Efeitos da alimentação adicional e de cultivares de soja sobre o desenvolvimento de Diceraeus melacanthus (Dallas, 1851) (Hemiptera: Pentatomidae) e os danos fisiológicos e produtivos na cultura

Abstract

The green-belly stink bug, Diceraeus melacanthus (Dallas, 1851) (Hemiptera: Pentatomidae), has become an important pest of soybean crops, particularly in intensive agricultural systems based on soybean-maize succession and no-tillage practices, which favor its survival, persistence, and population growth throughout the year. In this context, understanding the effects of additional food resources and insect population density on its biological performance, as well as on plant responses, is essential to support more sustainable management strategies.Thus, the objective of this study was to evaluate, under greenhouse conditions, the effects of additional feeding on the development of D. melacanthus, as demonstrated in the first experiment, while the second assay aimed to assess the effects of different population densities of D. melacanthus on insect development, as well as on physiological, biochemical, vegetative, and productive parameters of soybean. A non-Bt cultivar (MONSOY® M 6404) and a Bt cultivar with tolerance technology (BLOCK® 1003IPRO) were used. In the first experiment, the effect of food supplementation associated with soybean cultivars on the biological performance of the stink bug, plant metabolism, and seed physiological quality was evaluated. The results indicated that additional feeding promoted insect biomass gain and that soybean grain residues present in the soil may facilitate insect persistence in the environment, thereby affecting seed physiological quality. The cultivar BLOCK® 1003IPRO exhibited higher antioxidant enzyme activity and a greater percentage of viable seeds, indicating physiological responses associated with tolerance to stink bug attack. In the second experiment, the effects of different population densities of D. melacanthus on insect performance and soybean yield components were analyzed. The hypothesis was that the BLOCK® cultivar, even under high infestation levels, would suffer lower yield losses (grain weight) compared to the non-Bt cultivar. An increase in the weight of fifth-instar nymphs and adults was observed, as these stages are more efficient and active in feeding and contribute to increased population density indices, regardless of the cultivar, indicating that greenhouse conditions were sufficient to meet the insect’s nutritional requirements. However, soybean yield components, such as number of pods, number of grains, and grain weight, were not significantly affected by the evaluated densities, either in the non-Bt cultivar or in BLOCK® 1003IPRO. Overall, the results demonstrate that the BLOCK® 1003IPRO cultivar did not negatively affect the development of D. melacanthus, but shows a high capacity for tolerance to stink bug attack, maintaining vegetative and productive stability even under increasing infestation levels. The findings from these two studies reinforce that the mere presence or increase in insect density does not necessarily imply economic damage, highlighting the importance of using tolerant cultivars combined with population monitoring as key tools in Integrated Pest Management (IPM) of soybean.