieved at
treatment with the concentration 1% (Fig. 3). Statistically significant differences between treatments were not
stated.
9
8
7
6
5
%
4
3
2
1
0
Rotted fruits from total
num ber
Rotted fruits from total yield
1%
Tw o times per w eek Untreated
2%
4%
Untreated
Treatment
Treatment
Fig. 1. The percentage of gray mold damaged fruits of strawberry from total number and
from total yield after different treatments by spruce biomass extract in Pūre HRC in 2012.
Fig. 3. The percentage of gray mold damaged fruits of strawberry from total number and from
total yield after different treatments by spruce biomass extract in farm Kekavas Darzs in 2012.
CONCLUSIONS
The effectiveness of spruce biomass extract on gray mold control in the field conditions was not convincing. Better control was observed when lower concentrations of
spruce biomass extract were used. The increase of application frequency from one to two times per week did not give any significant effect on grey mold control. More
investigations on spruce biomass extract effectiveness are necessary with additional testing of lower concentrations of extract and application techniques. The influence
of extract on other disease development should be investigated.
Acknowledgements
This study has been supported by ERDF 2010/0249/2DP/2.1.1.1.0/10/APIA/VIAA/168.