VIEW ARTICLE

Ecology and Epidemiology

Influence of Inoculum From Buried and Surface Corn Residues on The Incidence of Corn Anthracnose. P. E. Lipps, Associate professor, Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691; Phytopathology 75:1212-1216. Accepted for publication 17 June 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/Phyto-75-1212.

Field experiments were conducted to determine the relative importance of buried and surface corn residues as sources of inoculum for anthracnose of corn. Naturally-infected corn residues or oat-kernel cultures of Colletotrichum graminicola were used to simulate inoculum sources. When oat-kernel inoculum was planted with seeds of different hybrids (C123 x FRB73, A632 x H95, B73 x Mo17, B73 x OH545, and FRB73 x FR16; not all were used each year during 2 yr of testing at two locations each year) no difference (P = 0.05) in the incidence of anthracnose stalk rot was detected between inoculated and uninoculated treatments, except for the very susceptible hybrid C123 x FRB73. During the second year, removal of leaves above the ears 2 wk after pollination to induce photosynthetic stress, did not influence the incidence of anthracnose stalk rot. Also, burying corn residues below seeds of A632 x H95 did not affect the incidence of anthracnose stalk rot. However, the incidence of anthracnose leaf blight and stalk rot was greater (P = 0.05) in treatments with surface residues than in treatments without residues. In an additional test, the incidence of anthracnose leaf blight and stalk rot was negatively correlated (P = 0.01) with distance from the residue area. These results indicate that surface corn residues, not buried residues, are an important source of inoculum for corn anthracnose.