Remote sensing of crop health for food security in Africa: Potentials and constraints

Global food security, as determined by the balance of global food production and demand in the face of rapid increase in climate change effects, diseases and pests, has become a critical issue in recent years. From a global to local scale, food production is facing challenges from crop diseases and pests, which have the potential to affect a wide range of crops, and result in significant yield losses. Accurate and timeous detection, mapping and monitoring of crop diseases and pests is critical for food security, particularly in sub-Saharan Africa where hunger and poverty have reached alarming stages. Recent developments in high resolution remotely sensed data has seen a great potential in mapping cropland areas infected by pests and diseases, as well as potential vulnerable areas over expansive areas. This paper provides a review on the developments in remote sensing and its potential to estimate and map pest and disease infestation. The review shows that large scale crop diseases and pests mapping and monitoring using remote sensing techniques remains a major challenge. Consequently, the inherent trade-offs between image resolution, spatial coverage, acquisition costs, optimal predictions and high classification accuracies in crop monitoring hinder effective remote sensing applications in monitoring crop diseases and pests, especially in poor economies.