Report by Abigail Rumsey, Beatrice Uwumukiza and Bellancila Uzayisenga.
In the past two years, we have reported on the presence of the maize lethal necrosis (MLN) disease in East African countries including Kenya, Tanzania and Uganda. The disease is also present in South Sudan. The most recent report has been of its spread to the Northern Province of Rwanda.
Collaborative research by Rwandan and British agricultural research organisations, supported by Plantwise, confirmed that one of the two viruses of the maize lethal necrosis disease complex, Maize chlorotic mottle virus (MCMV), was present in maize samples from Rwanda in 2013. Three of the four samples were also confirmed to have the other MLN virus, Sugarcane mosaic virus (SCMV). It is proposed that SCMV is not new to the region, but MCMV is new, and is being spread, possibly by seed, throughout East Africa, leading to outbreaks of maize lethal necrosis.
This disease affects smallholder farmers as they can lose their entire crop of maize in a season. Symptoms include dying leaves, lack of pollen production, malformed ears, and rotting cobs. Progress is being made towards development of a resistant variety, with early indications that some hybrids are showing signs of resistance.
More information about the pests and viruses associated with maize lethal necrosis and the management of the disease can be found on the Plantwise Knowledge Bank.
Adams, I., Harju, V., Hodges, T., Hany, U., Skelton, A., Rai, S., Deka, M., Smith, J., Fox, A., Uzayisenga, B., Ngaboyisonga, C., Uwumukiza, B., Rutikanga, A., Rutherford, M., Ricthis, B., Phiri, N., & Boonham, N. (2014). First report of maize lethal necrosis disease in Rwanda New Disease Reports, 29 DOI: 10.5197/j.2044-0588.2014.029.022