Vol. 11, Issue 3 (2022)

Author(s):
Shyamkant Munje Munje, Sachin Pawar, DB Undirwade, US Kulkarni and AN Warghat

Abstract:
The present investigation entitled “Determination of toxicity of biological insecticides Spinosad against Callosobruchus chinensis L. pulse beetle (Chrysomelidea- Coleoptera) under laboratory conditions” was conducted in insect toxicology laboratory of Department of Agricultural Entomology, Post Graduate Institute, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, during the year of 2020-21 with objective to develop homogeneous population and from that to evaluate relative toxicity Spinosad 45% SC, against pulse beetle, C. chinensis on the basis of per cent adult mortality at 24, 48 and 72 hours after treatment (HAT). The bioassay was conducted by impregnated filter paper method with five concentrations of each four treatments including control and replicated thrice Spinosad 45% SC showed best efficiency at both LC₅₀ and LC₉₀ and it was more toxic than other insecticides at 24, 48 and 72 hours of exposure. The LC₅₀ value of Spinosad 45% SC to the adult of C. chinensis were 0.011, 0.009 and 0.007 ppm while LC₉₀ value were 0.035, 0.029 and 0.019 ppm at 24, 48, 72 hours after treatment (HAT), respectively. The log concentration Probit (Lcp) line slope (b) values of Spinosad 45% SC were 2.625, 2.638 and 3.084 at 24, 48 and 72 HAT, respectively. The insect mortality and toxicity of insecticides increase marginally at 48 hours and then at 72 hours after exposure.