The susceptibility of two isolates of Beauveria bassiana (Bals.) Vuill. against Sitophilus oryzae (L.), S. zeamais (Motsch.) and Rhyzopertha dominica (Fabr.) was determined. Boxes containing stored rice previously inoculated with conidia of two B. bassiana isolates were infested with the three insect species and maintained at 26 ± 0.5°C, 70 ± 10% of RH, and photophase of 12 hours. Ali three species were susceptible to both fungal isolates. Both isolates were efficient against S. oryzae, at the concentration of 0.5 g conidia/ 100 g of grain. The isolate 604 was the most efficient against S. zeamais, at the concentration of 0.1 g conidia/100 g of grain. Dosages of 0.0l g (isolate 476) and 0.05 g (isolate 604)/100 g of grain provided high mortality leveis of R. dominica, confirming the higher susceptibility of this species to the pathogen.
Insecta; stored grain pests; entomopathogenic fungi; microbial control
