Effect of Paecilomyces fumosoroseus (Wise) Brown and Smith (Ascomycota: Hypocreales) alone or in combination with diatomaceous earth against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) and Ephestia kuehniella Zeller (Lepidoptera: Pyral

The insecticidal effect of the entomopathogenic fungus Paecilomyces fumosoroseus (Wise) Brown and Smith (Ascomycota: Hypocreales) was evaluated against adults and larvae of the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) and larvae of the Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). The fungus was added in stored wheat at two dose rates, 200 and 400 ppm, at two temperature levels, 20 and 25 °C alone or in combination with the diatomaceous earth formulation SilicoSec®. Mortality of the exposed individuals was measured after 7, 14 and 21 d of exposure. For both T. confusum adults and larvae, mortality was higher at 20 than at 25 °C. In the case of T. confusum larvae, after 14 d of exposure, mortality on wheat treated with the highest dose of P. fumosoroseus with SilicoSec® was significantly higher than that of SilicoSec® or P. fumosoroseus alone. At 20 °C larval mortality was 100% after 21 d of exposure in both fungal doses with SilicoSec®. In contrast, mortality of T. confusum adults was low and did not exceed 34% in any of the treatments tested. Finally, mortality of E. kuehniella larvae did not exceed 56%, while SilicoSec® alone caused higher mortality in comparison with the other treatments.