Inoculative releases of Telenomus podisi Ashmead (Hymenoptera: Scelionidae) for management of the stink bug complex in soybean crops

Abstract

The complex of phytophagous stink bugs is responsible for considerable reductions in the yield potential of soybean crops. Insecticides are usually used for the management of these pests; however, the egg parasitoid Telenomus podisi Ashmead (Hymenoptera: Scelionidae) has become a promising alternative due to its mass production and commercialization in Brazil. This study evaluated the efficacy of inoculative releases of T. podisi prior to the crop critical period of stink bug attack. The experiments were carried out in the field during the 2019/20 and 2020/21 crop years, using a drone for parasitoid releases. The combined analysis of both crop years showed the potential replacement of chemical control with biological control with T. podisi in the initial applications. This change did not significantly affect crop yield, thousand-seed weight (TSW), and seed physiological quality assessed in germination and tetrazolium tests. In addition, the treatment with the first application performed with the parasitoid release, followed by two applications of synthetic insecticides (applied fortnightly), showed no significant differences in the number of stink bugs captured in a vertical beating cloth when compared to the farmer’s pattern (three insecticide applications). Moreover, abundance of generalist predators was higher in the control (without application) and in the treatment constituted by two T. podisi releases. Thus, inoculative releases of T. podisi prior to the critical crop period constitute a promising management alternative for the stink bug complex in soybean crops, contributing to the stability and sustainability of the production system.