The Efficacy of Two Plants Insecticides for the Control of Maize Weevil (Sitophilus Zeamais) in Maize (Zea Mays) At Storage in Lafia , Nasarawa State, Nigeria

Abstract

A study was conducted in the Agronomy Laboratory of College of Agriculture, Science and Technology, Lafia between June and July 2025 to investigate the ‘Efficacy of Mahogany and Neem oil extracts for the control of Maize weevils (Sitiphilus zeamais) on maize at storage. Whole grain of white maize variety (a composite hybrid maize type) was used for the experiment. Maize weevils Sitophilus zeamais were collected from infested wild maize stored since 2024.Ten (10) adults’ maize weevils each were released into ten (10) glass jars (500ml capacity) containing 200g of conditioned grain each. The laboratory condition has an ambient temperature of 220-240C and a relative humidity of 77% which is favourable for the development of progenies of different sexes. Oil from the Neem (Azadirachta indica A. Juss) and Mahogany (Swietenia mahagoni spp) are naturally occurring pesticides and are extracted through solvents Soxlet extraction and maceration using n-hexane solvent for 3- 24 hours respectively with three different solvents (Acetone, ethanol and distilled water) at 350C by shaking at 150rpm within three (3) hours. The obtained oil of neem which contains Azadirachtin and mahogany which contains Linoleic acid were thoroughly mixed with the seeds at a concentration of 1%,2%,3%, and 0 % levels with the 200g seeds of maize respectively. Neither the Neem oil or mahogany oil were applied to the 0% level (control). After four (4) weeks, the number of dead and live insects were removed, and the percentage (%) weight loss, and percentage (%) seeds damaged were assessed. Damaged %=Damaged grains/ total grains x 100. Weight loss % =Und-Dnu/U(nd+nu) x100.The result of the experiment revealed that mahogany oil extracts was found to have a significant effect in reducing the population of Sitophilus zeamais. The order of three concentrations and a control to protect the seed weight loss will be in the order,3%>2%>1%>0%.

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