Eco-friendly control of rice weevil, Sitophilus oryzae L. (Coleoptera, Curculionidae) in grain storage structures using diatomaceous earth admixed insecticides

Abstract

Sitophilus oryzae infestation results in the low nutritional and commercial value of stored grains. Surface treatment of storage structures can effectively kill harbouring weevils. The indiscriminate and frequent application of structural insecticides causes a threat to the environment and human health along with insecticidal resistance development. There is a dire need to discover safe natural compounds for increased efficacy along with prolonged control of S. oryzae. This study proposes a combination of diatomaceous earth with conventional and novel insecticide for environmentally safe pest management. Admixing diatomaceous earth with conventional and novel insecticides resulted a significant increase in their efficacies where their LC50 values decreased at least by >80% and 40%, respectively. The highest synergism was observed (>80% decreased LC50) in DE and deltamethrin mixtures 48 and 72 hours after application. Our findings suggest that diatomaceous earth, being a natural compound and relatively safer for human and livestock health with no persistent toxicity in grains, can provide an environmentally safe option to synergise conventional insecticides for structural and grain treatments.