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Disease Note. Gray Leaf Spot Epiphytotic in Ohio Corn. P. E. Lipps, Department of Plant Pathology, Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691. Plant Dis. 71:281. Accepted for publication 1 December 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0281F. Gray leaf spot, caused by Cereospora zeae-maydis Tehon & Daniels
(I), has been reported infrequently in Ohio corn (Zea mays L.) but
caused severe damage for the first time during the 1986 growing season.
The disease was most severe in the east central part of the state in
Coshocton, Holmes, Knox, Tuscarawas, and southern Wayne counties.
Approximately 8,000 ha were affected, but disease severity varied
greatly among fields and ranged from a few lesions per plant to near
100% leaf coverage by 6 wk after tasseling. Although precise yield loss
estimates could not be made, farmers with severely affected fields
reported harvesting less than one-half the expected yield. Reduced-tillage,
continuous-corn fields were most severely affected, especially
those located in river bottoms. Precipitation for the latter half of July,
August, and mid-September was 7.06 cm (8.12 cm below normal), but
heavy dews and fog were common. Although differences in disease
severity were detected among commercial hybrids in fields and
demonstration plots, none appeared to have sufficient resistance to
protect against yield loss. |