Fungi Causing Stalk Rot of Conventional-Tillage and No-Tillage Corn in Delaware. K. J. Byrnes, Graduate Assistant, Department of Plant Science, University of Delaware, Newark 19717-1303. R. B. Carroll, Associate Professor, Department of Plant Science, University of Delaware, Newark 19717-1303. Plant Dis. 70:238-239. Accepted for publication 26 August 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-238.

During 1982 and 1983, 420 rotted cornstalks were collected on the basis of rind discoloration and weakness from commercial farm fields in Delaware. Stalks were collected from both conventionally tilled and nontilled fields. On the basis of stalk symptoms and laboratory isolations, a single major stalk-rot pathogen was identified for each stalk. Representative samples of the most frequently occurring fungi in 1982 were cultured, and spore suspensions were prepared for inoculation tests in 1983. Fusarium spp., Stenocarpella maydis (syn. Diplodia maydis) and Colletotrichum graminicola accounted for 91% of the fungi identified. Fusarium spp. were isolated more frequently from corn in conventionally tilled fields in the sandy soils of southern Delaware, whereas S. maydis was more prevalent in samples collected from no-tillage corn growing in the heavier soils of northern Delaware.