Assessing efficacies of insect pest management methods for stored bagged maize preservation in storehouses located in Nigerian markets

Samuel I. Nwaubani, Grace O. Otitodun, Shekinat K. Ajao, George P. Opit,, Adeola A. Ala, Mobolaji O. Omobowale , Jonathan C. Ogwumike, Grace I. Abel, Moses O. Ogundare, Jafar A. Braimah, Busari S. Gbenga , Akhere E. Olenloa , Olumuyiwa R. Kolayemi , Samuel G. McNeill, Klein E. Ileleji 

Received 25 September 2019 Received in revised form
23 December 2019
Accepted 30 December 2019 

Abstract: Stored product insect pests cause significant losses in maize in sub-Saharan Africa (SSA). Control of these pests with conventional insecticides is fraught with health and environmental risks. Globally, several reduced-risk methods have been deployed as alternatives to conventional insecticides. In this study, conducted in FebruaryeDecember 2016, efficacies of five treatments to control insects in bagged maize stored in Nigerian market storehouses were evaluated. Treatments included a botanical (Piper guineense), Bularafa diatomaceous earth (DE), permethrin powder (RamboTM), PICS (hermetic) bags and ZeroFly® bags. The study also had a negative control comprising untreated maize in polypropylene bags. Study locations were in three grain markets, namely Eleekara market in Oyo town and Arisekola market in Ibadan, Oyo State, South West Nigeria, and Ago market in Ilorin, Kwara State, North Central Nigeria. Except in the case of PICS bags, each storehouse had six 100-kg bags for each storage method or treatment; these bags were sampled monthly. For PICS, each storehouse had 18 bags (~80 kg each) and six were destructively sampled every 4 months. Psocids (total 3,614) and S. zeamais (total 1,255) were the most abundant types of insects found during the study. However, among all treatments, PICS bags were the most effective at mitigating population growth of all species of stored product insects encountered, and the number of psocids and S. zeamais found in PICS bags during the entire study were 0 and 8, respectively. The order of effectiveness of the treatments were PICS > Permethrin > ZeroFly > DE > Botanical > control. Data showed PICS, Permethrin, ZeroFly, and DE when used according to manufacturer’s instructions or label are effective and can be incorporated in integrated pest management of stored-product insects in maize storehouses. More research is required to explore how P. guineense can be made more efficacious.