Simultaneous Use of Entomopathogenic Fungus Beauveria bassiana and Diatomaceous Earth against the Larvae of Indian Meal Moth, Plodia interpunctella

The suppressive ability of entomopathogenic fungus Beauveria bassiana alone and in combination with diatomaceous earth (DE) was studied against the larvae of Indian meal moth, Plodia interpunctella (Hübner) (Lep., Pyralidae). This study clearly showed that simultaneous use of B. bassiana and DE against larvae of P. interpunctella, not only could reduce the required concentration of fungal conidia or DE, but also could shorten the time need for showing insecticidal effects. The LC50 value of fungus at 7 d after treatment was 9.8 × 105 conidia mg-1 diet. Larvae showed a dose response to B. bassiana, and the addition of diatomaceous earth at 500 and 2000 ppm resulted in a significant increase in mortality. Larval mortality reached to the maximum of 28.3% and 71.7% after 7 d exposure to 500 and 2000 ppm DE concentrations, respectively. The LC50 value for B. bassiana in the presence of DE 500 ppm was 4.6 × 104 con. mg-1 diet and of DE 2000 ppm was 1.65 × 103 con. mg-1 diet. According to our results, B. bassiana and DE can be considered as two suitable candidates for integration into IPM strategy.