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Research Project: Developing Genomic and Biological Resources to Characterize, Diagnose and Detect Emerging and Invasive Vectored Bacterial and Viral Plant Pathogens for Safeguarding U.S. Agriculture

Location: Foreign Disease-Weed Science Research

Title: Maize lethal necrosis

item Stewart, Lucy

Submitted to: CABI Crop Protection Compendium
Publication Type: Other
Publication Acceptance Date: 10/5/2022
Publication Date: 12/21/2022
Citation: Stewart, L.R. 2022. Maize lethal necrosis. Electronic Publication. CABI Invasive Species Compendium, factsheet 119663.

Interpretive Summary: Maize lethal necrosis (MLN) is an emergent global disease caused by mixed infection of maize chlorotic mottle virus (MCMV) with any of several maize-infecting viruses classified in the family Potyviridae. Originally described in Kansas, USA in 1978, MLN has emerged since 2011 in Asia, sub-Saharan Africa, and South America, driven by expanding distribution of the MCMV component to locations where potyviruses were already present. MLN has devastating consequences to agriculture, especially where maize is cultivated intensively for human consumption. This work is an update to an international factsheet to be made available online, presenting basic and practical knowledge of MLN, its viral components, and management options. This information will be made available to a global audience to provide readily accessible information and resources based on cited scientific literature.

Technical Abstract: Maize lethal necrosis (MLN) is caused by synergistic mixed infection with any of several maize-infecting viruses from the family Potyviridae and the unrelated machlomovirus, maize chlorotic mottle virus (MCMV). This synergistic disease was originally described in Kansas, USA in 1978, as the synergistic mixed infection of MCMV with maize dwarf mosaic virus (MDMV) or wheat streak mosaic virus (WSMV), and named corn lethal necrosis (CLN), now referred to as MLN. MCMV or potyvirus infection alone cause mosaic and mild to moderate stunting, while mixed infection of both results in characteristic leaf margin and apical necrosis, severe stunting and mosaic, and highly elevated MCMV titers. One or more maize-infecting potyviruses such as sugarcane mosaic virus (SCMV) and MDMV are endemic in maize throughout the world. Thus emergence of MLN since ca. 2011 is driven by expanding distribution of MCMV. MCMV was first described in Peru in 1971, then in the continental USA with the discovery of MLN (1970s), and was later reported in Argentina, Thailand, and Mexico (1980s) and Hawaii, USA (1990s), where researchers first identified corn thrips (Frankliniella williamsi) ( as a major vector. Post-2010, MCMV and MLN have emerged in Asia, East Africa, Europe, and South America, associated with corn thrips and intensive maize cultivation.