Biocontrol of Acanthoscelides obtectus and Sitophilus oryzae with diatomaceous earth and Beauveria bassiana on stored grains

Combined treatment with Beauveria bassiana, and diatomaceous earth (DE) was evaluated against the bean weevil Acanthoscelides obtectus and rice weevil Sitophilus oryzae. DE from Argentina was screened both alone or in combination with water or dry fungal formulations. DE killed 100% of A. obtectus and 68% of S. oryzae showing a significantly higher insecticidal effect than the fungal dust. For A. obtectus, median lethal time (MLT) with the DE-dry fungus was significantly lower than with a fungal aqueous-suspension. In S. oryzae, powder formulations with either of B. bassiana or DE showed a MLT significantly higher than the wet treatments.