Influence of Tillage and Crop Rotation on Yield, Stalk Rot, and Recovery of Fusarium and Trichoderma spp. from Corn. P. E. Lipps, Associate Professor, Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691. I. W. Deep, Professor, Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691. Plant Dis. 75:828-833. Accepted for publication 16 February 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0828.

An experiment was established in 1985 on a Hoytville silty clay loam soil in northwest Ohio to determine the effect of tillage (fall plowing vs. no tillage) and crop rotation (continuous corn [Zea mays] vs. corn-soybean [Glycine max]) on corn production. In 1987 and 1988, data were taken on grain yield, incidence of stalk rot, and recovery of Fusarium and Trichoderma spp. from stalk, crown, and subcrown mesocotyl tissue. During 1987 and 1988, precipitation from April through September was only 69 and 40%, respectively, of the long-time average. In both years, yield was significantly higher in corn-soybean rotation than in continuous corn. Incidence of stalk rot was not influenced by crop rotation in either year, but there was significantly higher stalk rot in fall-plowed than in no-tillage treatments in both years (1987 [P = 0.06] and 1988 [P = 0.05]). Severe stalk rot in 1987 (87.5% mean of all treatments) was caused primarily by F. graminearum. In 1988, stalk rot was much less severe (19.4% mean of all treatments) and was caused by F. moniliforme. These differences appeared to be related to different rainfall patterns. Levels of stalk-rotting Fusarium spp. in both years remained low in the subcrown mesocotyl but increased in crown and stalk tissues as the season progressed. T. pseudokoningii and T. hamatum were prevalent in subcrown mesocotyls, crowns, and stalks in both years at constant levels throughout the sampling period.