Field studies will be conducted to determine how host population size, host spatial pattern, host diversity, and size of initial disease foci affect the spread of disease. Wheat stripe rust will be studied in isolated, artificially inoculated field plots in which host variables and initial focus size will be manipulated experimentally. Continental-wide data from the newly introduced soybean rust disease will be evaluated, and intensive, finer-scaled sampling of soybean rust will be done in 256 commercial soybean fields in Iowa. A range of mathematical approaches will be used to help understand how host variables and size of initial disease foci affect disease spread at different spatial scales.
While many epidemics occur at national and international scales, understanding such large-scale processes remains a challenge. The goal of this project is to develop general principles, applicable to many diseases, that will enable prediction of disease spread at a wide range of spatial scales. Such predictions are crucial to developing strategies to avoid and respond to epidemics of plants, animals, and humans. The project also will provide specific information with regards to wheat stripe rust and soybean rust, both of which are currently of great economic importance in the U.S.
