Irrigation Management and Root and Stalk Rot of Corn. Donald R. Sumner, Department of Plant Pathology, University of Georgia, Coastal Plain Station, Tifton 31793. James E. Hook, Department of Agronomy, University of Georgia, Coastal Plain Station, Tifton 31793. Plant Dis. 69:239-243. Accepted for publication 10 September 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-239.

Irrigation treatments did not influence populations of Pythium spp., Rhizoctonia solani, or binucleate Rhizoctonia-like fungi or root disease severity at pollination. Root disease severity at pollination was greater following peanut in Tifton loamy sand than in Bonifay sand, but there were very few root lesions following soybean in either soil. Rainfall and irrigation over years and soil type accounted for 30% of the variation in stalk rot severity. Stalk rot increased with decreasing rainfall during the vegetative period and with increased rainfall during the reproductive period. In 2 yr of experiments, there was significantly more stalk rot following wheat-soybean or peanut on Bonifay sand (62%) than on Tifton loamy sand (38%). In 1983, there was a significant positive linear relationship between stalk rot and yield on Bonifay sand (R² = 0.48) but not on Tifton loamy sand.