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310 J Food Sci Technol (MayJune 2010) 47(3):310314
J Food Sci Technol (MayJune 2010) 47(3):310314 DOI: 10.1007/s13197-010-0049-6
ORIGINAL ARTICLE
Empowering the Food Professional
Insecticidal activity of the root extract of Decalepis hamiltonii against stored-product insect pests and its application in grain protection
Rajashekar Y. . Gunasekaran N. . Shivanandappa T.
Revised: 29 December 2009 / Accepted: 7 January 2010 Association of Food Scientists and Technologists (India), Mysore
Abstract Root extracts of Decalepis hamiltonii were tested for insecticidal activity against the stored products pests, Rhyzopertha domonica, Sitophilus oryzae, Stigobium pancieum, Tribolium castaneum and Callosobruchus chinensis, in residual and contact toxicity bioassays. Methanolic extract showed LC50 value of 0.14 mg/cm2 for all the test species in a lter paper residual bioassay. The extract was effective as a grain protectant for wheat and green gram. Reduction of F1 progeny was observed in treated grain stored for 34 months. The extract did not affect the germination of the treated grains. Our results indicate that methanolic extracts of D. hamiltonii has a potential to control stored product pests and could serve as a natural grain protectant.
Keywords Decalepis hamiltonii . Methanolic extract . Insecticidal activity . Insect pests . Grain protection
Introduction
Stored product insect pests reduce the quantity and quality of grain during post-harvest storage. The damage to stored grains and grain products by insects could be in the order of 510% in the temperate regions of the world and as high as 2030% in tropical countries (Shaaya et al. 1997, Nakakita 1998). The use of chemical insecticides including fumigants to prevent or control insect infestation is being practiced for grain protection. Repeated use of chemical insecticides has led to widespread development of resistance and environmental problems due to their effects on non-target organisms and concerns on human health (Subramanyam and Hagstrum 1995). In view of these problems, several chemical pesticides have been either banned or restricted for use in grain protection.
The highly successful and currently used synthetic pyrethroids were originally derived from the pyrethrum plant (Casida et al. 1975). Azadirachtin, the active principle from the Azadiraechta indica (Indian neem) plant, acts as a insect growth regulator against a number of insects (Isman et al. 1990) and also possesses antifeedant, growth inhibiting properties (Kubo and Klocke 1982, Islam...