Toxicity of tobacco Nicotiana tabacum Linnaeus (Solanaceae) leaf extracts to the rice weevil Sitophilus oryzae Linnaeus 1763 (Coleoptera: Curculionidae)

Abstract Background Rice is the agricultural commodity with third highest worldwide production and losses in rice storage due to insect pests may drastically affect food availability for a large number of people. One its serious tropics “rice weevil”, Sitophilus oryzae . Although few effective fumigants are available, there global concern about environmental pollution, toxicity non-target organisms, pesticide residues. Botanicals promising source pest control compounds as pool plants possessing insecticidal substances enormous have generated extraordinary interest recent years potential sources natural agents. The present study was conducted determine tobacco ( Nicotiana tabacum ) leaf extracts an alternative synthetic insecticides management weevils. crude solvent N. were analyzed phytochemical via GC-MS tested adults S. at concentrations 0.625, 1.25, 2.50, 5.00, 10.00, 20.00 mg/L by Petri dish bioassay method. Adult mortality calculated 24, 48, 72 h after exposure. Results constituent chloroform acetone revealed 13 represented benzene carboxylic acid ester, alkaloids, steroids. major found analysis nicotine, nicotinonitrile, nornicotine, nicotinic acid, neonicotine, cotinine, indole, farnesol, sclareol, 9,12-octadecadienoic squalene, palmitic 15-tetracosenoic methyl ester. Overall assessment indicates that leaves exhibited adulticidal activity against Their LD 50 values 1.62, 0.64, 0.48; 1.54, 0.83, 0.48 exposure respectively. In addition, petroleum ether extract also indicated high adult value 0.53 only h. Conclusions research has documented first report weevil using extracts, therefore on basis results study, it highly encouraging note use excellent owing action nicotine would be economically feasible alleviate problem.