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.