Evaluation of indigenous methods for the control of the maize weevil sitophilus zeamais (coleoptera: curculionidae) in stored maize

Abstract

A survey carried out in three divisions of Bungoma district, Western Kenya, confirmed that Sitophilus zeatnais was the predominant pest in the farm stores. Of the 100 farmers interviewed, 9g% stored maize on their farms, of which 99% experienced insect pests in their storage systems. The farmers, gO.2% estimated losses incurred due to Sitophilus zeamais to be 2-4kgs/90kg bags. About a third of the farmers, 34% applied indigenous practice lor the control of S. zeaniais, despite limitations associated with these practices such as undefined dosage rate, sensitivity to high moisture content, tedious in preparation, unreliability in efficacy and reduced germination rate of planting seeds. The efficacy of kensil super Cine (Diatomceous earth), maize cob ash, and bean trash ash and neern seed cake powder was tested against adult Sitophilus zeamais in comparison to actellic dust®( pirimiphos-methyl) , Spintor dust" (spinosad), dryacide" and untreated maize, which acted as the controls. The effectiveness of the dusts was directly related to the dosage. Neem seed cake powder was ineffective «10% mortality) while bean trash ash, 80.2%, maize cob ash, 84.2% and kensil superfine, 85.5% achieved unsatisfactory control of S zeamais. Pirimiphos - methyl and dryacide achieved 100 and 98% mortality, respectively. The efficacy of the dusts tested was reduced by the increased grain moisture content. Apart from neem seed cake powder, the dusts tested conferred protection for six months, and only dryacide adequately protected the grain up to 9 months. Since moisture content plays a critical role in the efficacy of dusts, it is important that farmers should manipulate it in order to achieve desired results in storage. Application of indigenous technical strategies will be ideal in the management of Sitophilus zeamais when incorporated in the [PM system at the farm level.