Side-effects of three pesticides on the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae).
Side-effects of three commonly used pesticides in Iran were evaluated on an introduced strain of the predatory mite. Phytoseiulus persimilis Athias-Henriot, reared for about 10 years without exposure to any pesticides. Application of pesticides was carried out either to detached bean leaves using a Potter tower at 1 mg wet deposit per cm2 or by a hand sprayer on bean plants until run off. According to an EPPO decision making scheme, pirimiphos-methyl was found to be harmful (E=90.8%) and heptenophos harmless (E=-3.7%) to the predatory mite in the residual initial toxicity tests. For determination of the hazard class of malathion a field test was found to be necessary (E=59.8%). Categories of 1, 2, 3 were determined for heptenophos, malathion and primiphos-methyl, respectively, using IOBC classification. Despite being harmful, it is possible to use pirimiphos-methyl 10 days before release of P. persimilis. Investigation of the contribution of both lethal and sub-lethal effects to total impact indicated the dominance of lethality in the case of pirimiphos-methyl, while malathion acted by both mechanisms. Heptenophos did not have negative effects on fecundity of P. persimilis but rather caused a higher rate of fecundity in comparison with the control. The mortality found in the heptenophos test was not significantly different from the control.
Kavousi
A
A
Plant Protection Department, College of Agriculture, University of Tehran, Karaj 31584, Iran.
Talebi
K
K
D000704:Analysis of Variance; D000818:Animals; D005298:Fertility / Q000187:drug effects / Q000502:physiology; D008294:Malathion; D008925:Mites / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology*; D009943:Organophosphorus Compounds; D009946:Organothiophosphorus Compounds; D010575:Pesticides / Q000633:toxicity*; D027805:Phaseolus / Q000469:parasitology; D018515:Plant Leaves / Q000469:parasitology; D011235:Predatory Behavior / Q000502:physiology*
D009943:Organophosphorus Compounds; D009946:Organothiophosphorus Compounds; D010575:Pesticides; C014153:pirimiphos methyl; C014022:heptenophos; D008294:Malathion