Harpophora maydis (late wilt of maize)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- Risk of Introduction
- Habitat List
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- List of Symptoms/Signs
- Biology and Ecology
- Means of Movement and Dispersal
- Seedborne Aspects
- Pathway Causes
- Pathway Vectors
- Plant Trade
- Impact Summary
- Economic Impact
- Risk and Impact Factors
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Gaps in Knowledge/Research Needs
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Harpophora maydis (Samra, Sabet & Hing.) W. Gams 2000
Preferred Common Name
- late wilt of maize
Other Scientific Names
- Cephalosporium maydis Samra, Sabet & Hing. 1963
Summary of InvasivenessTop of page
H. maydis is a soilborne and apparently seedborne fungus, related to the root-infecting species in the genus Gaeumannomyces. It is known from only a few scattered countries, where it can cause significant losses, but may have been unobserved in others in which the primary host, maize [Zea mays], is grown. This fungus was reported recently from Portugal and Spain (Molinero-Ruiz et al., 2010). No dispersal by fungal propagules has been demonstrated, so that, other than in soil, its likely means of spread over borders would be in seed. Importation of the fungus with seed is considered to be the source in Hungary (Pécsi and Németh, 1998). Although research has been carried out on chemical and biological control methods, the development and use of resistant varieties is the most practical means of control. Regulation and testing of imported seed should prevent transport of the pathogen to new regions.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Fungi
- Phylum: Ascomycota
- Subphylum: Pezizomycotina
- Class: Sordariomycetes
- Subclass: Sordariomycetidae
- Family: Magnaporthaceae
- Genus: Harpophora
- Species: Harpophora maydis
Notes on Taxonomy and NomenclatureTop of page
This fungus was initially described as Cephalosporium maydis, based on its production of “heads” of hyaline, non-septate conidia from simple phialides (Samra et al., 1963). Gams (2000) observed that it is similar to anamorphs of species of Gaeumannomyces and Magnaporthe in conidiogenous cell morphology and in that its colonies are fast-growing, thin and pigmented in culture. He transferred it to the new genus Harpophora comprised of those anamorphs. The divergent collarettes that Gams observed on the phialides are not apparent in the earliest photographs of the species (Samra et al., 1963). Molecular studies indicate that H. maydis is closely related to species of Gaeumannomyces, a genus in the Magnaporthaceae, but support it as a distinct species (Ward and Bateman, 1999; Saleh and Leslie, 2004).
DescriptionTop of page
Culture on PDA (potato dextrose agar) white to pale-grey, becoming dark-grey to black. Mycelium appressed, felty, margin “rhizoidal”, the outermost hyphae branching to resemble roots; hyphal “ropes” curving clockwise. Hyphae hyaline, septate. Conidiophores 60-250 µm or longer, mostly branched; conidia formed in phialides at apices, collecting in “heads”. Conidia straight, mostly one-celled, hyaline, oblong, 3.5-14.0 x 3.5 µm. Sclerotia-like bodies, composed of several thick-walled pigmented cells, formed in old cultures.
DistributionTop of page
This pathogen has been known to occur in Egypt (Samra et al., 1963) and India (Payak et al., 1970) for some decades. It is more recently reported from Portugal and Spain (Molinero-Ruiz et al., 2010), Hungary (Pécsi and Németh, 1998) and may be present in Kenya (Ward and Bateman, 1999). These widely scattered locations suggest its probable transmission by seed, but also a failure to distinguish its symptoms from those of other diseases or stresses (Freeman and Ward, 2004). Although the known host, maize [Zea mays], originated in Central America (Maiti and Wesche-Ebeling, 1998), the relatively recent appearance of this disease in the widely-grown crop may indicate a different source of the fungus.
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.Last updated: 10 Jan 2020
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Egypt||Present||SAMRA et al. (1963); Mouchacca (1994)||As Cephalosporium maydis|
|Kenya||Present||Introduced||Invasive||Freeman and Ward (2004)||unconfirmed|
|India||Present||PAYAK et al. (1970)|
|-Andhra Pradesh||Present||PAYAK et al. (1970)|
|-Rajasthan||Present||Singh and Siradhana (1987); Singh and Siradhana (1987a); Singh and Siradhana (1989)|
|Hungary||Present||Introduced||Invasive||CABI (Undated)||Original citation: Pécsi and Németh (1998)|
IntroductionsTop of page
Risk of IntroductionTop of page
The risk for introduction of H. maydis to new areas lies in its capacity to be seedborne; the risk of establishment in new areas lies in the widespread cultivation of maize [Zea mays] as a food crop and in the ability of the fungus to survive in plant debris and possibly in the soil.
