The infection of Conotrachelus humeropictus Fiedler, a serious pest of cocoa and cupuaçu fruit in the Brazilian Amazon, by Metarhizium anisopliae and Beauveria bassiana was evaluated. The research was conducted in a field station of the Comissão Executiva do Plano da Lavoura Cacaueira - CEPLAC, in Ouro Preto d'Oeste, Rondônia. Suspensions of 3.93 χ 1010 conidia/ml of M. anisopliae and 4.26 χ 1010 conidia/ml of B. bassiana were superficially sprayed on soil in PVC flasks. One, three, seven and fourteen days after spraying the last larval instar were released. Beauveria bassiana was more eficient (52.0% mortality) than M. anisopliae (42.7%). The mortalities were the same for larvae liberated until the 7th day after contamination, and were significantly lower on the 14th day. The decline in the efficacy of the pathogens may be related to the presence of antagonic organisms in the soil.
Biological control; insecta; Theobroma cacao; Theobroma grandiflorum