EFFECTS OF PURE AND FORMULATED AZADIRACHTIN, A NEEM-BASED BIOPESTICIDE, ON THE PHYTOPHAGOUS SPIDER-MITE, TETRANYCHUS-URTICAE KOCH

Pure azadirachtin-A (AZ-A) and four neem-based formulations (RH, MO, PT and AT) containing the insecticide isomer were tested for their repellency, toxicity and oviposition deterrence against the phytaphagous two-spotted spider mite (Tetranychus urticae Koch). Mites were placed on treated and untreated aspen (Populus tremuloides Michx.) leaf discs and their fecundity, feeding rate and mortality were assessed. Results indicated that the effects of AZ-A on T. urticae varied with formulation type and AZ-A concentration. Significant reductions in feeding and oviposition, which correlated with AZ-A concentrations, were recorded concomitantly with a significant increase in repellency. Leaf discs treated with increasing concentrations of the formulations showed increased mortality of T. urticae, reduction in the total number of eggs laid, reduced % of eggs hatched and reduced survival of emerged mites. The deterrent and biological effects decreased in the order AT>PT>MO>RH>AZ-A.