Cotoxicity of Inert Minerals and Spinosad Against Pulse Beetle in Blackgram

Cotoxicity of inert minerals and spinosad against pulse beetle Callosobruchus maculatus (Fabricius) in blackgram was evaluated in the laboratory of Department of Entomology, Agricultural College, Bapatla during 2020-21. Inert minerals like diatomaceous earth, china clay, paddy husk ash, and cow dung ash were used. Spinosad was mixed with these treatments in 1:1, 1:5, 1:10, 1:20, 1:50, and 1:100 ratios. The mixed formulations were used for the bioassay with one-day-old adult beetles by mixing with seed. Data were recorded at 1,2,3, 5, and 7 days after the release of the test insect. The data on co-toxicity co-efficient values of inert minerals by mixing with seed method against adult C. maculatus revealed that the highest co-toxicity co-efficient value was observed for diatomaceous earth (150). The lowest co-toxicity co-efficient value was observed for cow dung ash (87.30) at a combined LD50 value of 189 mg per 50 g at 7 DAT.