Maize lethal necrosis disease

This disease is spreading by insects that eat corn. This disease causes severe systemic necrosis which ultimately leads to plant death. In Kenya there is a 50-90% reduction in harvest, and production is completely lost in some areas.

Effective control of two corresponding plant diseases at the seed level can reduce the possibility of developing deadly necrotizing disease in corn. The seed inspector can investigate corn-lethal necrosis, corn aortic plaque virus and sugarcane mosaic virus in the seed farm

Likewise, by monitoring and managing the transport of corn crops it is possible to suppress the spread of fatal necrosis of corn. In addition, it is possible to breed corn cultivars that are relatively resistant to diseases that cause fatal necrosis of corn.

Maize lethal necrosis (MLND) is a combination of two viruses, one of corn chlorotic mottle virus (MCMoV) and a group of Potyviridae such as sugar cane mosaic virus (SCMV), wheat streak mosaic virus (WSMV) Results. ) Or corn atrophy mosaic virus (MDMV). Dual infection of these two viruses results in so-called MLND, also known as corn-killed necrosis (CLN).

The symptoms of lethal necrosis of corn (Photo 1a and Photo 1b) are synergistic co-infections of the symptoms of corn and corn's chlorotic mottle virus (Photo 2) and viruses of Potyviridae family such as wheat streak mosaic virus, short corn It is caused by. Symptoms of mosaic virus or symptoms of sugar cane mosaic virus (original corn atrophic mosaic virus - B) (picture 3). Infections of each virus alone cause mild symptoms, but a synergistic reaction of corn mottle spot mosaic virus and arbitrary potato virus complex infection causes plant death. In many cases it is known that symptoms of fatal necrosis in maize appear only with corn chlorotic mottle virus infection under abiotic stress conditions such as drought and low nitrogen.

A serious epidemic in Kenya was later diagnosed as fatal necrosis of corn and was first reported in Longisa branch in Bomet district in September 2011. By 2012, symptoms consistent with fatal necrosis of corn were observed in parts of Central Kenya, Ni Ansa, West and Rift Valley. Since then, Rwanda and the Democratic Republic of the Congo have reported this disease. Similar corn symptoms have been reported in Uganda and Tanzania and more recently in South Sudan and Ethiopia. Recent discussions with pathologists in Tanzania have cast doubt that the disease may have occurred in Tanzania's Mtwara, Tanzania, bordering northern Mozambique

Experimental hosts involved in lethal necrosis of maize are limited to the grass (grass) family, as maize is the primary and natural host. Using mechanical vaccination, many natural and cultivated plants are infected with one or both viruses. , Digitaria sanguinalis, Eragrostis trichodes, Hordeum species. , Panicam spp. , Setaria spp. , Sorghum seed. And wheat (Triticum aestivum). This will determine the range of potential vaccination pools for various viruses that may cause fatal maize necrosis in South Africa. This will involve investigating grasses in highly dangerous areas and screening previously reported maize virus grasses.