Bio Efficacy of Microbial Formulations of Beauveria bassiana and SlNPV against Spodoptera litura F. and Aphis craccivora Koch. in Vegetable Cowpea

Abstract

The study was conducted in the Department of Agricultural Entomology, College of Agriculture, Vellayani in 2022 with an objective to test the bio efficacy of liquid and bait formulations of Beauveria bassiana Bb 6063 and SlNPV against two most damaging pests of vegetable cowpea Spodoptera litura F. and Aphis craccivora Koch. Emulsifiable suspension (ES) formulation (comprising of Bb 6063 conidia and SlNPV @1.78 x 1010 Conidia mL-1 and 5.24 x 108 POB mL-1 respectively, in 95% sesamum oil and 5% Span- 20 + Triton-X-100 (29:71)) and bait formulation (consisting of SlNPV @4.13 x 107 POB mL-1 in, 75% wheat flour + 25% chickpea flour base matrix) developed in the current study, was evaluated under field conditions. NPV bait when applied alone and in combination with ES formulation, recorded low population of S. litura (1.33, 1.00 larvae plot-1 respectively, after two rounds of application), though inferior to chemical check Flubendiamide 39.35 SC (0 larvae plot-1). However, the leaf damage intensity score in treatments with Flubendiamide (1.53), ES formulation applied along with NPV bait (1.73) and NPV bait alone (1.57) at 10 days after two rounds of treatments were statistically on par with each other and significantly lower than rest of the treatments. Treatments with ES formulation alone and in combination with NPV bait application recorded lowest Aphis craccivora population also (0.67, 0.33 aphids plot-1) as against 9.33 aphids plot-1 in untreated control. Thus, ES formulation of Bb 6063 and SlNPV as well as SlNPV bait can be employed in the management of S. litura, wherein the former treatment is effective in controlling A. craccivora as well.