Phyllachora maydis Maubl. 1904.
There are no nomenclatural or taxonomic synonyms in our records. The type of P. maydis was collected from Zea mays leaves in Mexico. The genus Phyllachora (lectotype Phyllachora graminis (Pers.:Fr.) Fuckel) (Hawksworth et al., 1995) is associated with the anamorph genus Linochora (Orton 1944).
Geographic Distribution and Plant Hosts
The only host recorded for P. maydis is Zea mays L. (Poaceae). P. maydis is the primary causal agent of tar spot of corn, but it often occurs in association with other fungi including Monographella maydis E. Müll. & Samuels 1984 (anamorph Microdochium sp.) (Mueller & Samuels 1984) and Coniothyrium phyllachorae Maubl. 1904 (Carson 1999). P. maydis can be common on cultivated corn under appropriate environmental conditions. During an outbreak in Puerto Rico in 1915, P. maydis was found in nearly every field examined (Dalbey 1917). Germination of ascospores and formation of appressoria are maximal from 10° to 20° C, and decrease above 25° C, which appears to explain its predominance at high elevations with a cool, humid climate (Dittrich et al. 1991). In susceptible corn plants, the entire leaf area can be blighted, but resistant lines have been developed (Ceballos & Deutsch 1992). Predominant modes of pathogen transmission are unknown (McGee 1990).
P. maydis has been recorded in Mexico, Cuba, Puerto Rico, the Virgin Islands, the Dominican Republic, Panama, Nicaragua, El Salvador, Venezuela, Costa Rica, Colombia, Guatemala, Honduras, and Brazil. In the secondary literature, reports of P. maydis in France (e.g., Stevenson 1975, McGee 1990) appear to refer to Maublanc’s description of collections from Mexico, published in Bull. Soc. Mycol. France 20:72, 1904. Stevenson (1975) includes an ambiguous reference to the presence of P. maydis in the continental US (as ‘Puerto Rico—Continental US), but this could not be substantiated in any of the references he listed. Initial reports of Phyllachora graminis in Puerto Rico were later discovered to refer to P. maydis (Stevenson 1975). In our database, there are currently no reports of P. graminis on Zea mays, so these misidentifications appear to have been corrected. Phyllachora maydis has been intercepted in New York NY (on shipments from Guatemala), Miami FL (on shipments from Guatemala), and San Diego CA (on shipments from Mexico). Excluding interceptions, there are no substantiated reports of P. maydis in the continental United States.
Phyllachora maydis Maubl. 1904 (Ascomycetes, Phyllachorales)
Distribution: North America, South America.
Disease Note: Tar spot.
Host: Zea mays (Poaceae).
Parbery, D.G. 1967. Studies on graminicolous species of Phyllachora Nke. in Fckl. V. A taxonomic monograph. Austral. J. Bot. 15: 271-375.
Updated on Oct 07, 2009
Carson, M.L. 1999. in D.G. White, ed., Compendium of Corn Diseases, 3rd Ed., APS Press, St. Paul MN USA, p. 25.
Ceballos, H. & Deutsch, J.A. 1992. Inheritance of resistance to tar spot complex in maize. Phytopathology 82:505-512.
Dalbrey, N. A. 1917. Phyllachora as the cause of a disease of corn, and a general consideration of the genus Phyllachora. Trans. Ill. Acad. Sci. 10:230-248.
Dittrich, U., Hock, J., and Kranz, J. 1991. Germination of Phyllachora maydis ascospores and conidia of Monographella maydis. Crypt. Bot. 2/3, 214-218.
Hawksworth, D.L., Kirk, P.M., Sutton, B.C., and Pegler, D.N. 1995. Ainsworth & Bisby's dictionary of the fungi. 8th Ed. CAB International.
McGee, D. 1990. A Reference Source for Seed Technologists. APS Press, St. Paul MN, 150 pp.
Mueller, E., and Samuels, G.J. 1984. Monographella maydis sp. nov. and its connection to the tar-spot disease of Zea mays. Nova Hedwigia 40:113-120.
Orton, C.R. 1944. Graminicolous species of Phyllachora in North America. Mycologia 36:18-53.
Parbery, D.G. 1967. Studies on graminicolous species of Phyllachora Nke. in Fckl. V. A taxonomic monograph. Austral. J. Bot. 15:271-375.
Stevenson, J. A. 1975. The fungi of Puerto Rico and the American Virgin Islands. Contr. of Reed Herbarium 23:200.
Report written by Erica Cline, 4/22/2005.
Suggested citation: Cline, E. Phyllachora maydis. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved October 9, 2015, from /sbmlweb/OnlineResources/FungiOnline.cfm .
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