Selectivity of pesticides used in peach orchards to eggs and pupae of the predators Chrysoperla externa and Coleomegilla quadrifasciata

Abstract

This study aimed to assess, under laboratory conditions, the selectivity of nine pesticides used in peach to the egg and pupal stages of the predators Chrysoperla externa and Coleomegilla quadrifasciata. Tests consisted of the direct application of pesticides on eggs and pupae of predators and assessment of sublethal effects on fertility and fecundity of emerged adults. For eggs, the pesticides were classified according to the effects on the reduction of the percentage of larval hatching, while for pupae they were classified as a function of the total effect, according to the toxicity scale proposed by the International Organization for Biological and Integrated Control (IOBC). All the pesticides (used dose) were harmless (class 1) to eggs of C. externa, but abamectin (80) and copper + calcium (1%) were considered slightly harmful (class 2) to pupae. In bioassays with C. quadrifasciata, abamectin (80), deltamethrin (40), and malathion (150) were classified as slightly harmful (class 2), while fenitrothion (100) was moderately harmful (class 3) to predator eggs; in the pupal stage, abamectin (80), fenitrothion (100), and malathion (150) were considered harmful (class 4). Azadirachtin (1%), chlorantraniliprole (14), deltamethrin (40), copper + calcium (25% + 10%), and sulfur + calcium (3.5 Ba) were harmless (class 1) to eggs and pupae of C. externa and C. quadrifasciata and thus should be prioritized in sprayings for pest control in the IPM of peach.