A Comparative Toxicity Assessment of Insecticides against a Pollinator: The Red Brown Beetle, Epuraea motschulskyi Reitter (Coleoptera: Nitidulidae) under Laboratory Condition

Pointed gourd (Trichosanthes dioica) is a nutritionally rich cucurbit with significant dietary and therapeutic value, while its productivity largely depends on effective insect-mediated pollination due to its dioecious nature. However, the widespread use of insecticides poses a serious threat to key pollinators like Epilachna motschulskyi, necessitating evaluation of pesticide toxicity to identify safer options for sustaining pollination and crop yield. The study aims to evaluate the comparative toxicity of selected insecticides against the red brown beetle (Epilachna motschulskyi) under laboratory conditions and to identify safer insecticide options that minimize harm to this key pollinator in pointed gourd cultivation. The present investigation on toxicity of insecticides on red brown beetle, E. motschulskyi was conducted under laboratory conditions at Department of Entomology, N. M. College of Agriculture, Navsari Agricultural University, Navsari, Gujarat. The results on toxicity of insecticides revealed that significant variation in beetle mortality among treatments at all observation hours (6 to 96 hours). Cypermethrin 25 EC proved most toxic, recorded the highest (75.96%) mean mortality and reached 100 per cent mortality at 48 hours. lambda cyhalothrin 4.9 CS was the next toxic treatment with 55.96 per cent mean mortality, followed by chlorantraniliprole 18.5 SC and imidacloprid 17.8 SL. The lowest mean mortality was observed in clothianidin 50 WDG, fipronil 80 WG and emamectin benzoate 5 SG, while control showed negligible mortality. Therefore, fipronil 80 WG and clothianidin 50 WDG may be considered cooperatively safer options for conservation of beneficial red brown beetle when there is no alternate option to manage insect pollinators of pointed gourd and farmers of South Gujarat face lower fruit setting, the confirm that was causes by population reduction of beetles.