Repellent efficacy of Crotalaria burhia and Anacardium occidentale against Odontotermes obesus (Isoptera: Termitidae) under laboratory conditions

摘要

Laboratory studies were carried out at bioassay lab, Institute of Pesticide Formulation Technology, Gurgaon to incur the repellent efficacy of Crotalaria burhia Buch.-Ham and Anacardium occidentale L. against Odontotermes obesus (Rambur). Aqueous root extracts of C. burhia at different concentrations, viz. 0.5%, 1%, 2.5%, 5%, 10% and 20% and powdered leaf dusts of A. occidentale at 0.5%, 1%, 2.5%, 5%, 7.5% and 10% concentrations were prepared and tested for their repellent action against O. obesus, Chlorpyrifos 20% EC was maintained as standard check. An area of preference test described by Landani et al. (1955) and Mc Donald et al. (1970) was followed and the results unveiled that root extracts of C. burhia at concentration of 10% and 20% gave a mean repellency of 66.66% and 70%, whereas 5% and 7.5% powdered leaf dust of A. occidentale gave a mean repellent efficacy of 56.66% and 60%. The lower doses of C. burhia and A. occidentale were not much effective in repelling away O. obesus. The standard check chlorpyrifos 20% EC resulted in 96.66 % and 100% repellency in both the studies. Thus higher doses of root extracts of C. burhia and powdered leaf dust of A. occidentale can be further tested for their repellent efficacy in field against O. obesus and can be included in IPM for termites, as botanicals in IPM are gaining accent as they are environmentally safe.