Abstract:
Phytopthogen are simply an organism parasitic on a plant host resulting the
serious problems regarding crop losses in agriculture sector. To facing such a
threat, it is very wise to use Biological Control Agents (BCA’s) like
Trichoderma, a soil-borne filamentous fungi that are capable of parasitizing
several plant pathogenic fungi. It is a potential fungal BCA’s against a range of
plant pest and pathogens. Unfortunately, popularization of bio-pesticides is very
slow as compared to chemicals and only 0.035% bio-pesticides are available in
pesticides market share of Nepal as of 2011/12. Trichoderma harzanium and
Trichoderma viride have curved a niche for themselves in Nepal as important
BCA’s for management of various diseases. In this study, Trichoderma and
phytopathogens were isolated from soil samples and diseased plant parts using
soil dilution plating methods and tissue culture techniques respectively.
Thereafter, antagonistics properties of eight T-isolates coded as Tar, T22, I2, I3,
TV, T-gel, TH3 and Dar were evaluated against fourteen phytopathogenic fungi
(Acremonium spp., Alternaria brassisicola, Exsirohilum turcicum, Fusarium
spp., Macrophomina phaseolina, Penicillium spp., Rhizoctonia solani,
Sclerotium rolfsii) tested in vitro study using dual culture techniques volatile and
non-volatile compounds methods whereas in vivo study includes germination
percentage and percentage increased or decreased of diseases severity over
control. In dual culture techniques and non-volatile compound effects, it is
found that T-isolates has maximum growth inhibition of R. solani (as much as
100% overgrowth) whereas M. phaseolina has lowest effect on it. Generally
volatile organic compounds of T-isolates shows moderate and similar effect on
phytopathogen except M. phaseolina which has almost no effect on them. Study
conducted on vivo trail gives satisfactory results to proof T- isolates as a very
potent BCA’s. Overall results analysis shows Trichoderma isolates Tar and I2
are very potent BCA’s and could be recommended for mass production of
Trichoderma based biopesticides from them. Present study concludes the uses
of Trichoderma and assessment of their suitability as bio-pesticides for control
of selective fungal phytopathogen.
Description:
A Dissertation
Submitted to the Department of Microbiology,
Central Campus of Technology, Tribhuvan University, Dharan,
Nepal, in Partial Fulfillment of the Requirements for the Award of
Degree of Master of Science in Microbiology
(Agriculture)