Influence of Soil Infestation, Seed Infection, and Seed Treatment on Septoria Nodorum Blotch of Wheat. H. H. Luke, Research Plant Pathologist, USDA, ARS, University of Florida, Plant Pathology Department, Gainesville 32611. R. D. Barnett, Professor of Agronomy, IFAS, Agricultural Research and Education Center, Rt. 3, Box 638, Quincy, FL 32351, and P. L. Pfahler, Professor, IFAS, Agronomy Department, University of Florida, Gainesville 32611. Plant Dis. 69:74-76. Accepted for publication 28 June 1984. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1985. DOI: 10.1094/PD-69-74.

Field experiments were conducted to determine the effects of soil infestation, seed infection, and seed treatment on the development of Septoria nodorum blotch of wheat. In 1981, disease development in plants grown from uninfected seed in infested soil and those grown from infected seed in uninfested soil was similar, but in 1982, disease severity was higher in infested soil plots. Disease in the control plots (uninfested soil/uninfected seed) and seed-treatment plots (uninfested soil/infected seed treated with fungicide) was significantly less than in other treatments. Seed treatment did not reduce the amount of disease on the leaves in infested soil plots. Grain harvested from seed-treatment plots in uninfested soil had lower percentages of seed infection than those harvested from infested soil plots. In 1982, the control and seed-treatment plots had higher grain yields in uninfested soil than the other treatments. In 1983, there were no yield differences among treatments at either location; however, seed treatment increased kernel weight at one location.