Maize lethal necrosis disease
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- List of Symptoms/Signs
- Biology and Ecology
- Economic Impact
- Environmental Impact
- Social Impact
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Maize lethal necrosis disease
Other Scientific Names
- Corn lethal necrosis disease
- Maize chlorotic mottle virus
- Sugarcane mosaic virus
Taxonomic TreeTop of page
- Domain: Virus
- Unknown: "Positive sense ssRNA viruses"
- Unknown: "RNA viruses"
- Unknown: Maize lethal necrosis disease
Notes on Taxonomy and NomenclatureTop of page
Maize lethal necrosis disease is caused by co-infection of maize by Maize chlorotic mottle virus (Machlomovirus: Tombusviridae) and Sugarcane mosaic virus (Potyvirus: Potyviridae) or sometimes another cereal virus of the Potyviridae group.
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|-Yunnan||Present||Introduced||2010||Xie et al., 2011|
|Ethiopia||Present||Mahuku et al., 2015|
|Kenya||Widespread||Introduced||2011||Wangai et al., 2012; Kusia et al., 2015; IPPC, 2017||First reported in September 2011, at lower elevations (1900 masl) in the Longisa Division of Bomet County, Southern Rift Valley of Kenya. Later the disease was noted in Bomet Central Division, spreading into the neighbouring Chepalungu and Narok South and North Districts and Naivasha. By April 2012, the disease was reported in altitudes up to 2100 masl and in various parts of the country. Currently the disease has been reported in all provinces in Kenya except North Eastern.|
|Rwanda||Present||Adams et al., 2014|
|Tanzania||Present||Introduced||2012||Makumbi and Wangai, 2013||Mwanza and Arusha regions|
|Uganda||Present||IPPC, 2014||Preliminary report|
|Mexico||Present||Carrera-Martinez et al., 1989|
|USA||Present||Present based on regional distribution.|
|-Hawaii||Present||1990||Jensen et al., 1990; Jiang et al., 1990; Ooka et al., 1990||The disease appeared in Kaua’i in early 1990. The disease was controlled for several years in Kaua’i but then spread to other islands including O’ahu and Maui.|
|-Kansas||Present||1976||Niblett and Claflin, 1978||First discovered in a corn field in North Central Kansas then in Almena Kansas. The disease is now endemic in North Central Kansas.|
|-Nebraska||Present||1976||Doupnik, 1979; Uyemoto, 1983||Endemic in South Central Nebraska where affected fields are located in small river valleys and irrigation districts.|
|Argentina||Gordon et al., 1984|
|Peru||Present||1974||Castillo and Hebert, 1974|
Hosts/Species AffectedTop of page
The experimental host range is restricted to the Poaceae with maize as the main a natural host (Gordon et al., 1984). The following species have been infected by mechanical inoculation: Bromus spp., Digitaria sanguinalis, Eragrostis trichodes, Hordeum spp., Panicum spp., Setaria spp., Sorghum spp. and Triticum aestivum (Castillo and Hebert, 1974; Niblett and Claflin, 1978; Bockelman et al., 1982) and Zea mays subsp. mays and mexicana (Castillo and Hebert, 1974; Nault et al., 1982). The Kansas serotype 1 also infected Zea mays subsp. parviglumis and Zea luxurians (Nault et al., 1982).
Host Plants and Other Plants AffectedTop of page
Growth StagesTop of page Flowering stage, Fruiting stage, Seedling stage, Vegetative growing stage
SymptomsTop of page
Maize chlorotic mottle virus (MCMV) causes a variety of symptoms in maize depending upon genotype, age of infection and environmental conditions. They range from a relatively mild chlorotic mottle to severe stunting, leaf necrosis, premature plant death, shortened male inflorescences with few spikes, and/or shortened, malformed, partially filled ears (Castillo and Herbert, 1974; Castillo Loayza, 1977; Niblett and Caflin, 1978; Uyemoto et al., 1981).
When MCMV co-infects maize with a potyvirus, the infected plants in the field show a diverse range of symptoms. Diseased plants develop symptoms characteristic of virus diseases. There is chlorotic mottling of the leaves, usually starting from the base of the young leaves in the whorl and extending upwards toward the leaf tips. The leaves can experience necrosis at the leaf margins that progress to the mid-rib resulting in drying of the whole leaf. If there is necrosis of young leaves in the whorl before expansion, then 'dead heart' symptoms will be visible. Other symptoms include premature aging of the plants and mild to severe leaf mottling. Severely affected plants form small cobs with little or no grain set. The entire crop can frequently be killed before tasseling (Niblett and Claflin, 1978; Uyemotoet al., 1980, 1981; Wangai et al., 2012).
