Corn, Pennsylvania's major grain crop, is extremely important to the state's agricultural economy. Depending on growing season and location, diseases of corn have a major impact on yields. Corn stalk rot is the most serious disease of corn in Pennsylvania on an annual basis. Northern leaf blight and gray leaf spot are the two most important foliar diseases, and both occur annually at various locations in the state. Most of my research focuses on these diseases.

My overall goal is to reduce corn losses by improving disease resistance through plant-breeding procedures designed to accumulate resistance genes in the crop. A major portion of this research is conducted in the field in cooperation with faculty in the Department of Agronomy. The type of resistance in which I am primarily interested is inherited as a quantitative genetic trait. It often is not an "all or nothing" type of resistance. In other words, most of the "resistant" genotypes develop some level of disease, but compared with other, more susceptible genotypes, the disease that does develop is less severe, and yield losses are lower. Specific projects include (1) defining the genetics of resistance in the host, (2) defining the genetics of virulence in the pathogen, (3) conducting related epidemiological studies to quantify the value of this resistance, and (4) reducing the impact of disease.

Elwinger, G. F., M. W. Johnson, R. R. Hill, Jr., and J. E. Ayers. 1990." Inheritance of resistance to gray leaf spot of corn." Crop Science 30:350­358.

Heineman, P. H., D. D. Calvin, J. M. Carson, J. E. Ayers, V. Esh, R. Hartzler, J. G. W. Kelley, J. McClure, G. Roth, and J. Tollefson. 1992. "MAIZE: A decision support system program for management of field corn." Journal of Applied Engineering 8:407­414.

Graham, M. J., J. A. Hawk, R. B. Carroll, J. E. Ayers, K. R. Lamkey, and A. R. Hallauer. 1993. "Evaluation of Iowa stiff stalk synthetic for resistance to gray leaf spot." Plant Disease 77:382­385.