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Selectivity of insecticides to Doru luteipes (Scudder, 1876) (Dermaptera: Forficulidae) and Cotesia sp. (Hymenoptera: Braconidae) natural enemies of Ascia monuste orseis (Godart, 1818) (Lepdoptera: Pieridae)

This work aimed to study the selectivity of the insecticides carbaryl, deltamethrin, methyl parathion, permethrin and trichlorfon in favor of the predator Doru luteipes (Scudder) (Dermaptera: Forficulidae) and of the parasitoid Cotesia sp. (Hymenoptera; Braconidae) in relation to the control of the kale leafworm Ascia monuste orseis (Godart) (Lepidoptera: Pieridae). LC90 were determined for A. monuste orseis, and these were used as discriminatory doses to evaluate the degree of selectivity of the insecticides. Deltamethrin and permethrin were highly selective in favor of D. luteipes. Deltamethrin was intermediate selectivity in favor of Cotesia sp., while permethrin was not selective in favor of this parasitoid. Trichlorfon was highly selective in favor of fourth instar nymphs and adults of D. luteipes, and it was intermediate selectivity in favor of Cotesia sp. and first instar nymphs of the predator. Carbaryl was intermediate selectivity in favor of Cotesia sp., but it did not show selectivity in favor of D. luteipes. Methyl parathion did not show selectivity in favor of D. luteipes and Cotesia sp. Adults of D. luteipes were less sensitive to deltamethrin, permethrin and trichlorfon than adults of Cotesia sp. and the inverse happened with carbaryl. Both natural enemies presented high sensibility to methyl parathion. Fourth instar nymphs of and adults of D. luteipes were more sensitive to methyl parathion and trichlorfon than first instar nymphs. Both nymphs and adults of D. luteipes presented similar sensibility to the carbaryl, deltamethrin and permethrin.

Brassica; Braconidae; integrated pest management; natural enemies; kale leafworm


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