Disease Note

Stenocarpella macrospora on Corn in North Carolina. G. A. Payne, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. K. J. Leonard, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. Plant Dis. 69:613. Accepted for publication 7 March 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-613b.

On 16 August 1984, lesions containing Stenocarpella macrospora (Earle) Sutton were found on leaves of corn (Zea mays L.) grown in both conventional and minimum-tilled fields near Marion, North Carolina. In a commercial corn hybrid test, more than 50% of the plants of some hybrids had lesions by 30 August. Lesions were circular to elongate and often up to 25 cm long. Even though leaf lesions were numerous, stalk lodging was not observed in the plots at harvest. The fungus sporulated in culture on autoclaved corn leaves placed on oatmeal agar. Conidia averaged 72 × 11.5 μm, conforming to the published descriptions of S. macrospora. Typical lesions containing pycnidia and cirri developed on leaves of inbred lines B73 and W64A that had been sprayed with a suspension of 6 × 10³ conidia per milliliter and incubated 36 hr in a moist chamber.