Seletividade de Agroquímicos Utilizados na Produção Integrada de Maçã aos Parasitóides Trichogramma pretiosum Riley e Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae)

Abstract

Parasitoids of genus Trichogramma represent an alternative to control tortricids in apple orchards; however, it is necessary to use selective pesticides for managing this crop. The side-effects of pesticides used in Integrated Production of Apples, were evaluated to parasitoid Trichogramma pretiosum Riley and Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) under laboratory conditions, by following protocols of IOBC/WPRS. Bioassays were carried with: a) adults by exposing to fresh pesticides residues, applied on glass plates; b) immature stages, with applications of pesticides on eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae), with the parasitoid in the egg-larvae, pre-pupae and pupae stages. The reduction in the parasitization (adults) and reduction on adults emergence (immatures), in relation the control were used to classified the pesticides in harmless (<30%), slightly harmful (30-79%), moderately harmful (80-99%) and harmful (>99%). Out of 60 pesticides tested in bioassays with adults of T. pretiosum, 60% were harmless, 10% slightly harmful, 16.67% moderately harmful and 13.33% harmful. In bioassays with immatures, out of 19 pesticides evaluated, 73.68% were harmless for all immatures stages and the others were slightly harmful in at least one stage. For T. atopovirilia, of the 40 pesticides evaluated with adults, 45% were harmless, 15% slightly harmful, 12.5% moderately harmful and 27.5% harmful; in bioassays with immatures of the 17 pesticides tested 58.82% were harmless for the three stages, while 41.18% were slightly harmful, moderately harmful and harmful. T. atopovirilia was more sensitive than T. pretiosum to evaluated pesticides in the tests with either adults or immatures.