First Trial to Assess Gamma-Irradiation and Diatomaceous Earth Combination on Mortality of some Stored Product Insects

Abstract

This study was designed to characterize the combination of gamma-irradiation and food grade diatomaceous earth (Wolf Creek ranch, California, USA) as diatomaceous earth formulation treatment against three of stored product insect pests [Sitophilus granarius (L), Tribolium castaneum (Herbst.) and Rhyzopertha dominica, (F)] in the laboratory. The study was assessed the killing effect of gamma-irradiation at 50,100 and 250 Gray against these pests. As well as 0, 0.5, 1.0 and 1.5 g/kg (w/w) concentrations of diatomaceous earth formulation alone or in combination with irradiation were assessed. The obtained results indicated that the mixing between two insect control methods had the combined advantages of quick speed of killing and a high level of safety. Where, the LT50 have a wide range of values and the combined treatments of gamma-irradiation and treatment with diatomaceous earth maybe were the most influencing factors reducing lifespan after treatments. In this laboratory study the combination between diatomaceous earth (1.5 g/kg) and irradiated the tested pests with (250 Gy) of gamma ray produced an antagonistic interaction, except in the case of Rhyzopertha dominica F. adults. Our finding stated that the use of ‘control method’ gamma-irradiation in conjunction with diatomaceous earth could be a feasible strategic component in Insect Pest Management; IPM in operational modality might be ‘sequential’ against the tested pests. That is to apply irradiation to eliminate existing census personnel. This is then followed by the addition of DE to the grain to prevent the infection from occurring again