New insecticides against pulse beetle, Callosobruchus chinensis in stored greengram

Laboratory studies were carried out during 2009 and 2010 to determine the efficacy of newer insecticides with novel modes of action viz., flubendiamide, emamectin benzoate, spinosad, thiodicarb, indoxacarb and lufenuron against the pulse beetle, Callosobruchus chinensis (Bruchidae, Coleoptera) in greengram. Among the insecticides evaluated, spinosad and emamectin benzoate recorded higher mortality (>90%) of adult beetles within seven days of treatment compared to the check deltamethrin (50%). Nine months after storage, spinosad, indoxacarb and emamectin benzoate were found to be highly effective against C. chinensis with low insect damage of 0.5, 0.6 and 1.0%, respectively compared to deltamethrin (23%) and untreated control (99%). The germination of greengram seed dropped to 20% in untreated control within three months of storage, where as it was maintained above 90% in all other treatments except flubendiamide (72.7%). Spinosad, indoxacarb and emamectin benzoate maintained high germination (> 90%) up to nine months of storage compared to deltamethrin (28%) and untreated control (0%). Hence, these novel insecticides have the potential to safeguard greengram seed for long term against pulse beetles.