Abstract

The cowpea weevil, Callosobruchus maculates is a pest which mainly attacks beans from the genus  Vigna, standing out as the most important bean weevil in the Brazil’s Northeast, where most of beans planted belongs to this genus. This work had as objective to evaluate the pathogenicity of different isolates of Beauveria bassiana to controlCallosobruchus maculatus in adult phase under laboratory conditions. The adult insects, with 24 h age, were inoculated with seven isolates of B. bassiana (URM2916, URM2921, URM2923, URM2926, URM4544, URM4551, and URM4552) at concentrations of 10⁴, 10⁵, 10⁶, 10⁷ and 10⁸ conidia.ml^-1. Inoculation of fungic isolates was performed with manual micro pulverizer. Incubation was carried out at a climate room (28±2°C) and 75±5% relative humidity. Mortality percentage varied from 12.24 to 100% in the course of nine days experiment. The isolates of B. bassiana showed highly pathogenic, characteristic confirmed by mortality superior to 40% in the insects treated until to fourth day in all conidial concentrations tested. Among isolates studied, URM2921, URM2923 and URM4544, presented as the most virulent to the target-insect suggesting their use in programs of biological control of cowpea pest.

Key words: Biological control, entomopathogenic fungi, Beauveria bassiana, pathogenicity, Callosobruchus maculatus.