Epidemiology of Southern Corn Leaf Blight in Continuous Corn Culture. Eshetu Bekele, Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton 31793. Donald R. Sumner, Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton 31793. Plant Dis. 67:738-742. Accepted for publication 3 January 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-738.

The influence of cultural practices on the epidemiology of southern corn (Zea mays) leaf blight (SCLB) in continous corn culture was investigated. Field tests showed that tillage practices, row spacing, and fertilizer application methods influenced the development of SCLB in early growth stages of corn but not after tasseling. Tillage systems did not influence the resistance or susceptibility of cultivars to Drechslera maydis race O. In greenhouse studies, no one method of evaluation was adequate to show differences in disease reaction among cultivars. The number of lesions per plant, lesion size, number of conidia per lesion, and number of conidia per square millimeter of lesion were the most useful parameters in determining resistance of cultivars to the SCLB pathogen. Losses may be severe if cultivars susceptible or moderately susceptible to SCLB are grown in continuous corn culture with minimum tillage under overhead irrigation.