English: tar spot; tar spot of maize; Spanish: mancha de asfalto; mancha negra; mancha negra del maiz; French: tache noire du mais. El “complejo mancha de asfalto” del maíz, su distribución geográfica, requisitos Etiología y manejo de la mancha de asfalto (Phyllachora maydis Maubl.). mancha de asfalto del maiz . Malaguti, G. Subero, L.J.. Access the full text: NOT AVAILABLE. Lookup the document at: google-logo. mancha de asfalto del.
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More significant damage to leaves and yield is caused by the fungus Monographella maydis whose infec More significant damage to leaves xsfalto yield is caused by the fungus Monographella maydis whose infection follows that of the tar-spot fungus, at least where studied in Mexico Hock et al. The source of initial inoculum for both fungi is not determined.
The disease they cause occurs in the cooler and higher elevations of Mexico, and Central and South America, and the West Indies, so their asvalto to spread over land through other climatic zones may be limited. Not known to be seedborne or to infect other species, P. It is the only species reported on Zea and is restricted to Zea Parbery, ; Like other species of Phyllachorait has a pycnidial anamorph in the genus Linochora Een, ; Muller and Samuels, Characters mnacha the anamorph are useful in distinguishing species within the genus Parbery safalto Langdon, Clypeus amphigenous, developing in epidermis, generally circular, 0.
Ascospores uniseriate in ascus, hyaline, aseptate, broadly ellipsoid, 5. Conidiomata pycnidial, subepidermal beneath clypeus, often in younger lesions. Conidiophores branched at two or three levels, branches tapering, x 1. For additional descriptions see DalbyOrtonParberyand Liu Known primarily from the cooler and higher elevations Malaguti and Subero, ; Bajet et al. Adfalto lists it as present in Brazil, but Hock et al. 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. To cause the serious damage that occurs in the native range, the two fungi would need to be introduced awfalto in order to threaten the crop, unless M. Rainfall was not a significant factor in disease progress and severity.
In Mexico, disease is most severe at elevations of m and in the cooler months from November to April, at lower altitudes Bajet et al. Initial symptoms are small, yellow-brown spots on either side of the leaf. The raised glossy black clypeus covering the ascomata, surrounded by a narrow chlorotic border, develops in the spot. Spots are circular, oval, sometimes angular or irregular, and may coalesce to form stripes up to 10 mm long Liu, Some spots enlarge around the ascomata, manxha an initially water-soaked area becoming necrotic, to form circular-oval brown lesions mm diameter with a dark outer edge Bajet et al.
These larger lesions coalesce after days; areas between spots become water-soaked and dry out. When conditions favour disease, leaves may be fully dead in days. The fungus spreads from the lowest leaves to upper leaves, leaf sheathes and the husks of developing ears Bajet et al. Affected ears have reduced weight and loose kernels, and kernels at the ear tip may germinate prematurely CIMMYT, Ascospores of Phyllachora spp. Most of the spores trapped were in clusters of three or four; the fungus was able to spread up to 75 m from infected plants.
In eastern lowland Mexico, tar spot begins to appear approximately 2 weeks before flowering and reaches a maximum severity approximately 6 weeks later Hock et al. Infection may also occur at the 8 to 10 leaf stage Hock et al. The clypeus stroma of Phyllachora species grows separately in the epidermis on either side of the leaf and is not an extension of the perithecia Parbery, b.
The pycnidia of the Linachora asexual state appear early in infection Parbery, ; Hock et al. Spores of the anamorphs of Phyllachora species tested did not germinate in water on slides or on host plants, and probably serve as spermatia in mating Parbery and Langdon, Phyllachora species are generally obligate parasites, and cannot be cultured on the usual laboratory media Parbery, b.
The apparent necrotrophic activity of P. The anamorphic form of Monographella maydis usually grows in the necrotic areas around the ascomata Muller and Samuels, ; Bajet et al. In lowland eastern Mexico, when only P. Leaf inoculations with M. This other pathogen may be present as an endophyte Muller and Samuels, ; Bajet et al. Symptoms caused by M. The temperature range for optimal germination of M.
mancha de asfalto del maiz 
The higher optimum for the second pathogen may be a factor in its later appearance, following P. Conidia in dried manchs in the laboratory or in leaves on the ground from August manfha December in lowland Mexico, began losing viability after 1 month, although survival outdoors was better Hock et al.
