EVALUATION OF ENTOMOPATHOGENIC FUNGAL ISOLATES FOR THE MANAGEMENT OF CHILLI THRIPS, Scirtothrips dorsalis Hood (THRIPIDAE: THYSANOPTERA)
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Date
2021-12
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University of Horticultural Sciences, Bagalkot. (College of Horticulture, Bagalkot).
Abstract
The present investigation on evaluation of entomopathogenic fungal isolates
for the management of chilli thrips, Scirtothrips dorsalis Hood (Thripidae:
Thysanoptera) was carried out at Department of Entomology, College of Horticulture,
University of Horticultural Sciences, Bagalkote, India during 2020-21. In the first part
of the study, the bioefficacy of eight local isolates of entomopathogenic fungi (EPF)
against chilli thrips was evaluated under semi-field conditions. The results indicated
that, among the different isolates Beauveria bassiana (BbM) was significantly
superior in reducing thrips population and LCI due to thrips, followed by
Lecanicillium lecanii (LlA2), L. lecanii (LlM) and Fusarium semitectum (FsB3).
Therefore, these four isolates were selected for the field evaluation in the second part
of the study. Under field conditions, all the EPF’s tested were found to be effective in
suppressing the thrips population as judged from the mean thrips population, LCI due
to thrips and per cent reduction over untreated control. Significantly lowest thrips
population, LCI for thrips and highest reduction over control was noticed in the plots
treated with the local isolate BbM @ 2 g/l (2.03 thrips/3 leaves, 0.80 and 52.12 %,
respectively) followed by LlA2 @ 2 g/l (2.22 thrips/3 leaves, 0.80 and 48.69 %,
respectively). Further, highest green chilli yield and B:C ratio were also recorded in
the plots treated with BbM (18.12 t/ha and 1.97, respectively) followed by LlA2
(18.00 t/ha and 1.95, respectively) and commercial strain of B. bassiana BbC (16.67
t/ha and 1.81, respectively) which were statistically on par with the botanical
azadirachtin 10000 ppm (17.89 t/ha and 1.93, respectively). Relatively higher
thermotolerance and the better host specific interactions might have attributed to
comparatively superior performance of these local isolates than the other EPF’s.
Therefore, local isolates of EPF’s can be considered as promissive alternative to
chemical insecticides and could be effectively incorporated in the ecofriendly
management of chilli thrips.