THE RELATIONSHIP BETWEEN SPIDER MITE, Tetranychus Urticae AND ITS PREDATORY MITE, Amblyseius Fallacis IN THE PRESENCE OF CHEMICALS

The present study in directed to evaluate the relative toxicity of six chemicals of different mode of action, four Acaricides (abamectin, ethion, chlorfenapyr and Cyhalothrin), one mineral oil (Nat- 1) and one plant extract (black cumin) against the adult female mite, Tetranychus urticae and its predatory mite, Amblyseius fallacies using standardized method for bioassay. The effects of sublethal doses of these chemicals on some biological aspect of the mite and its predator were also evaluated. Results indicated that abamectin was the most toxic compound of LC50 value of 0.15 ppm, white black Cumin extract was the least one (47930. 18 ppm) to adult females of T. urticae, Also, results showed that abamectin was the most effective chemical on A. Fallacis while black cumin extract was the least toxic compound to adult females of A. Fallacis. The accumulated eggs deposited by the adult females of mite T. urticae, results suggested that cyhalothrin was the most effective compound on egg deposition followed by ethion and abamectin. Nat - 1 and black cumin extract had about the same effect on that character-Cyhalothrin was the most effective compound on egg hatchability, while Nat- 1 and black cumin extract were the least effective in egg hatchability. Cyhalothrin and abamectin caused the highest decrease in prey egg consumption by the predator, the most effective on predator egg production and caused highly decrease in egg hatchability comparable to the control treatment - Nat - 1 and black cumin extract were the least effective compounds in prey egg consumption, predator egg production and predator egg hatchability.