List of Symptoms/SignsTop of page
|Growing point / dead heart|
|Leaves / abnormal colours|
|Leaves / abnormal patterns|
|Leaves / necrotic areas|
|Leaves / yellowed or dead|
|Seeds / mould|
|Stems / dead heart|
|Stems / dieback|
|Stems / stunting or rosetting|
|Whole plant / dead heart|
|Whole plant / early senescence|
|Whole plant / plant dead; dieback|
Biology and EcologyTop of page
Maize lethal necrosis was first identified in the USA in 1976 (Niblett and Caflin, 1978). The disease is caused by a combination of two viruses, Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV), a pathogen prevalent in many parts of Kenya affecting cereal crops. The double infection of MCMV and SCMV or any of the cereal viruses in the Potyviridae group (e.g. Maize dwarf mosaic virus or Wheat streak mosaic virus) gives rise to what is known as maize lethal necrosis disease (MLND), also referred to as corn lethal necrosis disease (CLND) (Niblett and Caflin, 1978; Uyemoto et al., 1980, 1981; Wangai et al., 2012).
MCMV is transmitted mechanically and spread by several insect vectors including maize thrips (Frankliniella williamsi) (Jiang et al., 1990), maize rootworms (Diabrotica undecimpunctata, Diabrotica longicornis and Diabrotica virgifera), cereal leaf beetles (Oulema melanopus), corn flea beetle (Systena frontalis) and Chaetocnema pulicaria (Nault et al., 1978; Jensen, 1985; Reyes and Castillo, 1988). SCMV is spread by maize aphids (Brandes, 1920). Seed transmission of MCMV has been reported by Jensen et al. (1991).
Infection of maize by any of the viruses alone does not cause MLND. Symptoms of MLND are more severe than the additive symptoms of either MCMV or the potyvirus virus alone. The virus complex causes a severe systemic necrosis which culminates in the death of the plant (Niblett and Caflin, 1978; Uyemoto et al., 1980, 1981; Wangai et al., 2012).
Economic ImpactTop of page
Maize lethal necrosis disease (MLND) is a serious threat to maize production. In Kansas, crop losses due to MLND have been estimated to be 50-90% (Niblett and Claflin, 1978; Uyemoto et al., 1980) depending on the variety of maize and the year. In Peru, losses in floury and sweet maize varieties due to Maize chlorotic mottle virus have been reported to average between 10 and 15%.
In Kenya, in areas where MLND was very serious, farmers experienced extensive or complete crop loss (Wangai et al., 2012). The infected plants are frequently barren; the ears formed are small, deformed and set little or no seeds, drastically reducing the yield. The areas affected constitute major maize production acreage and given the recorded loss of up to 100%, it has become an important food security issue in Kenya.
The impact of the disease can been felt in the whole maize value chain. To help control MLND, the maize seeds have to be dressed with an insecticide in addition to a fungicide seed dressing. Seed producers have incurred an extra cost in the production of seed maize.
Environmental ImpactTop of page
One of the management options for the disease is vector control by the use of insecticides. Maize is planted by a large number of farmers so the increased use of pesticides in the production of maize may have a negative impact on the environment.
Social ImpactTop of page
Maize is grown as both a food crop and a cash crop. Without adequate quantity and quality of the preferred food, there will be increased incidences of theft and general insecurity in the farming community. Lower incomes could increase stress and make school fees unaffordable, preventing children from completing their education.
Prevention and ControlTop of page
Seed Inspectors can check for Maize lethal necrosis disease (MLND) in seed farms. A plant health inspectorate organization can test for Maize chlorotic mottle virus (MCMV) in all seed coming into the country including the material for breeding. Domestic regulation can be put in place to prevent the movement of maize products from affected areas to disease-free regions.
The public can be informed about the disease through press releases, posters, brochures, sensitization workshops and radio programmes. Information on the disease could be passed on to the public during field days and Bazaras in churches. Awareness of the disease will help farmers to take it upon themselves to avoid the movement of diseased plant material from one area to another by destroying affected crops, rouging and practicing general field hygiene.
The best approach for the management of MLND is to employ integrated pest management practices encompassing cultural control such as closed season, crop rotation and crop diversification, vector control using seed treatment followed by foliar sprays, and host-plant resistance.
