SIDE-EFFECTS OF THREE ACARICIDES ON THE PREDATORY MITE, PHYTOSEIULUS PERSIMILIS ATHIAS-HENRIOT (ACARI: PHYTOSEIIDAE) UNDER LABORATORY CONDITIONSAbstract : The predatory mite Phytoseiulus persimilis Athias-Henriot is an economically important species in integrated mite pest management and biological control of spider mites in many countries throughout the world. For optimal biological mite management, it is important to know if acaricides have adverse undesirable effects on the predatory mites. The toxic effects of hexythiazox (Nisorun®, EC 10%), fenpyroximate (Ortus®, SC 5%) and abamectin (Vertimec®, EC 1.8%) on P. persimilis were evaluated. The acaricides were applied on detached bean leaves using a Potter Tower spray which deposited 2 mg spray solution per cm2. Percent predator mortality was evaluated from the protonymph up to the adult stage including first five days of the oviposition period. The results showed that the total effect values of all concentrations of hexythiazox were below the lower threshold thus it could be considered a harmless acaricide to this predatory mite. In contrast, the total effect of all concentrations of fenpyroximate, and field, as well as, one half the field concentration of abamectin were found toxic to predatory mite and above upper threshold.