Potential distribution of fall armyworm in Africa and beyond under present and future climate change scenarios

The lepidopteran insect pest fall armyworm (Spodoptera frugiperda, FAW) first invaded Africa in 2016 and has since become established in many areas across the continent where it poses a serious threat to food and nutrition security. This study uses a CLIMEX model to estimate the potential FAW global invasion threat, with emphasis on risk of transient and permanent population establishment in Africa under current and predicted future climates. The model was fitted using eco-physiological tolerances of FAW and its occurrence records. The future potential distribution was predicted using A1B climate change scenario for 2030,2050, and 2080 under CSIRO-Mk3.0 and MIROC-H Global Climate Models. Our results suggest that FAW can establish itself in almost all countries in eastern and central Africa and in a large part of western Africa under the current climate. Climatic barriers, such as heat and dry-stresses, may limit the spread of FAW to North and South Africa. Furthermore, our projections suggest that the pest’s invasive range will retract in both northern and southern regions towards the equator under predicted future climates. However, a large area in eastern and central Africa is predicted to have an optimal climate for FAW persistence. These areas serve as FAW ‘hot spots’ from where it may migrate to the north and south during winter seasons and then pose an economic threat. Our projections can be used to identify countries at risk for permanent and transient FAW-population establishment and inform timely integrated pest management interventions under present and future climate in Africa.