Habitat ListTop of page
|Terrestrial – Managed||Cultivated / agricultural land||Present, no further details||Harmful (pest or invasive)|
Hosts/Species AffectedTop of page
Zea mays is the major crop so far known to be damaged, but the fungus may have other hosts, particularly if it originates from Egypt or India rather than with Z. mays from the western hemisphere. Lupinus termis [Lupinus albus var. albus], a cultivated forage legume, has been reported as a host in Egypt (Sahab et al., 1986).
Host Plants and Other Plants AffectedTop of page
Growth StagesTop of page Flowering stage, Fruiting stage, Pre-emergence, Seedling stage, Vegetative growing stage
SymptomsTop of page
Leaves wilt moderately rapidly beginning in the tasseling (flowering) period or later. Progressing upward from the lower part of the plant, leaves become dry and dull green, rolling inward and eventually losing colour. Vascular bundles in the stalk turn reddish-brown and then internodes also become discoloured. Lower portions of the stalk are dry, shrunken, and hollow (Samra et al., 1962). Some plants develop yellowish to purple or dark-brown streaks on the lower stem (Payak et al., 1970; El-Shafey and Claflin, 1999). Rotting of roots and lower internodes may involve secondary organisms (Sabet et al., 1961; Samra et al., 1962).
List of Symptoms/SignsTop of page
|Inflorescence / wilt|
|Leaves / abnormal colours|
|Leaves / leaves rolled or folded|
|Leaves / wilting|
|Leaves / yellowed or dead|
|Roots / soft rot of cortex|
|Seeds / rot|
|Stems / discoloration of bark|
|Stems / internal discoloration|
|Stems / rot|
|Whole plant / early senescence|
|Whole plant / wilt|
Biology and EcologyTop of page
Soilborne or seedborne H. maydis infects the roots of young plants or the seedling mesocotyl, invades the vessels, and grows or is translocated from the roots up the stalk and into the ear stalks and grain (Samra et al., 1963; Sabet et al., 1970b). Initial superficial growth on the roots consists of short, brown, thick-walled swollen cells (Sabet et al., 1970b). In India, maximum disease occurred at a constant 24°C or when the temperature varied naturally between 20 and 32°C. Less disease was obtained at a constant temperature of 36°C (Singh and Siradhana, 1987). These parameters correspond approximately to earlier observations of an optimum temperature of 30°C for growth on PDA (potato dextrose agar) and yeast-extract-glucose agar, with the maximum for growth at 36°C; no growth occurred at 8 or 38°C (Samra et al., 1963).
The fungus was found to remain viable and virulent in/on seeds in the laboratory for up to 10 months. Mycelium added to soil survived 3 months if the soil was sterilized, but only half as long if it was untreated (Singh and Siradhana, 1988). Other studies found H. maydis to have low competitive saprophytic ability in soil and to be inhibited by the growth of soil microorganisms (Sabet et al., 1970a). In infected stems kept inside at 20-35°C, the fungus survived and retained pathogenicity for up to 24 months. In the field, stem pieces on the surface of the soil retained the pathogen for 12 months, but it could not be recovered after 10 months from pieces buried at 10 cm (Singh and Siradhana, 1987b). The researchers suggested that survival with seed would be longer in cooler climates.
Physiology and Phenology
This pathogen was distinguished initially by its rapid growth in culture (Samra et al., 1963). A slow-growing variant was reported by Payak et al. (1970) in India, but because conidia and conidiophores were not observed, its identification cannot be assured.
Zeller et al. (2000) and Saleh et al. (2003) found four distinct genetic lineages among Egyptian isolates. No gene flow between them was apparent, suggesting clonality of generation and the absence of sexual reproduction (Saleh et al., 2003).
Virulence and competitive ability are not the same in H. maydis, varying independently among the four lineages of the pathogen in Egypt (Zeller et al., 2002). The most virulent lineage was least competitive in mixed inoculum and one of the less virulent was present in 70% of infections.
