Selectivity of Annona (Annonaceae) Extract On Egg Parasitoid Trissolcus Urichi (Hymenoptera: Platygastridae)

The effect of the Annona crassiflora (Annonaceae) extract was evaluated on the egg parasitoid Trissolcus urichi (Hymenoptera: Platygastridae), natural enemy of Euschistus heros (Heteroptera: Pentatomidae), major pest of soybean in Brazil. For this two bioassays were conducted with extract concentrations 0.5%, 1.0%, 2.0% and 4.0% and controls (distilled water and DMSO). In the first bioassay, unparasitized eggs of E. heros were treated with the extract of A. crassiflora and offered to T. urichi females. In the second bioassay, parasitized eggs were treated in three stages in order to achieve different development stages of T. urichi (egg, larvae and pupae). The variables evaluated were the number of eggs parasitized and parasitoids emerged. The percentage of parasitism was calculated and classified according to IOBC. The extract of A. crassiflora reduced parasitism in concentrations higher than 0.5% when applied on unparasitized eggs and, when applied on parasitized eggs, it did not affect the developmental stages of the parasitoid, indicating the selectivity of the extract on the development of the parasitoid. This is an important result to be considered in a field test, useful as for decisions on the moment of application and the release of the wasps.