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Physoderma maydis (brown spot of corn )
Physoderma maydis
brown spot of corn
Cladochytrium maydis, Physoderma zeae-maydis
Africa: Cameroon, Congo, Ghana, Kenya, Libya, Malawi, Mozambique, Nigeria, Sierra Leone, Tanzania, Togo, Uganda, Zambia, Zimbabwe; Asia: Bangladesh, Bhutan, Cambodia, China, Georgia, India, Indonesia, Japan, Laos, Nepal, Pakistan, Philippines, Thailand; Europe: Russia; North America: Costa Rica, Cuba, El Salvarod, Guatemala, Mexico, Panama, USA; Oceania: Australia; South America: Argentina, Brazil, Colombia, Venezuela.
AL, AR, CA, DE, FL, GA, HI, IL, IN, IA, KS, KY, LA, MD, MN, MS, MO, NE, NJ, NC, OH, OK, SC, SD, TN, TX, VA, WV
2025-12-29
fungus
Korea
Main: corn
PHYDMA
Physoderma maydis is a chytrid fungus that causes Physoderma brown spot and node rot of maize. The disease is usually of minor importance in the United States but may occur locally under warm, wet conditions, particularly in reduced-tillage systems with infected corn residue. Symptoms include small yellow spots on leaves, sheaths, and stalks that darken to brown lesions; infections at stalk nodes may weaken tissues and cause stalk breakage. The pathogen is soilborne, surviving in crop residue and soil; infection occurs via water-mediated zoospores under warm, wet conditions. Seed transmission has not been demonstrated.
Crops
Zea mays
corn
No
PHYDMA-2, PHYDMA-3, CABI CPC, McGEE, PHYDMA-4, PHYDMA-5, PHYDMA-6
Physoderma maydis causes Physoderma brown spot and node rot of corn and is primarily a soil- and residue-borne pathogen. The pathogen survives as thick-walled sporangia in soil and debris and infects young corn tissues via water-dispersed zoospores when free moisture, light, and temperatures of approximately 23–30 °C are present. Although Broyles (1962) suggested the pathogen may occasionally overwinter in corn seed, this report provided no documented evidence of seed infection or transmission, and seed is not considered a pathway.
No
-
Look for small yellow spots on maize leaves, sheaths, and stalks that darken to brown, often form bands and coalesce into blotches with dusty brown sporangial pustules, sometimes leading to stalk breakage at the nodes.
biological, cultural
Resistant varieties are available. Remove crop debris. Mycorrhizal studies are being conducted as a bioprotectant
CABI CPC, PHYDMA-5
2025-12-30 11:18:01
PHYDMA-2
Broyles JW, 1959. Incidence of brown spot of corn in Mississippi in 1957 and estimations of its effect on yield. Plant Disease Reporter, 43:18-21.
PHYDMA-3
Varshney, JL 1988. Pathogenic fungi recorded in maize crop raised from exotic germplasm. Indian Phytopathol. 41:242-244.
CABI CPC
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
McGEE
McGee, DC. 1988, Maize Diseases; A reference source for Seed Technoligists. American Phytopathological Society, St. Paul, MN USA
PHYDMA-4
Munkvold, G. P., & White, D. G. (2016). Back Matter. In Compendium of Corn Diseases, Fourth Edition (pp. 147-165). The American Phytopathological Society.
PHYDMA-5
Adamou, S., Heu, A., Mboussi, S. B., Kone Nsangou, A. N., Sinama, P., Sesseumaga, E., ... & Ambang, Z. (2023). Effect of Arbuscular Mycorrhizal Fungi (AMF) on development of brown spot disease of corn (Zea mays L.) due to Physoderma maydis in Far North Cameroon. MYCOPATH, 20(1).
PHYDMA-6
Robertson, A. E., Jesse, L., Munkvold, G., Rojas, E. S., Mueller, D. S., 2015. Physoderma brown spot and stalk rot of corn caused by Physoderma maydis in Iowa.Plant Health Progress, No.MayPHP-BR
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