Cultural Control and Sanitary Measures
Crop rotation can effectively control MCMV (Uyemoto, 1983). Producers are advised to practice crop rotation for at least two seasons with alternative non-cereal crops such as potatoes, sweet potatoes, cassava, beans, bulb onions, spring onions, vegetables and garlic. Planting different crops each season will diversify farm enterprises. Manure and basal/top dressing fertilizers can be applied to boost plant vigour.
It is necessary to use good field sanitation methods, including weed control measures to eliminate alternate hosts for potential vectors (Wangai et al., 2012b). Infected foliar material should be removed from the field to reduce pathogen and vector populations. This material can be fed to livestock, but grain and cobs that are rotten should not be fed to humans or animals. These should be destroyed by burning.
Seed should not be recycled; farmers should plant certified seed only.
To create a break in maize planting seasons, plant maize on the onset of the main rainy season and not during the short rain season. This will reduce the population of vectors.
Before MCMV had spread to other islands in Hawaii, it had been controlled for several years in the island of Kaua’i. (Nelson et al., 2011).
There is need to have regulation by governments to impose quarantine on the movement of maize materials from affected areas within a country. Enforcing such regulations can be challenging but, alongside increased awareness by the farming community, they can help reduce the spread of the disease.
Vector control should target soilborne and early season vectors and combine long residual and fast-acting control agents to achieve faster knockdown and longer protection. Imidacloprid is applied as a seed dressing in combination with foliar sprays. In Hawaii producers of maize seed spray regularly after planting to control insects that spread the virus (Nelson et al., 2011).
Use of tolerant or resistant varieties ultimately would be the most effective means of managing MLND. Superior resistance to MCMV is widely available in tropical maize seed stocks and provides the best control for this disease. According to Nelson et al. (2011), trials performed in Hawaii in 2011 found many tropical inbred lines and varieties to be highly resistant to MCMV. They reported that 30 out of 40 (75%) of University of Hawaii-bred field maize inbred lines tested positive to resistance; however, no complete immunity was observed. Almost all temperate climate inbred lines and hybrids are highly susceptible to the virus (Nelson et al., 2011).
The level of MCMV resistance varies widely among pure lines that have been tested in Hawaii, so it is considered a quantitative trait (Nelson et al., 2011).Preliminary inheritance studies on the inheritance of traits suggest a polygenic control of the disease, with resistance being partially dominant. This encourages the commercial production of hybrids only if both parents are resistant to the pathogen.
In Kenya, varieties are being screened for resistance/tolerance by KARI and CIMMYT in two sites Naivasha and Bomet. Preliminary data from 43 pre-commercial maize hybrids and seven commercial hybrids at Bomet, Chepkitwal and Naivasha, and of 200 elite inbred lines at Naivasha, during one season of screening under natural disease pressure, suggest that MLN-resistant maize germplasm can be identified and developed quickly. KARI, CIMMYT and other partners will reconfirm the potential resistance of pre-commercial hybrids and inbred lines that show the lowest susceptibility to MLN and work urgently to develop resistant varieties (Makumbi and Wangai, 2012). As MLND is due to the co-infection of two viruses, resistance against any one of the viruses would substantially reduce the damage due to the disease. Results of a trial of elite CIMMYT inbred lines under artificial SCMV inoculation showed several highly-resistant lines (Makumbi and Wangai, 2012).
In the long run, deployment of varieties that are resistant to both MCMV and SCMV will be the best means of managing MLND. Through breeding, both conventional and transgenic maize seeds, resistance to MCMV can be incorporated into the susceptible maize varieties within a 4-year period.
ReferencesTop of page
Adams IP, Harju VA, Hodges T, Hany U, Skelton A, Rai S, Deka MK, Smith J, Fox A, Uzayisenga B, Ngaboyisonga C, Uwumukiza B, Rutikanga A, Rutherford M, Ricthis B, Phiri N, Boonham N, 2014. First report of maize lethal necrosis disease in Rwanda. New Disease Reports, 29:22. http://www.ndrs.org.uk/article.php?id=029022
Brandes EW, 1920. Artificial and insect transmission of sugarcane mosaic. Journal of Agricultural Research, 9:131-138.
Carrera-Martinez H, Lozoya-Saldana H, Mendoza-Zamora C, Alvizo-Villasana H, 1989. Enzyme immunosorbent assay (ELISA) in the identification and distribution of maize chlorotic mottle virus (MCMV) in the state of Mexico. (Immunoabsorcion enzimatica (ELISA) en la identificacion y distribucion del virus moteado clorotico del maiz (VMCM) en el estado de Mexico.) Revista Mexicana de Fitopatología, 7:20-25.
