Selectivity of pesticides used in peach orchards on the larval stage of the predator Chrysoperla externa (Hagen)
Vargas Castilhos, RodolfoDionei Grützmacher, AndersonEdson Nava, DoriJoão Zotti, MoisésRicardo Baier Siqueira, PauloSpagnol, Daniel
The selectivity of sixteen pesticides used in peach orchards in Brazil was evaluated on larvae of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) in laboratory (25±1ºC, 70±10% RH and 14 hours photophase). The bioassays consisted on the exposure of larvae to fresh dry pesticide film applied on glass plates. Lenght of each development stage, the mortality, the fecundity and fertility of survival adults were evaluated. Pesticides were classified according to the total toxic effect in harmless ( 30%), slightly harmful (30-79%), moderately harmful (80-99%) and harmful (>99%), in conformity to International Organization for Biological Control of Noxious Animals and Plants (IOBC) recommendation. Only abamectin and deltamethrin caused significant prolongation in the post embryonic period. Fecundity and fertility of survival adults were not affected by any pesticide tested. The acaricide/insecticide abamectin, the two mineral oils, the fungicides mancozeb, dodine, azoxystrobin, captan, mancozeb + cooper oxichloride and pholpet, and the herbicide ghlyphosate were harmless; the fungicide tebuconazole was slightly harmful; the insecticide deltamethrin was moderately harmful; and the insecticides malathion, dimethoate and phosmet, and the herbicide paraquat dichloride were harmful to C. externa larvae.
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