Insecticidal Activity of Diatomaceous Earth against Sitophilus zeamais in Stored Maize Grains

Abstract

Sitophilus zeamais (Maize weevil) is an insect pest that has a global distribution and causes post-harvest losses that plague African agriculture, threatening food security and economic development. Despite this challenge, natural products can provide sustainable solutions. This paper aims to explore the Diatomaceous earth's insecticidal potency as natural alternative to chemical pesticides against the weevil by laboratory experimentation, on a 14-day exposure trial. The study involved the use of three (3) replicates at treatment doses of 0.5 g/kg, 1 g/kg, and 1.5 g/kg for diatomaceous earth. Forty (40) mature S. zeamais were exposed in each jar containing 50 g of the treated maize in dose replicates of the powder for 24 h on days 3, 7 and 14. Results showed that mortality was 100% and dose-dependent, except at 0.5 g/kg (96.52%), and there was also a significant difference in mortality rates of the weevil across all treatments (P ˂ 0.05). Following exposure to the powder, the maize weevil's decreasing LC50 of 0.377 g/kg confirms its effectiveness in killing the weevils. By exploring this natural pest control product tested within laboratory settings, we recommend further studies on the use of Diatomaceous Earth powder on mammalian toxicity, field validation, as well as farmers' application of the powder as a grain protectant in storage against the weevil.