Pentatomids (stink bugs) are major pests of soybean, Glycine max (L.) Merril. These pests reach high levels of infestation, cause severe damage to seeds by feeding, are linked to leaf retention, and are difficult to control. Host plant resistance is considered to be a valuable tool in integrated pest management and can assist in reducing the damage caused by stink bugs. This research evaluated the resistance of soybean genotypes in Brazil to the stink bug complex, the Neotropical brown stink bug, Euschistus heros (F.), redbanded stink bug, Piezodorus guildinii (Westwood), southern green stink bug, Nezara viridula (L.), green belly stink bug, Dichelops melacanthus (Dallas), and Edessa meditabunda (F.), by assessing infestation assay, yield reduction, seed damage, and leaf retention. Certain genotypes expressed different categories of resistance: least infested, low yield reduction, low levels of damage in seeds, and low levels of leaf retention. PI lines and IAC 78-2318 showed antixenotic resistance, and ‘IAC 100’ showed tolerance for the stink bug complex. This is the first study to evaluate several parameters of yield and seed quality using different soybean maturity groups under relatively high infestation by the three stink bugs species. The promising genotypes might be used in regions with a high incidence of stink bugs to manage their populations in combination with other integrated pest management practices.

Convention Center-Room W225 B Helicoverpa armigera, Spodoptera frugiperda and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) are among the main pests of corn crop in Brazil and are characterized by having the same feeding guild during the reproductive stage of the crop. The intraguild competition of these noctuides was evaluated through the survival of each specie under field conditions, on non-Bt corn. Different competition scenarios, alternating the larval stadium of development, were carried out in corn ear. The survival of H. armigera in competition with the other species was significantly low compared to the control. H. zea showed high aggressive behavior and high rate of cannibalism. Their survival was reduced when it was competing against S. frugiperda in the same size. The survival of S. frugiperda remained high in the different scenarios of competition, being reduced when it was in a lower development than H. zea and H. armigera. In general, S. frugiperda demonstrates advantage in the competition against H. zea and H. armigera on non-Bt corn.