Overwintering and Spore Release of Cercospora zeae-maydis in Corn Debris in North Carolina. Gary A. Payne, Assistant Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27650. J. Keith Waldron, Research Technician, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Plant Dis. 67:87-89. Accepted for publication 27 May 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-87.

Cercospora zeae-maydis survived from November 1979 until May 1980 in corn (Zea mays) debris in fields located in the piedmont region (Raleigh) and mountains (Fletcher) of North Carolina. The fungus survived at Raleigh when positioned 100 cm above the soil surface, on the soil surface, or buried 15 cm below the surface. At Fletcher, the fungus did not survive beyond January in leaf tissue buried 15 cm below the surface. Conidia of C. zeae-maydis were collected in the air above corn debris as early as 19 June 1979. The concentration of airborne conidia was greatest during the week of 27 September–2 October, when the corn kernels were in dough to late dent stage of development. Lesions with C. zeae-maydis did not appear until 19 July (corn in late whorl stage), and rapid disease progression did not occur until September when corn kernels were in milk stage. C. zeae-maydis can overwinter in corn debris and produce conidia early in the season. Failure of the disease to develop early in the season may be related to unfavorable microclimate within the corn canopy.