Maize lethal necrosis disease: Evaluating agronomic and genetic control strategies for Ethiopia and Kenya

Maize lethal necrosis disease (MLN) was first diagnosed in eastern Africa in the 2010's and is a big threat to their maize-based agri-food systems with estimated losses amounting to US$261 million in Ethiopia and US$198 million in Kenya. This paper reviews the agronomic and policy options to contain MLN and comparatively analyzes the feasibility of using maize-bean rotations and MLN-tolerant germplasm as key alternative strategies for managing MLN. Results from crop simulation and economic surplus models are used to make assessments on what strategy offers the most realistic MLN control approach given the circumstances of smallholder production in Kenya and Ethiopia. The paper finds that although maize-legume rotations are sound agronomic recommendations and are crucial for long term maize production system viability, their widespread application over large geographic areas for MLN control is economically challenging given that maize is a preferred staple. We conclude that scaling MLN-tolerant germplasm proves highly viable with estimated multiplier benefits of US$245-756 million in Ethiopia and US$195-678 million in Kenya, and benefiting up to 2.1 million people in Ethiopia and 1.2 million in Kenya. Given that the threat of MLN is present and ongoing, the food and economic security of maize-based agrarian economies in eastern Africa will critically depend on the successful mainstreaming of MLN tolerance in their maize seed systems.