Comparative Toxicity of Some Pesticides to Tetranychus urticae Koch and two Phytoseiid Mites

Document Type : Original research articles

Authors

1 Department of Plant Protection, Faculty of Agriculture, Tishreen University, Lattakia, Syria

2 Lattakia Center for Natural Enemies Rearing, Syria

Abstract

The toxicity of nine insecticides (carbosulfan, chlorepyrifos ethyl, cypermethrin, deltamethrin, deltamethrin + dimethoate, dimethoate,diflubenzuron, and teflubenzuron), and six fungicides (carbendazim, chlorothalonil, difenoconazole, hexaconazole, kresoxim methyl, and penconazole) to two phytoseiid predatory mites: Neoseiulus fallacies German and Typhlodromus cotoneastri Wainstein was evaluated in laboratory, by spraying leaves discs. The toxicity of tested pesticide-residues that showed high toxicity to the predators in spraying method was also evaluated. Results showed that fungicides; carbendazim and kresoxim methyl, were non toxic to the tested predators, hexaconazol and chlorothalinol were slightly toxic; while difenoconazole and pencocanazole were moderately toxic. For insecticides deltamethrin was non toxic to phytoseiid mites, emamectin benzoate and diflubezuron were slightly toxic, cypermethrin and tiflubenzuron were moderately toxic, whereas carbusolfan, dimethoate, chlorepyrifos ethyl, and dimethoate + deltamethrin were highly toxic. As for the toxicity of pesticide-residues, the toxicity of cypermethrin, diflubezuron, and teflubezuron decreased to become slightly toxic when the predators were placed on the leave-discs just after the pesticides were dried out, whereas the toxicity of carbusolfan, chlorepyrifos ethyl and dimethoate did not decrease until 48 hrs passed after application. The toxicity of the insecticide to T. urticae varied, it ranged from non toxic (diflubenzuron) to highly toxic (chlorepyrifos ethyl, cypermethrin, dimethoatee, diltamethrin + dimethoatee, deltamethrin, and emamectin benzoate). The toxicity of tested fungicides to T. urticae was almost the same of their toxicity to phytoseiid mites: it ranged from non-toxic to moderately toxic.

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