Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/30/2002
Publication Date: 11/30/2002
Citation: ABBAS, H.K., SCIUMBATO, G., KEELING, B. 2002. FIRST REPORT OF FALSE SMUT OF CORN (ZEA MAYS) IN THE MISSISSIPPI DELTA. PLANT DISEASE. 86:1179. Interpretive Summary: False Smut is a fungus, Usdilaginoidea virens, that causes disease on corn and rice. During 2000, this disease was observed on corn in the Mississippi Delta. It caused sclerotia (black growth) on the tassels but little damage to the plants. This disease is of interest because it is the first report on corn in the Mississippi Delta, but fortunately, it apparently does not cause decreased yields.
Technical Abstract: False smut, caused by the fungus Usdilaginoidea virens, occurs on rice, corn, and other Gramineae, but is of little economic importance on these crops. The false or green smut of corn seems to resemble most closely the false smut of rice. On corn, the disease will likely be less injurious than on rice. During surveys in 2000 at Mississippi State University, Delta Experiment Station, Stoneville, MS, thirty-two commercial and inbred corn hybrids out of 1280 (2.5%) had false smut on the tassel. The number of plants infected with false smut ranged from 5 to 15% based on sampling 20 corn plants from a single 4.9 m row plot. In 2001 and 2002, the disease was not observed. Galls (sclerotia), similar to ergot which replaces the flowers on the tassels occurred on infected plants. Disease severity ranged from only a few flowers infected up to 50% infected flowers per inbred. Mature sclerotia were spherical, 6-17 mm in diameter, olive-green to black, and velvety with white interiors, which resemble smut sori. The fungus could not be isolated on potato dextrose agar (PDA). Only the tassels were infected, which resulted in little damage to the plant, except a partial decrease in pollen production. The disease has been reported to infect other parts of the plant. Disease incidence was more prevalent in 2000 because of hot, wet weather immediately after the crop was planted. The observation of the disease in one growing season suggests the pathogen may be common in the Mississippi Delta and the disease may occur with favorable environmental conditions and susceptible corn hybrids.