Picadas de alimentação de Nezara viridula em cultivares e linhagens de soja de diferentes graus de suscetibilidade Stylet sheath op Nezara viridula in resistant and susceptible soybean varieties

• Main Authors: C. J. Rossetto, A. L. Lourenção, T. Igue, M. A. C. De Miranda
• Format: Article
• Language: English
• Published: Instituto Agronômico de Campinas 1981-01-01
• Series: Bragantia
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051981000100010

O número de vezes que o percevejo-verde Nezara viridula (L., 1758) (Hemiptera: Pentatomidae) se alimentou em cinco diferentes genótipos de soja foi estimado através das bainhas do estilete que permaneceram no local onde ele se alimentou. Foram feitas estimativas a olho nu, através de lupa sem corante e através de lupa após tratamento das vagens com corante de fucsina ácida, como foi proposto por BOWLING. A olho nu, notaram-se distintamente os locais das picadas nos cultivares Paraná e Hill e muito poucas picadas nas linhagens IAC 73/228 e IAC 77/656. A primeira geração do cruzamento entre 'Paraná' e IAC 73/228 apresentou comportamento intermediário, quando observada sem corante. Após tratarem-se as vagens com corante, ficou reduzida a diferenciação entre as linhagens IAO e os cultivares Hill e Paraná, enquanto a geração F1 deixou de ser intermediária e igualou-se aos cultivares suscetíveis. Os resultados sugerem a presença de um grau alto de tolerância à alimentação de percevejo nas linhagens IAC 73/228 e IAC 77/656.<br>The number of stylet sheaths of Nezara viridula (L., 1758) (Hemiptera: Pentatomidae) in 5 soybean (Glycine max (L.) Merrill) varieties was estimated under greenhouse conditions, at Campinas, State of São Paulo, Brazil. When estimated with naked eyes, the number of stylet sheaths was low in the varieties IAC 73/228 and IAC 77/656, high in the commercial varieties 'Hill' and 'Paraná' and intermediate in the F1 generation between Paraná and IAC 73/228. When estimated under the stereo microscope after staining the pods with acid fucsin, the number of stylet sheaths was high in the commercial varieties 'Hill', 'Paraná' and the F1. It was intermediate in IAC 73/228 and IAC 77/656. It seems from these results that a moderate degree of non preference for feeding might be present in the varieties IAC 73/228 and IAC 77/656, but further research is needed to support or to reject the existence of this moderate degree of non preference. The varieties IAC 73/228 and IAC 77/656 showed low stylet sheath counts when the pods were not stained and higher counts after staining. This suggests that they have high tolerance to the feeding activity of the green stink bug, not showing much reaction to its feeding activity. It is easier to notice the feeding punctures of the green stink bug on the pods of susceptible varieties than on resistant varieties. The variety IAC 73/228 has been previously shown to suffer low damage caused by green stink bug under field conditions. Both IAC 73/228 and IAC 77/656 are descendents of crosses involving the PI 274454 with the susceptible commercial variety 'Hill'. The Pi 274454 is probably a good source of resistance to the green stink bug. It is a vigorous, procumbent, late maturing variety from the Japanese island of Okinawa.