Bio-efficacy of different biocontrol agents against shoot and fruit borer, Earias vittella (Fabricius) (Lepidoptera: Noctuidae) in okra

Abstract

Experiments were conducted to evaluate the efficacy of different biocontrol agents against shoot and fruit borer, Earias vittella (Fabricius) infesting okra at Biological Control farm, Anand Agricultural University, Anand (Gujarat) during two successive years, kharif, 2018 and 2019. Among the different biocontrol agents evaluated, the plots sprayed with Bacillus thuringiensis @ 5 g/litre for three times at fortnightly interval witnessed lowest larval population (0.52 larva(e)/plant) and fruit damage (7.00%-number basis, 8.09%-weight basis). The treatment comprising six releases of egg parasitoid Trichogramma chilonis @ 50,000 parasitoids/ha was found next effective treatment with lower larval population (0.67larva(e)/plant) and fruit damage (8.19%-number basis, 9.97%-weight basis). This bio-efficacy of egg parasitoid T. chilonis was statistically at par with the efficacy of treatments viz., Neem Seed Kernel Extract (NSKE) @ 5% and Beauveria bassiana@ 5 g/litre. The highest fruit yield was documented in the treatment B. thuringiensis @ 5 g/litre (111.02 q/ha, CB ratio 1:2.79) followed by the treatments T. chilonis @ 50,000 parasitoids/ha (105.10 q/ha, CB ratio 1:2.77) and NSKE @ 5% (104.64 q/ha, CB ratio 1:2.76). The significant findings of this study could be used to frame BIPM strategy for the management of shoot and fruit borer, E. vittella in okra.