Seed-sucking insects are economically important pests affecting soybean in Brazil. The objective of this study was to evaluate the effect of chemical inducers on insect resistance in soybean on the neotropical brown stink bug, Euschistus heros (F.) (Hemiptera: Pentatomidae) using varying levels of inherent resistance in soybean. Seedpods from of the soybean varieties 'IAC 100' and 'IAC 17' (antibiosis resistant and non-preference resistant varieties, respectively), 'Conquista' (moderately resistant), and 'Jataí' (susceptible) that had been treated with one of several inducers, or untreated, were evaluated in choice-and no-choice tests. In addition to analyses of feeding preference, effects of the treatments on the development of E. heros were also studied. The nonpreference and antibiosis resistances of varieties 'IAC 17' and 'IAC 100' were observed when plants of these varieties treated with resistance inducers were fed to E. heros. Potassium silicate, calcium magnesium silicate, and acibenzolar-S-methyl (ASM) inducers were found to have a synergistic effect on the resistance of 'IAC 17' and 'IAC 100' to E. heros. These soybean varieties can be directly used by farmers or associated with silicon application to prevent damage caused by E. heros.

Spodoptera eridania (Cramer) is a growing pest in crops that has been causing damage due to defoliation and lesion in reproductive structures, which requires studies of development in different types of hosts. The objective of this study was to evaluate the development of S. eridania in different species of host plants. The larvae were reared in laboratory in cotton plants of the Delta Opal cultivar. The caterpillars of newly hatched larvae were placed in Petri dishes and fed on these plants: black velvet bean (Stizolobium aterrimum), guandu bean (Cajanus cajan), jack bean (Canavalia ensiformes), forage radish (Raphanus sativus), sunnhep (Crotalaria juncea) and millet (Pennisetum americanum). The following parameters were evaluated: attractiveness and consumption in a multiple choice test; viability; larval and pupal period and weight; sex ratio; adult longevity; and total duration of the development cycle. The jack bean and forage radish plants showed greater attractiveness and were the most consumed ones by S. eridania caterpillars. The larval period was shorter among the larvae fed on black velvet beans in comparison to guandu beans, jack beans, forage radish and C. juncea. Larvae fed on forage radish and C. juncea leaves had the heaviest pupal weight. The best progress of caterpillars was obtained in the following hosts: guandu bean, forage radish and C. juncea. The millet had a negative influence on the biological parameters of caterpillars, thus not proving to be a viable host, since larval mortality was of 100%.KEYWORDS: black caterpillar; nutritional ecology; alternative host. RESUMO:Spodoptera eridania (Cramer) é uma praga em expansão nas culturas, que vem causando prejuízos pela desfolha e pela lesão nas estruturas reprodutivas, o que leva à necessidade de estudos de desenvolvimento em diferentes tipos de hospedeiros. O objetivo do trabalho foi estudar o desenvolvimento de S. eridania em diferentes espécies de plantas hospedeiras. As lagartas foram criadas em laboratório em plantas de algodoeiro do cultivar Delta Opal. As lagartas recém-eclodidas foram individualizadas em placas de Petri e alimentadas com as plantas: mucuna-preta (Stizolobium aterrimum), feijão--guandu (Cajanus cajan), feijão-de-porco (Canavalia ensiformes), nabo-forrageiro (Raphanus sativus), Crotalaria juncea e milheto (Pennisetum americanum). Os parâmetros avaliados foram: atratividade e consumo em teste com chance de escolha; viabilidade; período e peso larval e pupal; razão sexual; longevidade de adultos; e duração total do ciclo de desenvolvimento. As plantas de feijão-de-porco e nabo--forrageiro apresentaram maior atratividade e foram as mais consumidas pelas lagartas de S. eridania. O período larval foi menor nas lagartas alimentadas com mucuna-preta do que com feijão-guandu, feijão-de-porco, nabo-forrageiro e C. juncea. Lagartas alimentadas com folhas de nabo-forrageiro e C. juncea tiveram os maiores peso de pupa. Os melhores desenvolvimentos das lagartas foram obtidos nos hospedeiros feijão-guandu, nabo-forrageiro e...

Seed coat tear is frequently occurs in some soybean cultivars. The impact of seed coat tear on seed physiology and sanitation is uncertain. Our objective was to analyze the physiological and pathological effect of tear on soybean (Glycine max) seed coat. The cultivars NS-8338-IPRO (with high incidence of tear) and NS-6906-IPRO (with low incidence of tear) were used. A tetrazolium test was used to assess the physiological quality of the seed coat before and after storage. The sanitary quality was assessed through the "Blotter Test". For each storage period, we evaluated seeds with 0% coat tear, up to 10%, and above 10%. The experiment was performed in a completely randomized design using the methodologies proposed by RAS. The coat tear on soybean seed positively contributed to the moisture damage affecting the inner part of the seed. Incidences of Fusarium sp. and Aspergillus sp. were frequently observed in torn seeds and in seeds without tear (around 9-10%) but did not interfere with seed quality. The appearance of coat tear on soybean seed is increased by moisture damage and do not serve as a gateway for the fungi to cause damage during seed emergence.

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