Effect of certain plant formulations on mortality of stored grain pest Callosobruchus chinensis Linn. (Coleopteran: Bruchidae)

Abstract

Pulses are amongst the rich sources of protein and play a very significant role in the diet of common men but unfortunately they suffer an extensive damage during the storage especially due to insect infestation, major being Callosobruchus chinensis Linn. (Coleoptera: Bruchidae).

Chemical insecticides have been vogue since least many years but have had bad consequences. The various problems associated with currently used synthetic pesticides, such as residual effects, pest resurgence, prevalent environmental and ecological hazards, insect pest resistance, and farmer economy, have led us to the use of botanicals that are environmentally friendly, biodegradable, economical, and equally effective, and also causing harm to the non-target species. The present work was therefore carried out to screen certain plant formulations against the pulse beetle Callosobruchus chinensis Linn. raised on grains of Vigna aconitifolia and to study their potency as grain protectant against the bruchid.The plants selected for the study were Azadirachta indica (Meliaceae), Prosopis juliflora (Fabaceae) and Leptadenia pyrotechnica (Apocynaceae). The plant parts taken included bark, leaves and fruit (A. indica); bark, leaves and fruits (P. juliflora) and stem (L. pyrotechnica). Different formulations were employed in the form of aqueous extract, ethanol extract, petroleum ether extract and a novel extract (Triton X-100 extract). Various dose concentrations applied were1%, 2.5%, 5% and 10%.  The aspect studied was adult mortality (expressed in per cent) of the bruchid. During the present study, the overall mean adult mortality of 100 % of the pest insect was documentedin experimental sets treated with 5 and 10% stem formulations of L. pyrotechnicaof Triton X-100 as well as ethanol extract.