ABSTRACT Corn, Zea mays (L.), is one of the most expressive crops in Brazil, due to its wide-ranging uses as animal feeding, biofuel production or used for human consumption. However, there is a huge gap between the actual yield and the natural yield potential of the crop, due to insects’ attack. Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae) is a key corn pest in seed producing regions, due to its attack on corn ears. Plant resistance is a valuable tool for Integrated Pest Management systems and may maintain insect populations at a level that is below an economic or damage threshold. This study aimed to evaluate the biological performance of L. zonatus in different corn genotypes, under laboratory conditions, searching for possible characterization of antibiosis/antixenosis. To achieve this goal, ten nymphs (1st instar) were transferred to polyvinylchloride (PVC) ring containing a corn ear (R6) of each genotype. Each ring corresponded to one replicate, for a total of five replicates per genotype in a completely randomized design. The parameters assessed included the duration of each instar, nymphal period, nymphal survival (%), percentage of mortality of each nymphal stage, adult longevity, and adult weight. The results demonstrate that XB 8018 Bt, 30F53, IAC Airan, XB 8030 and 30F53 YHR genotypes reduced the mean survival and caused high mortality of L. zonatus nymphs at the second instar (above 75.00%) indicating the occurrence of antibiosis/antixenosis. The higher mortality rates were observed at the second nymphal instar.

ABSTRACT Some species of pentatomids stink bugs have global economic importance, damaging various plant species during the vegetative and reproductive phases. Dichelops melacanthus (Dallas) (Hemiptera: Pentatomidae), known as the green-belly stink bug, is part of the soybean stink bug complex in Brazil and has increasing importance in crops,with potential to reduce crop yield. This polyphagous stink bug has been registered in 29 plant species belonging to 10 plant families which include cultivated and non-cultivated plants. Plant resistance is a valuable tool in integrated pest management and may reduce insect populations below economic injury level. This study characterized the resistance of 17 soybean genotypes to the green-belly stink bug. All of the materials affected the biological performance of the green-belly stink bug, but PI 227687; ‘IAC 100’; PI 171451; IAC 78-2318; D 75-10169; IAC 74-2832; ‘IAC 23’ and ‘IAC 24’ caused mortality above 80% in the second instar. ‘IAC 17’; ‘IAC 18’; PI 171451; PI 274454; ‘Conquista’ and ‘IAC 19’ decreased the longevity of adults of D. melacanthus, showing the same mechanism of resistance. PI 227687 did not allow any insects to complete the immature stage. These results are unprecedented for the species D. melacanthus and can assist breeding programs that focus on resistance to members of the stink bug complex in soybean.