The insecticidal efficacy of the Diatomaceous earth formulation Dryacide® against two Lepidopteran stored product pests

Environmental problems and threats to human health due to the use of synthetic pesticides have increased the demand for safe biological insecticides. DE is an effective alternative to chemical pesticides to control stored product pests. In this study, the insecticidal effect of Dryacide^® (a commercial formulation of diatomaceous earth) was studied on second and third larval instars of the Mediterranean flour moth and Indian meal moth. Experiments were performed at 27±2ºc, 45±5% RH and continual darkness. Second and third larval instars were exposed to 40 g of wheat treated by various concentrations of diatomaceous earth. Larval mortality was assessed 7 and 14 days after exposure. The results indicated that the mortality was increased by increasing the concentration of Dryacide^®. The LC₅₀ values for second and third larval instars of the Mediterranean flour moth and Indian meal moth after 7 days were 116.3, 261.03, 43.58, 312.13 ppm and after 14 days were 20.06, 236.55, 13.82, 305.07 ppm, respectively. These results showed a promising potential for Dryacide^® to control these stored product pests.