Integrated pest management in post-harvest maize: a case study from the Republic of Togo (West Africa)

Abstract

A large-scale experiment on maize storage systems was carried out in Atakpamé (Plateaux region of Togo), between autumn 1996 and spring 1997. An integrated pest management (IPM) approach based on research findings at the International Institute of Tropical Agriculture (IITA) and intended to control insect pests in rural maize stores was compared with (1) the locally prevalent methods of storage of farmers from the Plateaux region and (2) with the storage system recommended by the National Plant Protection Service in Togo (SPV). Two storage systems were designed based on IPM principles, one using a local variety (chosen mainly for its excellent husk cover characteristics), the second including an improved variety (with higher yield and moderately good husk cover characteristics), and both depending on visual selection of cobs at harvest to reduce initial insect infestation. The experiment was conducted in a collaborative manner, including representatives of the SPV, farmers from the Plateaux region, and researchers from IITA. Population dynamics of major insects and associated losses to stored maize were monitored monthly over an 8-month period, while an on-site evaluation of pest infestation and losses was conducted after 6 and 8 months of storage. The performance of the different storage systems was evaluated in terms of pest densities, grain weight losses and cost-efficiency. The IPM-based systems were as effective as the pesticide-based SPV system in reducing infestation and grain losses. When only the incremental net returns from the storage practices were considered, both the IPM approach and the recommendations of the SPV performed better than the farmers’ methods of storage. However, when the yields (per hectare) of the different maize varieties used in the respective storage systems were included in the cost and return analysis, the IPM storage systems using the local variety performed worse.