The rot of the base of the affected stem and the associated roots is partly due to secondary organisms. Sabet et al. (1961) identified the fungi Rhizoctonia bataticola, Fusarium moniliforme and other Fusarium species, as well as some bacteria, from stalks primarily affected by late wilt. Fusarium graminearum and F. moniliforme are stalk rot-causing fungi that have been frequently found together with H. maydis in seed samples of maize [Zea mays] in Egypt (Mohamed et al., 1967).
As a “temporary root-surface inhabitant” that does not penetrate beyond the epidermis, H. maydis can reduce root infection and disease in cotton [Gossypium spp.] caused by Fusarium oxysporumf. vasinfectum in Egypt (Sabet et al., 1966). The protective effect was greater when H. maydis was added to the soil of potted plants before the cotton pathogen.
ClimateTop of page
|Am - Tropical monsoon climate||Preferred||Tropical monsoon climate ( < 60mm precipitation driest month but > (100 - [total annual precipitation(mm}/25]))|
|BS - Steppe climate||Preferred||> 430mm and < 860mm annual precipitation|
|BW - Desert climate||Preferred||< 430mm annual precipitation|
|Cs - Warm temperate climate with dry summer||Tolerated||Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers|
|Df - Continental climate, wet all year||Tolerated||Continental climate, wet all year (Warm average temp. > 10°C, coldest month < 0°C, wet all year)|
Means of Movement and DispersalTop of page
Conidia are the only spore form produced, thus they could be the means of dispersal, but this has not been demonstrated to occur in nature. The spores have been observed in xylem vessels (Samra et al., 1962). Sclerotia are a means of survival in soil and are dispersed with soil (Dawood et al., 1980).
The presence of the fungus in and/or on seed has been established (see Seedborne Aspects). Importation of infected seed is considered to be the cause of the pathogen’s appearance in Hungary (Pécsi and Német, 1998). Movement of soil on machinery or tools could carry the fungus locally.
Seedborne AspectsTop of page
H. maydis was detected in 39 out of 42 seed samples in Egypt (Mohamed et al., 1967). Seed infection was induced in plants inoculated at planting time (Samra et al., 1963). In Hungary, Michail et al. (1999) detected H. maydis in a higher percentage of white maize [Zea mays] seeds (1-9%) than in yellow cultivars (1-3%). The fungus was detected in different ear parts, i.e. ear branch, cob, seeds, ear husks, and silk, of naturally-infected maize cultivars. It was manifested most in the branch and less in the cob, seeds, husks and silk, although no part was infected at a level greater than 10%.The fungus was detected in the embryo, the endosperm and seed coat of seed in 12 of the 13 samples tested, with the exception of that of cv. Amon (Michail et al., 1999).
Pathway CausesTop of page
Pathway VectorsTop of page
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Flowers/Inflorescences/Cones/Calyx||hyphae||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Roots||hyphae||Yes||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Seedlings/Micropropagated plants||hyphae||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Stems (above ground)/Shoots/Trunks/Branches||hyphae||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|True seeds (inc. grain)||hyphae||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Plant parts not known to carry the pest in trade/transport|
|Fruits (inc. pods)|
|Growing medium accompanying plants|
Impact SummaryTop of page
Economic ImpactTop of page
This is a late-season disease of widespread incidence and severity in Egypt, with 100% infection reported in some fields (Samra et al., 1962; Galal et al., 1979). Yield losses up to 40% in susceptible cultivars are reported (El-Shafey and Claflin, 1999).
The fungus is one of the most important pathogens of maize [Zea mays] in some parts of India (Payak et al., 1970; Singh and Siradhana, 1988), causing yield losses of up to 100% (Satyanarayana, 1995). It does not occur in the USA, but is considered to be a potentially important pathogen (Warren, 1983).
