Sustainable Storage Pest Management Using Diatomaceous Earth against Sitophilus oryzae L.

Abstract

The rice weevil, Sitophilus oryzae L., is a destructive internal feeder in stored grains of strategic crops in Egypt. Diatomaceous earth (DE) is a natural substance as a physical method free of toxic residues in the storage ecosystem. A laboratory experiment was conducted to study the impact of diatomaceous earth (DE) on the Sitophilus oryzae L. as well as on wheat seed germination. Various concentrations of DE were selected at 13, 11, 9, 7, 5, 3, 1, 0.5 and 0.25 mg in addition to the control treatment without DE. Mortalities in S. oryzae adults reached 100% at rates of 11 and 13 mg DE after 6 and 7 days of adult exposure compared to 0% mortality recorded in untreated grains. Furthermore, the treated grains with DE at 0.25 and 0.5 mg within 1 and 2 days of exposure were unable to protect the stored grains against S. oryzae,while the seventh day of exposure had effective results of protection. Seed germination was only tested on the treated wheat grains within 7 days of exposure. Results indicated that the germination rate was accelerated as it reached 99% at higher doses of DE (11 and 13 mg) compared to 53% in the untreated seeds. Agro-morphological characters of tested seeds were also highly improved. The seedling length reached 59.41 cm compared with 24.30 cm for untreated seeds. The seedling Vigor index at 13 mg DE was greater (5881.59) than the control (1287.9). The present work demonstrated the effectiveness of DE at 13 mg DE/100g on the 7 day of release to combat rice weevil in cereals storage environments on a sustainable basis. DE was found to be an ecofriendly physical method for sustainable pest management in the wheat storage ecosystem.