Bioefficacy of plant extracts on Callosobruchus chinensis infesting stored pea

Bioefficacy of acetone extracts of leaves of worm's wood (Artemisia roxburghii L. and A. annua L.), mint (Mentha longifolia L. and M. spicata L.) marigold (Tagetus erecta L.) and seed kernels of dharek (Melia azedarach L.) was studied against the pulse beetle, Callosobruchus chinensis L. infesting pea (Pisum sativum L.) seeds in storage. The extracts were evaluated for their oviposition deterrent activity, direct toxicity, F₁ adult emergence, weight loss and seed damage at four different concentrations (1%, 2% 4% and 6%). Maximum oviposition deterrent activity (94.9%) and mortality (100% at 7 day after treatment) of the beetle was observed in M. azedarach seed kernel extract at 6% and it proved to be the most effective among the six plant extracts tested against the pulse beetle in terms of the pea seed damage (1.0%), weight loss (0.4%) and progeny development (nil) from treated grains tested up to six months of storage. It was followed by T. erecta, A. annua, M. longifolia, M. spicata, while the least effective was A. roxburghii. All these extracts did not affect the viability of seeds even after six months of treatment.