ATIVIDADE INSETICIDA DE ÓLEOS VEGETAIS SOBRE Sitophilus zeamais MOTS. (COLEOPTERA: CURCULIONIDAE) EM MILHO ARMAZENADO

Abstract

Oils of andiroba (Carapa guianensis Aubl.), copaiba (Copaifera sp.), Eucaliptus globulus Labill. and Eucaliptus citriodora Hook., neem (Azadirachta indica A. Juss), eugenol, souari nut (Caryocar brasiliense Camb.), rosemary (Lippia gracillis HBK.), and cedar (Cedrela fissilis Vell.) were evaluated in adults of Sitophilus zeamais Mots. (Coleoptera: Curculionidae). In the non-choice test, 20 g of corn grains per plot were treated with 50¿L of each oil and homogenized for two minutes. The plot was infested with eight 0 to 15 days-old S. zeamais adults. The E. globulus, eugenol, rosemary, and neem oils caused 100% mortality in S. zeamais adults. Except for copaiba, all oils caused mortality above 87% and the reduction in emergence of 100%. In the free-choice tests, arenas consisting of two plastic containers symmetrically interconnected to a central box by two plastic tubes were used. Twenty grams of non-treated corn (control) were placed in one of the boxes and the same amount of grain treated with 50¿L of each oil comprised the other treatment. Sixteen non-sexed S. zeamais adults (0-15 days old) were released in the central box. The rosemary, E. citriodora, eugenol and copaiba oils were the most repellent for S. zeamais adults, with repellence percentage varying from 97.3 to 87.7. Rosemary, andiroba, neem, and cedar reduced S. zeamais emergence in 100%, while the reduction caused by the other oils ranged from 72.7 to 97.9%.