Previous herbivory in soybean: effect in the chemical composition of leaves and in the development of velvetbean caterpillar and redbanded stink bug

Abstract

O objetivo desta pesquisa foi avaliar o efeito da injúria causada pela lagarta-da-soja, Anticarsiagemmatalis (Hüeb.), na composição química de folhas de soja, no desenvolvimento de A.gemmatalis (fase larval) e de ninfas do percevejo verde pequeno, Piezodorus guildinii (West.).Dois genótipos de soja, ‘Embrapa 4’ e ‘BR 37’ foram analisados quimicamente. As lagartas foramalimentadas com folhas desses genótipos e os percevejos com vagens, ambos também com injúriae sem injúria (testemunha), totalizando 4 tratamentos com 50 repetições para cada tratamento. Ainjúria foi realizada liberando-se lagartas (terceiro ínstar) (fase de florescimento). As lagartas foramretiradas quando o consumo foliar foi de aproximadamente 30%-40%. Posteriormente, as folhas eas vagens destas plantas foram utilizadas no experimento. Os resultados obtidos nesta pesquisaindicam que a composição química das folhas foi alterada e que, de modo geral, lagartas de A.gemmatalis e ninfas de P. guildinii apresentaram desenvolvimento ligeiramente superior quandoalimentados com genótipos sem injúria, sendo o genótipo ‘Embrapa 4’ mais eficiente para odesenvolvimento dos insetos.

Previous herbivory in soybean: effect in the chemical composition of leaves and inthe development of velvetbean caterpillar and redbanded stink bug

The objective of this research was to study the effect of previous herbivory in the chemicalcomposition of soybean leaves, and its influence on Anticarsia gemmatalis (Hüeb.) and Piezodorusguildinii (West.) development. Two soybean genotypes, ‘Embrapa 4’ and ‘BR 37’, were chemicallyanalyzed. The caterpillars were fed on these genotypes leaves and the bugs on string beans, bothinjured and non- injured (control), totalizing 4 treatments with 50 replications for each treatment.Herbivory was performed by releasing 3rd instar velvetbean caterpillar. The caterpillars were takenout when 30%-40% of foliar area were consumed. After that, leaves and string beans were used inthe experiment. The results obtained during this research indicate that leaves chemical compositionwas altered and that, in general, A. gemmatalis larvae and P. guildinii nymph have presentedbetter development when fed on non-injured soybean plants, being ‘Embrapa 4’ genotype themost efficient one concerning insects development.