RESUMEN
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.
Asunto(s)
Glycine max/genética , Herbivoria , Heterópteros , Animales , GenotipoRESUMEN
Bemisia tabaci biótipo B é um dos principais insetos-praga na cultura da abobrinha (Cucurbita pepo L.). O manejo dessa mosca-branca tornou-se grande desafio aos agricultores, uma vez que esta apresenta rápida capacidade de desenvolver resistência a diferentes classes de inseticidas. Como alternativa vem sendo investigado o uso de extratos vegetais com atividades inseticida e/ou insetistática, os quais têm revelado resultados promissores no combate a inseto. O presente trabalho teve por objetivo avaliar os possíveis efeitos de sete extratos provenientes de cinco espécies vegetais, Ruta graveolens L. (folhas), Azadirachta indica A. Juss. (folhas + ramos), Trichilia pallida Swartz (ramos), T. pallida (folhas), A. indica (amêndoas), Chenopodium ambrosioides L. (inflorescências + ramos+ folhas) e Mentha pulegium L. (folhas), sobre Bemisia tabaci biótipo B em abobrinha, por meio de testes de repelência e deterrência para oviposição. Em teste com chance de escolha, avaliou-se a atratividade e determinou-se o índice de repelência após 6, 24 e 48 horas da aplicação dos extratos. A oviposição foi verificada após a terceira contagem do número de adultos. O extrato à base de folhas de M. pulegium mostrou repelência e deterrência à oviposição de B. tabaci biótipo B, podendo ser recomendado como alternativa para o manejo do inseto.
Bemisia tabaci biotype B is one of the main pests in squash (Cucurbita pepo L.). The management of this whitefly has become a major challenge to growers, since they have the ability to quickly develop resistance to different classes of insecticides. Alternatively, the use of plant extracts with insecticide and/or insectistatic activities has been investigated, showing promising results for the whitefly control. The present study evaluated the possible effects of seven extracts from five plant species, Ruta graveolens L. (leaves), Azadirachta indica A. Juss. (leaves + branches), Trichilia pallida Swartz (branches), T. pallida (leaves), A. indica (almonds), Chenopodium ambrosioides L. (inflorescence + leaves + branches) and Mentha pulegium L. (leaves) on Bemisia tabaci biotype B in squash, by assays of repellence and oviposition deterrence. In free choice tests, the attractiveness and determination of the rate of repellence (with 6, 24 and 48 hours after application of the extracts) were evaluated. The oviposition was observed after the third counting of the number of adults. The extract of leaves of M. pulegium showed repellence and oviposition deterrence to B. tabaci biotype B and may be recommended as an alternative in the insect management.