Seletivity of insecticides used for the control of Grapholita molesta (Busch) (Lepidoptera: Olethreutidae) in peach, to predatory Vespidae

The selectivity of the insecticides carbaryl, deltamethrin, fenitrothion, fenthion, malathion, naled, methyl parathion and trichlorfon to the predators Protonectarina sylveirae (Saussure), Polistes versicolor versicolor (Olivier) and Protopolybia exigua (Saussure) was studied in laboratory using 50 and 100% of the recommended dose for the control of Grapholita molesta (Busch) (Lepidoptera: Olethreutidae) in peach orchards. The insecticides fenitrothion, fenthion, methyl parathion, naled, and trichlorfon showed no selectivity in favour of the wasps at the full recommended dose, all of them causing 100% mortality among the predators except for trichlorfon which caused 96.9% mortality to P. sylveirae. Carbaryl and malathion were selective in favour of P. versicolor versicolor (18.6 and 6.7% mortality, respectively), and deltamethrin was selective in favour of P. versicolor versicolor (3.6% mortality) and P. exigua (11.8% mortality). P. sylveirae was more susceptible to deltamethrin than P. exigua and P. versicolor versicolor. P. versicolor versicolor was more tolerant to malathion and carbaryl than P. sylveirae and P. exigua. Deltamethrin, malathion and naled were less lethal to P. sylveirae when applied at the lower dose; while the same happened to carbaryl and malathion for P. exigua.

Insecta; Oriental fruit moth; Polistes versicolor versicolor; Protonectarina sylveirae; Protopolybia exigua

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