Castillo J, Hebert TT, 1974. New virus disease affecting maize in Peru. (Nueva enfermedad virosa afectando al maiz en el Peru.) Fitopatologia, 9:79-84.
Doupnik Jr B, 1979. Status of corn lethal necrosis- 1979 update. In: Proceedings of the 34th Annual Corn and Sorghum Research Conference. Chicago, USA 16-34.
Gordon DT, Bradfute OE, Gingery RE, Nault LR, Uyemoto JK, 1984. Maize chlorotic mottle virus. Description of Plant Viruses, 284 [ed. by Association of Applied Biologists]. http://www.dpvweb.net/dpv/showdpv.php?dpvno=284
Hebert TT, Castillo J, 1973. A new virus disease of maize in Peru. In: 2nd International Congress of Plant Pathology, 72. Minneapolis, USA.
IPPC, 2014. New pest of maize: maize lethal necrosis in Uganda. IPPC Official Pest Report, No. UGA-01/2, No. UGA-01/2. Rome, Italy: FAO. https://www.ippc.int/
IPPC, 2017. Status of Maize lethal necrosis disease (MLND) in kenya IPPC Official Pest Report, No. KEN-02/2. Rome, Italy: FAO. https://www.ippc.int/
Jensen SG, Ooka JJ, Lockhart BE, Lommel SA, Lane LC, Wysong DS, Doupnik Jr B, 1990. Corn lethal necrosis in Hawaii. Phytopathology, 80:1022.
Jiang XQ, Meinke LJ, Wright RJ, Wilkinson DR, Campbell JE, 1992. Maize chlorotic mottle virus in Hawaiian-grown maize: vector relations, host range and associated viruses. Crop Protection, 11(3):248-254.
Jiang XQ, Wilkinson DR, Berry JA, 1990. An outbreak of maize chlorotic mottle virus in Hawaii and possible association with thrips. Phytopathology, 80:1060.
Kusia ES, Subramanian S, Nyasani JO, Khamis F, Villinger J, Ateka EM, Pappu HR, 2015. First report of lethal necrosis disease associated with co-infection of finger millet with Maize chlorotic mottle virus and Sugarcane mosaic virus in Kenya. Plant Disease, 99(6):899-900. http://apsjournals.apsnet.org/loi/pdis
Mahuku G, Wangai A, Sadessa K, Teklewold A, Wegary D, Ayalneh D, Adams I, Smith J, Bottomley E, Bryce S, Braidwood L, Feyissa B, Regassa B, Wanjala B, Kimunye JN, Mugambi C, Monjero K, Prasanna BM, 2015. First report of Maize chlorotic mottle virus and maize lethal necrosis on maize in Ethiopia. Plant Disease, 99(12):1870. http://apsjournals.apsnet.org/loi/pdis
Makumbi D, Wangai A, 2013. Maize lethal necrosis (MLN) disease in Kenya and Tanzania: Facts and actions. CIMMYT- KARI. http://www.cimmyt.org/en/where-we-work/africa/item/maize-lethal-necrosis-mln-disease-in-kenya-and-tanzania-facts-and-actions
Nelson S, Brewbaker J, Hu J, 2011. Maize Chlorotic Mottle Virus. Plant Disease, 79:1-6.
Ooka JJ, Lockhart BE, Zeyen RJ, 1990. New maize virus disease in Hawaii. Phytopathology, 80:892.
Uyemoto JK, Claflin LE, Wilson DL, Raney RJ, 1981. Maize chlorotic mottle and maize dwarf mosaic viruses; effect of single and double inoculations on symptomatology and yield. Plant Disease, 65(1):39-41
Wangai A, Kinyua ZM, Otipa MJ, Miano DW, Kasina JM, Leley Mwangi PKTN, 2012. Maize (Corn) Lethal Necrosis Disease. KARI Information Brochure [ed. by Ministry Of Agriculture].
Wangai AW, Redinbaugh MG, Kinyua ZM, Miano DW, Leley PK, Kasina M, Mahuku G, Scheets K, Jeffers D, 2012. First report of Maize chlorotic mottle virus and maize lethal necrosis in Kenya. Plant Disease, 96(10):1582-1583. http://apsjournals.apsnet.org/loi/pdis
Xie L, Zhang J, Wang Q, Meng C, Hong J, Zhou X, 2011. Characterization of maize chlorotic mottle virus associated with maize lethal necrosis disease in China. Journal of Phytopathology, 159:191-193.
ContributorsTop of page
Original text by:
Hannah Achieng Chore Oduor, Ministry Of Agriculture, PO Box 12168 Nakuru, Kenya.
Distribution MapsTop of page
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