Efficacy of some botanicals and antagonists in the management of damping-off of Chilli (Capsicum annuum L.) caused by Pythium aphanidermatum (Edson) Fitzp
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Date
2018
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DEPARTMENT OF BIOLOGICAL SCIENCES FACULTY OF SCIENCE SAM HIGGINBOTTOM UNIVERSITY OF AGRICULTURE, TECHNOLOGY & SCIENCES (FORMERLY ALLAHABAD AGRICULTURAL INSTITUTE) ALLAHABAD-211007 UTTAR PRADESH
Abstract
The experiment was carried out to screen the botanicals and biocontrol agent to
study their effect on Pythium aphanidermatum. Also to check the effect of potential
botanicals and biocontrol agents on damping-off (Pre and Post-emergence) under pot
condition and growth parameter, yield and cost benefit ratio under field conditions.About
60% losses at seedling stage in both nursery and field level have been reported due to
damping off disease in chilli caused by Pythium aphanidermatum. It is a soil-borne plant
pathogen causing seed rot and damping-off diseases in many vegetables. The efficacy of
23 fungal (Trichoderma spp.), 8 bacterial (Pseudomonas and Bacillus spp.) and 20 leaf
extracts were tested for their ability to inhibit the growth of P. aphanidermatum, the causal
agent of chilli damping-off. In vitro studies revealed that Trichoderma harzianum, Bacillus
subtilis and Lantana camara showed the maximum inhibition of mycelial growth (98.19,
80.03 and 98.88%) followed by Trichoderma asperellum, Pseudomonas fluorescens and
Eucalyptus globulus (88.89, 76.28 and 94.08%) of P. aphanidermatum respectively.
Effective treatments (5 biocontrol agents viz., T. harzianum, T. asperellum, T. hamatum, B.
Subtilis and P. fluorescens and 4 botanicals viz., L. camara, E. globulus, C. roseus and L.
inermis) were selected for pot culture evaluation against pre-emergence and post-emergence
of chilli. Pooled data of two year of pot trial revealed that the maximum effective treatments
were as seed treatment with T. harzianum (2 × 108 CFU ml-1), P. fluorescens (1 × 109 CFU
ml-1) and L. camara (20%). These treatments gave maximum protection against pre and
post-emergence damping-off and were comparable to the fungicide Ridomil. The possible
reasons might have involved in the reduction of damping-off incidence and increased the
plant growth and yield of chilli, were antifungal compounds present in biocontrol agents and
botanicals were confirmed through GC-MS. Twenty one major compounds were found in
ethyl acetate extract of T. harzianum, in which 6 pentyl-α-Pyrone Heneicosane and
Harzianic acid are known to have antifungal effect. In methanolic extract of L. camara, β-
Caryophyllene, α-Humulene and Caryophyllene oxide were found. Based on above
findings, the biocontrol agents and botanicals found safe and effective and may be used as
an efficient and eco-safe alternative of chemical fungicide for the management of dampingoff
of chilli and for obtaining enhance shoot length, root length, higher yield and cost
benefit ratio.
Description
Ph. d. thesis
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