First report of maize lethal necrosis in Ecuador
Maize lethal necrosis is an emerging disease of maize (Zea mays) crops in Africa (EPPO RS 2015/147) which is caused by a combination of Maize chlorotic mottle virus (Machlomovirus, MCMV) and either a maize-infecting Potyviridae, such as Sugarcane mosaic virus (Potyvirus, SCMV), Maize dwarf mosaic virus (Potyvirus, MDMV), or Wheat streak mosaic virus (Tritimovirus, WSMS). In addition to Africa, maize lethal necrosis disease has been observed in Yunnan province in China. In South America, symptoms of maize lethal necrosis had not been observed until recently, although SCMV has been documented as early as 1914 and the earliest reports of MCMV date back to the 1970s in Peru and Argentina, and later in Colombia. Since 2013, severe virus-like symptoms have been reported in Ecuador, in the two major maize-producing provinces of the country (Manabí and Los Ríos). Affected maize plants showed symptoms of severe mosaic, chlorosis, and in some cases, necrosis. In May 2015, samples were collected from symptomatic maize plants and tested. Molecular analysis revealed the presence of SCMV and MCMV, two components of maize lethal necrosis. This is the first time that maize lethal necrosis is reported from Ecuador and from South America.
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