SELECTIVITY OF REGISTERED AGROCHEMICALS FOR SOYBEANS AIMING IMMATURE PHASES OF TRICHOGRAMMA PRETIOSUM

Resumo

 The parasitoid Trichogramma pretiosum has great potential in controlling caterpillars, promoting a reduction in insecticide costs. However, incorrect application with mixtures with agrochemicals often results in failure and discredit of technology. The objective of this work was to evaluate, under laboratory conditions, the selectivity of pesticides reported for soybean in the immature stages (egg, larvae, pre-pupae and pupae) of parasitoids of Trichogramma pretiosum. Bioassays were conducted in the laboratory by exposing eggs parasited, using the methods proposed by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). For this, the parasitoids were obtained in the laboratory using Anagasta kuehniella eggs as a host for the multiplication of T. pretiosum. Temperature (25 ± 1 ºC), relative humidity (70 ± 10%) and photophase (14 hours) conditions were controlled both for the creation of parasitoids in climatic chambers and during bioassays in test rooms. Sixteen insecticides, six fungicides and seven herbicides registered for soybean cultivation in three immature stages of T. pretiosum were evaluated. The experimental design was completely randomized with eight replicates per treatment. Talcord 250, Nexide and Valon 384 EC are the most harmful to emergence of T. pretiosum in the larvae egg stage, while Platinum neo is more harmful in the pupal stage. Fox fungicide presented as the most harmful on the emergence of T. pretiosum in the immature stages of egg larva and pre pupa. Herbicides do not affect
the emergence of T. pretiosum when sprayed on the immature stages of egg larva, pre pupa and pupa.