LABORATORY AND FIELD EVALUATION OF A NEEM INSECTICIDE AGAINST ARCHIPS ROSANUS L. (LEPIDOPTERA: TORTRICIDAE)

Abstract

AbstractA commercial formulation of neem seed extract, Margosan-O, containing 0.3% AI azadirachtin, was tested under laboratory and field conditions against the European leafroller, Archips rosanus L. In laboratory tests, a 1% aqueous solution of neem insecticide produced 100% larval mortality within 48 h of treatment. At lower concentrations of 0.1 and 0.01%, 48-h mortality rates were reduced. Prolonged deleterious effects of sublethal treatments of neem were observed even at the lowest concentration (0.001%) tested. Mortality in the 0.1 and 0.01% treatments group reached 100% within 32–39 days after treatment. Field data showed that 3 weeks after application, 1% Margosan-O was as effective as the organophosphate insecticide diazinon and significantly more effective than the microbial insecticide Dipel (Bacillus thuringiensis). Larvae exposed to higher concentrations of neem died within 48 h after feeding on treated foliage. At lower rates, feeding deterrence (including cessation of feeding) and growth regulatory effects (e.g. difficulty in molting, abnormal larval growth, and formation of malformed pupae and adults) were recorded.