Risk and Impact FactorsTop of page Invasiveness
- Invasive in its native range
- Proved invasive outside its native range
- Fast growing
- Has propagules that can remain viable for more than one year
- Reproduces asexually
- Has high genetic variability
- Host damage
- Negatively impacts agriculture
- Negatively impacts livelihoods
- Difficult to identify/detect as a commodity contaminant
- Difficult to identify/detect in the field
DiagnosisTop of page
Saleh and Leslie (2004) found a unique 300 bp sequence of rDNA in all strains of H. maydis tested indicating that the PCR primer pair for that sequence could be used in a specific identification test. Molecular methods can also be used to distinguish the species from Gaeumannomyces and Phialophora pathogens of maize [Zea mays] stems (Ward and Bateman, 1999). Sequences of the ITS and other regions of nuclear DNA are available in GenBank for comparison (NCBI, 2010).
Detection and InspectionTop of page
The symptoms of wilt, external and internal discolouration of stems, and stalk rot are not particularly distinctive and may be obscured due to drought, over-irrigation or other pathogens.
Similarities to Other Species/ConditionsTop of page
H. maydis lacks a known teleomorph, but is similar to the Harpophora anamorph of Gaeumannomyces species in culture (Saleh et al., 2003). It can be distinguished from other pathogenic Acremonium species due to its fast growth in culture on complex media, minimal growth on Czapek’s agar (a defined medium), and eventual dark pigmentation (Samra et al., 1963). The conidiophores can be quite long and the conidia are generally larger than those of other pathogenic Acremonium species (Samra et al., 1963). The divergent collarettes on the phialides (Gams, 2000) also separate it from Acremonium and other anamorphic fungi pathogenic to maize [Zea mays].
Although drought and other stalk- or root-rotting pathogens can cause wilt, the late appearance of the symptoms under conditions of adequate soil moisture are characteristic of this disease.
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
As the fungus is apparently seedborne, seed testing and certification could help to prevent its introduction into new areas or countries. Maize [Zea mays] seed from countries where the pathogen is present should be tested most carefully if it is used.
Cultural Control and Sanitary Measures
Crop rotation with rice [Oryza sativa] provides some control, but the fungus may survive several years in soil in Egypt (El-Shafey et al., 1988; El-Shafey and Claflin, 1999). In India, it remained viable in stem pieces on the surface of the soil for 12 months, but could not be recovered after 10 months from pieces buried at 10 cm (Singh and Siradhana, 1988). High soil moisture favours disease, but saturated soil reduces it (El-Shafey and Claflin, 1999).
A number of organisms have shown promise as control agents. Six isolates of actinomycetes (Streptomyces graminofaciens, Streptomycesgibsonii, Streptomyces lydicus, Streptomyces nogalater, Streptomyces rochei, Streptomyces anulatus) and five isolates of yeasts (Candida maltosa, Candida glabrata, Candida slooffii, Rhodotorula rubra, Trichosporon cutaneum)from the rhizosphere of maize in Egypt were antagonistic to H. maydisin vitro, and, when applied to the seed, significantly reduced the incidence of late wilt of maize planted in H. maydis-infested sterilized soil in the greenhouse (El-Mehalawy et al., 2004). The fungus, Trichurus spiralis was also found to inhibit the growth of H. maydis in liquid culture, on solid medium, and in soil in pots (Abdel-Hamid et al., 1981). Suspensions of the antagonistic bacterium, Bacillus subtilis, or its culture filtrate, reduced infection when added to infested soil in pots either at the time of sowing or after sowing (Sellam et al., 1978).
Benomyl controlled the pathogen in pots and in culture, but was not effective when applied to soil (Sabet et al., 1972). In India, significant reduction of late wilt incidence was obtained with 0.1% Benlate [benomyl], 0.1% Bavistan [carbendazim], or 0.2% Bayleton [triadimefon] applied to the soil as a drench after stem-inoculation of sixty-day-old plants in pots (Singh and Siradhana, 1989).
The use of resistant varieties is considered to be the best, most practical method of control (Samra et al., 1963; El-Shafey et al., 1988). Resistance to stalk rot caused by H. maydis and other fungi was observed in different maize varieties, inbred lines and hybrids, by Mohamed et al. (1966). The Egyptian resistant hybrid DC-19 was introduced by Labib et al. (1975). Hybrid varieties have been reported to be more susceptible than open-pollinated ones (Sabet et al., 1961). In India, high levels of resistance were detected in lines X102, CM111, and (CM104 × Warangal Local)-1-1-1 (Satyanarayana, 1995). Resistance is polygenic, quantitatively inherited, and due to additive gene effects (Shehata, 1976; Galal et al., 1979; El-Shafey et al., 1988).
