First record of the occurrence of the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) in Botswana

Abstract

The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) is an invasive alien insect pest in Africa originally from Central America. Although it is a pest of mainly stored maize grain and dried cassava roots, the larger grain borer is polyphagous, damaging a wide variety of other staple grains and non-agricultural forest and household products (e.g., wood and/or trees, leather, rubber). To-date, the pest has spread to over 21 countries in Africa since its first introduction in the 1970s. Stored maize grain losses have since doubled in these countries. In Southern Africa, the pest was first reported in Malawi (1991), then Zambia (1993), Namibia (1998), South Africa (1999), Zimbabwe (2005), and Mozambique (2007). Specimens of the pest sampled through pheromone baited traps on the outskirts of Gaborone, Botswana were morphologically identified and confirmed using molecular sequencing. Therefore, we make a first report on the occurrence of the larger grain borer in Botswana and recommend urgent and concerted efforts to monitor the pest, update databases on the extent of its geographical distribution, host range (crop and noncrop products, including its prospective biosecurity threats and risks), socio-economic impacts and strategies for containing and managing this invasive quarantine pest.