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NURSERY DISE.ASES OF BLACK PEPP~.
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(Pipel~nigl"um L.) IN KERALA WITH SPECIAL
REFERENCE TO THE MANAGEMENT OF
Phytophthora capsici Leonhin, emend. Alizadeb and Tsao
By
K. P. MAMMOOTTY
THESIS
Submitted in partial fulfilment of the
requirement for the degree of
JoctorofPhilosophy
in Rgritulturt
Faculty of Agriculture
Kerala Agricultural University
Department of Plant Pathology
COLLEGE OF HORTICULTURE
VELLANIKKARA9 THRISSUR
KERALA, INDIA
2003
- 680656
CERTIFICATE
Certified that this thesis, entitled "Nursery diseases of black pepper (Piper
nigrum L.) in Kerala with special reference to the management of Phytophthora
capsid Leonian, emend. Alizadeh and Tsao" is a record of research work done
independentlyby Mr.K.P. Mammootty under my guidance and supervision and that it
has not previously formed the basis for the award of any degree, fellowship or
associateshipto him.
Vellanikkara
~M!
Dr.
hy Abraham
Chairman of A v'sory Committee
Associate ofessor and Head
Departme of Plant Pathology
College of Horticulture
Vellanikkara
ABSTRACT
Nursery diseases are the major limiting factor' in the production of quality
planting materials of black pepper. Investigations were carried out to study the various
diseases occurring in black pepper nurseries of northern districts of Kerala, the effect
of nursery practices on the incidence of diseases and to evolve an integrated
management strategy against Phytophthora rot in black pepper nursery.
Four nursery diseases viz., fhytophthora
rot, Colletotrichum rot,
Rhizoctonia rot and Sclerotium rot were recorded from different nurseries surveyed.
The pathogens causing the diseases were isolated and identified as Phytophthora
capsid Leonian emend A. Alizadeh and P.H.Tsao, Colletotrichum gloeosporioides
(Penz.) Penz. Sacc., Rhizoctonia solani KUhnand Sclerotium rolfsii Sacco
Symptomatology of these diseases were studied. The pathogen P. capsid
produced symptoms on all parts of the plant, while C. gloeosporioides infected mainly
on leaves. R. solani and S. rolfsii infected both leaves and collar regions. The infected
plants produced typical symptoms depending upon the pathogen and plant parts
affected.
Incidence of nursery diseases varied with locations and nursery seasons.
Among the nursery diseases noticed during the survey, Phytophthora rot was the most
predominant one. Incidence of other three diseases was comparatively less than that of
Phytophthora rot.
Various nursery practices followed for raising pepper nurseries viz.,
nursery structures, potting mixture, place of collection of planting materials, variety /
cultivar planted, processing of runner vines, treatment of potting mixture, time of
planting, frequency of irrigation mid application of fungicides had an effect on the
incidence of nursery diseases especially Phytophthora rot. However, cuttings raised
under high density polyethylene sheet did not show any incidence of diseases.
Screening for host resistance indicated tolerant and moderately susceptible
reactions of Kalluvally-II and Panniyur-S respectively against nursery diseases. The
biochemicalparameters of these genotypes, which impart this type of reactions, were
studiedin comparison with susceptible Panniytu-l.
Total phenols, OD phenol and total free amino acid contents and
peroxidase, catalase and esterase activities were more in tolerant Kalluvally-II, while
total carbohydrates, starch and acid phosphatase activity were maximum in susceptible
Panniyur-l. Reducinp sugar content was high in moderately susceptible Panniyur-S.
Quantitative estimation of rhizosphere microflora from different pepper
nurseries yielded bacteria, actinomycetes and fungi. Fungal antagonists exerted more
antagonistic activity against P. capsici both under in vitro and in vivo conditions.
Among these two isolates FI4 and F48 were selected based on their better antagonistic
efficiency against P. capsici and they were identified as Trichoderma harzianum Rifai
and Trichoderma viride Pers. ex S.F. Gray aggr. The established antagonists
T harzianum and T viride also exerted good antagonistic efficiency against
P. capsici.
The native and established antagonists were compatible with Akomin-40
and Ridomil MZ, while Bordeaux mixture and Fytolan were not compatible with any
of the four fungal antagonists.
Better growth and minimum disease incidence in pepper cuttings were
recorded when nurseries were raised during February-March.
Pepper cuttings raised in solarized potting mixture for 30 days showed
more sprouting, better plant growth and less incidence of disease.
Integrated management of Phytophthora rot in blac~ pepper nursery was
carried out using tolerant Kalluvally-II, moderately susceptible Panniyur-S and
susceptible Panniyur-l. In all the three black pepper genotypes, all the treatments had
a significant effect in reducing the incidence of Phytophthora rot when comparedwith
control. The minimum disease incidence in Panniyur-l and Panniyur-S was recorded
in cuttings in treatment T14(Solarization of potting mixture for 30 days + T. viride +
Akomin-40), while in Kalluvally-II it was Tzo(Solarization of potting mixture for 30
days + T. harzianum- F14 + Akomin-40). In general, solarization of potting mixture,
application of Trichoderma spp. and fungicides like Akomin 40 and / or Ridomil MZ
can be used for managing the incidence of Phytophthora rot in black pepper nursery.