Another member of the fungus complex associated with tar spot is Coniothyrium phyllachoraea pycnidial fungus that is considered to be a hyperparasite on Phyllachora. Its incidence on P.
Tar spot lesions containing C. Windborne ascospores of P.
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Plants located up to feet away from a source of inoculum were infected in Puerto Rico Liu, Parbery a suggested rain splash as a dispersing agent for Phyllachora on grasses in Australia. Rainfall was not a major factor in severity of the disease in lowland eastern Mexico Hock asfato al. Other than maize, a source of initial inoculum for a new crop is unknown Hock et al. If maize [ Zea mays ] is not in continuous cultivation locally and the fungus does not survive well in crop debris, then volunteer plants or wild species of Zea or other grasses are the likely sources of re.
The disease was not found on grasses or on wild Zea teosinte asfalro Mexico Hock et al. In eastern lowland Mexico, the disease is observed on maize throughout the year Bajet et al. Tropical and subtropical maize cropping patterns may allow the pathogen to persist and multiply.
Arrasa la “Mancha de Asfalto” con siembra de maíz | El Veraz
This has not been reported, but the natural means of mancua may not be sufficient to explain spread between environmentally favourable areas of maize cultivation at higher elevations in South America or to islands in the Caribbean. Transport of ears in the husk or of items made with leaves or husks are possible means of introduction. No species of Phyllachora are reported as seedborne Richardson, They were unable to isolate M.
Greater losses were suggested to be possible where environmental conditions are more favourable or cultivars grown are more susceptible.
Other types of losses may include reductions in quality of grain, plants used asfato feed, or husks used for food wrapping Bajet et al. Lower leaves should enn examined for small, raised, glossy, dark, circular, or oval to irregular, spots, or for brown lesions, often with a dark border, having a dark ascomata at the centres CIMMYT, Orton distinguished P.
According to his key, other North American species that are similar, occur on grasses in genera such as AndropogonAnthephoraBoutelouaPanicumPaspalumSpartina and Stenotaphrum.
COMPARTE Y COMENTA
According to the only monograph of the genus Parbery, ;the morphologically similar species of Phyllachora cause tar spot asfslto BoutetouaCynodonand Chloris. Species reported on Sorghum were distinguished by the shape of the ascus from Phyllachora oxysporaand the greater manchha of ascospores from both P. Among other leaf spots on maize [ Zea mays ], tar spot is unique in the dark glossy clypeus, 0. Measures to reduce the initial inoculum for a new crop would depend on the source of that inoculum and cultivation practices.
Where maize [ Zea mays ] is grown continuously in the maancha, efforts at sanitation are not likely to be effective. Elsewhere, removal of volunteer plants or wild maize relatives may be appropriate. Reduction in size of P. Naiz one or two treatments and mancozeb applied every 10 days were found to be the most effective fungicides in field plot tests in Mexico Bajet et al. The means of persistence and sources of initial inoculum other than maize [ Zea mays ] need to be determined.
In addition, important questions concerned with whether Monographella maydis or a related species, an endophyte, or epiphyte of maize elsewhere, introduced with P. In addition, it should be determined how susceptible to either pathogen maize cultivars grown elsewhere in environments favourable for tar spot are.
Lista de Hongos Fitopatogenos de Cuba [English title not available]. Editorial Cientifico-Tecnica, pp. Control of tar spot of maize and its effect on yield. International Journal of Pest Management, 40 2: Baker Red; Dale WT, Fungi of Trinidad and Tobago. Diseases of minor importance or limited occurrence. Compendium of Corn Diseases [ed. American Phytopathological Society, Ceballos H; Deutsch JA, Inheritance of resistance to tar spot complex in maize.
A guide for field identification. International Maize and Wheat Improvement Center, pp. Systematic Mycology and Asaflto Laboratory. Phyllachora as the cause of a disease of corn, and a general consideration of the genus Phyllachora. Transactions of the Illinois State Academy of Science, Germination of Phyllachora maydis ascospores and conidia of Monographella maydis.
Cryptogamic Botany, macha Requisitos ambientales para el desarrollo del “complejo mancha de asfalto” que ataca astalto mais en Mexico. Sequential development of pathogens in the maize tarspot disease se. El “complejo mancha de asfalto” de maiz, su distribucion geografica, requisition ambientales e importancia economica en Mexico.