Population dynamics of stored maize insect pests in warehouses in two districts of Ghana

Understanding what insect species are present and their temporal and spatial patterns of distribution is important for developing a successful integrated pest management strategy for food storage in warehouses. Maize is stored in bags in warehouses in many countries in sub-Saharan Africa, but little monitoring information is available on insect activity in those warehouses. We monitored the populations of major post-harvest insect pests of maize at three different warehouses (MiDA, Gundaa and Wienco) in two regions in Ghana (Middle Belt and Northern Belt). The study was conducted from September 2015-July 2016, which represents a common maize harvest and storage period in the two regions. The most abundant insect pest found in the warehouses was Plodia interpunctella (Hübner), but other major pest species were recovered during the study. Sitotroga cerealella (Oliver) and Prostephanus truncatus (Horn) which are major pests on farms, were more likely to be captured in traps outside or at nearby farms than inside the warehouses. When recovered inside they tended to be found in the receiving and cleaning areas. Sitophilus spp. were commonly captured in the warehouses, but were more abundant in the Middle Belt warehouse. Our results identified the major species found during warehouse storage of maize in Ghana and suggest that the specific pest species may be different in warehouses compared to on-farm storage.