Maize Lethal Necrosis Disease: an Emerging Problem for Maize Production in Eastern Africa

Maize Lethal Necrosis Disease: an Emerging Problem for Maize Production in Eastern Africa

Maize is a staple food for over 70 million peoples in Africa, and predominantly produced and consumed directly by small scale holder families. Maize Lethal Necrotic Disease (MLND) is a new disease in East Africa, first reported in Kenya in 2011 and then spread to Tanzania, Uganda, Rwanda and Ethiopia. The disease is caused by Maize Chlorotic Mottle Virus (MCMV) in combination with viruses of the genus Potyvirus, mostly Sugarcane Mosaic Virus (SCMV), Wheat Streak Mosaic Virus (WSMV) or Maize Dwarf Mosaic Virus (MDMV). The co-infection is the one that results in intensive to complete yield loss. The disease causes symptoms ranging from leaf tissue mottling and malformed ears to premature plant death. MLND develops from synergistic co-infection by Sugarcane Mosaic Virus and Maize Chlorotic Mottle Virus. Diagnosis of MLND based on symptoms is reported ineffective because symptoms like stunting and chlorosis resembles nutrient deficiencies or maize mosaic. Detection and characterization of MLND causing viruses have been done by techniques such as enzyme-linked immuno-sorbent assay (ELISA), polymerase chain reaction (PCR) and next generation sequencing. Relatively little work has been done to identify and characterize MLND causing viruses in East Africa. The disease can be managed through the use of certified seeds, sanitation, quarantine, crop rotation, the use of resistant/tolerant maize varieties and other cultural practices. The use of resistant maize varieties is considered the most reliable, ecofriendly, effective and economical way of managing MLND.