Observing four lineages with different regional distributions among Egyptian isolates of the pathogen, Saleh et al. (2003) suggested that resistant lines could be deployed according to the lineages present in a region. Resistance would need to be tested with all four lineages, individually as well as in the usual combination, because virulence and competitiveness were not linked among the isolates (Zeller et al., 2002).
Gaps in Knowledge/Research NeedsTop of page
Possible alternative hosts that could enhance the pathogen’s survival and spread should be tested. A fast and reliable identification protocol for use on infected tissue should be established. Cultural practices that could minimize disease or contain the spread of the fungus need to be identified. Sources of genetic resistance in maize [Zea mays] must be sought.
ReferencesTop of page
El-Mehalawy AA; Hassanein NM; Khater HM; Karam El Din EA; Youssef YA, 2004. Influence of maize root colonization by the rhizosphere actinomycetes and yeast fungi on plant growth and on the biological control of late wilt disease. International Journal of Agriculture and Biology, 6(4):599-605.
El-Shafey HA; El-Shorbagy FA; Khalil II; El-Assiuty EM, 1988. Additional sources of resistance to the late-wilt disease of maize caused by Cephalosporium maydis. Agricultural Research Review (Egypt), 66:221-230.
Labib HA; Salem A; Abd El Rahim ME; Abd El Fattah A, 1975. DC 19, a new maize hybrid seed resistant to late-wilt disease caused by Cephalosporium maydis. Agricultural Research Review (Egypt), 53(8):1-4.
Mohamed HA; Ashour WE; Sirry AR; Fathi SM, 1967. Fungi carried by corn seed and their importance in causing corn diseases in the United Arab Republic. Plant Disease Reporter, 51:53-56.
Molinero-Ruiz ML; Melero-Vara JM; Mateos A, 2010. Cephalosporium maydis, the cause of late wilt in maize, a pathogen new to Portugal and Spain. Plant Disease, 94(3):379. http://apsjournals.apsnet.org/loi/pdis
NCBI, 2010. Entrez cross-database search engine. Entrez cross-database search engine. Bethesda, Maryland, USA: National Center for Biotechnology Information, U.S. National Library of Medicine, unpaginated. http://www.ncbi.nlm.nih.gov/sites/gquery
Payak MM; Lal S; Lilaramani J; Renfro BL, 1970. Cephalosporium maydis - a new threat to maize in India. Indian Phytopathol., 23:562-569.
PTcsi S; NTmeth L, 1998. Appearance of Cephalosporium maydis Samra Sabet and Hingorani in Hungary. Mededelingen - Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen, Universiteit Gent, 63(3a):873-877; 23 ref.
Samra AS; Sabet KA; Hingorani MK, 1963. Late wilt disease of maize caused by Cephalosporium maydis. Phytopathology, 53:402-406.
Satyanarayana E; Begum H, 1996. Relative efficacy of fungicides (seed dressers) and irrigation schedule for the control of late wilt in maize. Current Research University of Agricultural Sciences Bangalore, 25(4):59-60.
Singh SD; Siradhana BS, 1987. Influence of some environmental condition on the development of late wilt of maize induced by Cephalosporium maydis. Indian Journal of Mycology and Plant Pathology, 17:1-5.
Zeller KA; Ismael ASM; El-Assiuty EM; Fahmy ZM; Bekheet FM; Leslie JF, 2002. Relative competitiveness and virulence of four clonal lineages of Cephalosporium maydis from Egypt toward greenhouse-grown maize. Plant Disease, 86(4):373-378.
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
Freeman J, Ward E, 2004. Gaeumannomyces graminis, the take-all fungus and its relatives. Molecular Plant Pathology. 5 (4), 235-252. http://www.blackwell-synergy.com/rd.asp?code=MPP & goto=journal DOI:10.1111/j.1364-3703.2004.00226.x
Singh S D, Siradhana B S, 1987a. Influence of some environmental condition on the development of late wilt of maize induced by Cephalosporium maydis. Indian Journal of Mycology and Plant Pathology. 1-5.
ContributorsTop of page
02/04/10 Original text by:
Distribution MapsTop of page
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