Maize Lethal Necrosis Disease (MLN Disease, MLND, Corn Lethal Necrosis) is a disease affecting maize (corn) chiefly in East Africa. It's caused by infection with two viruses, MCMoV (Maize chlorotic mottle virus) and one from the Potyviridae group: MDMV (Maize dwarf mosaic virus), WSMV (Wheat streak mosaic virus), SCMV (Sugarcane mosaic virus) and the like.
In late 2014, it was reported that MLND could cut Kenya's maize production by as much as 30%. In early March 2015, the middle of the rainy season, losses were estimated at 10%.
References
Maize Lethal Necrosis Disease Wikipedia(Text) CC BY-SA