Chemical control of the soybean caterpillar, in field conditions of Mato Grosso do Sul

Este trabalho mostra a eficiência de diversos inseticidas aplicados em pulverização sobre a Anticarsia gemmatalis Hüb. 1818, e sua atuação sobre os inimigos naturais da praga, e sua ação residual em condições de campo. Os produtos empregados, com suas respectivas dosagens em g i.a/ha, foram: Bacillus thuringiensis (500), carbaril (200), clorpirifós etil (240), diflubenzuron (25), endosulfan (175), fenitrotion (500), paration metil (200), monocrotofós (200), triclorfon (400), triazofós (200), endrin (200) e malation (500). Houve eficiência de quase todos os tratamentos doze horas e dois dias após a aplicação dos inseticidas em amostragens realizadas no pano; apenas o Bacillus thuringiensis, diflubenzuron e malation não mostraram bons resultados. Os produtos clorpirifós etil, diflubenzuron, endosulfan, triazofós e endrin foram eficientes até sete dias após a aplicação, com eficiência acima de 80% sobre as lagartas provenientes de uma nova geração. O diflubenzuron, embora não tenha apresentado bom resultado inicial, foi o que mostrou maior efeito residual sobre as lagartas no campo. Os inimigos naturais mais comuns encontrados foram Geocoris sp., Nabis sp., Fodisus sp. e aranhas. A ação dos inseticidas sobre esses predadores não pôde ser bem observada neste experimento.This paper shows how effective were various insecticides applied in spray against Anticarsia gemmatalis Hüb. 1818, as well as their action on its natural enemies and their residual action in field conditions. The products used, with their respective rates in g a.i/ha, were: Bacillus thuringiensis (500), carbaryl (200), ethyl chlorpiriphos (240), diflubenzuron (25), endosulfan (175), phenitrothion (500), methyl parathion (200), monocrotophos (200), trichlorphon (400), triazophos (200), endrin (200), and malathion (500). Some effectiveness was registered in almost all treatments, both twelve hours and two days after the application of the insecticides. Only Bacillus thuringiensis, diflubenzuron and malathion did not show good results. The products ethyl chlorpiriphos, diflubenzuron, endosulfan, triazophos and endrin were effective until seven days after the application, with effectiveness about 80% against the caterpillars originated from a new generation. Diflubenzuron, although it had not shown good initial results, was the only one which showed major residual effect against the caterpillars in the field. The most common natural enimies were Geocoris sp., Nabis sp., Podisus sp., and spiders. The action of the insecticides against them could not be clearly observed in this experiment