BIOLOGY AND EPIDEMIOLOGY OF PLANT PATHOGENIC AGENTS INFLUENCING HOST PLANT RESISTANCE, PATHOGEN VIRULENCE AND DISEASE MANAGEMENT.

The Integrated Aerobiology Modeling System (IAMS), developed by Isard et al (2005), has been employed during the past 6 years to forecast the seasonal geographic spread of soybean rust (SBR) in North America. Estimates of savings to U.S. soybean growers that have resulted from activities associated with the soybean rust component of the PIPE vary greatly (e.g., Roberts et al 2006, Dorrance et al. 2007) and include a conservative calculation of approximately $200 million per year (Giesler and Hershman 2007). In anticipation of the possible incursion of new wheat stem rust races (Ug99) into North America and recent concern over the regional spread of southern corn rust, the IAMS has been expanded to forecast the aerial transport of these diseases in North America (Russo and Isard 2011, USDA 2011). Information on aphid transmission of soybean dwarf virus and adaptation to soybean crops will be useful in determining the risk of SbDV populations moving from widespread indigenous clover hosts into soybean crops on an epidemic scale. This information will be useful for disease risk analysis and development of epidemiological models of virus spread. Integration of host defense response in plants together with the use of environmentally friendly compounds represents the most sustainable method for controlling plant diseases rather than relying totally on fungicides. Information about the host defense response in perennial ryegrass would be useful in developing an integrated disease management strategy using novel compounds as well as compounds that are already known to elicit immune response in other plants. The epidemiological study of gray leaf spot of perennial ryegrass turf implies a deeper understanding of the relationship of environmental factors with gray leaf spot epidemics (Uddin et al. 2003). The results of the research will provide insights into disease forecasting model and integration of novel cultural practices, which will reduce the heavy reliance of fungicide application of gray leaf spot. Molecular tools are not currently widely used in the turfgrass industry. Therefore, the implementation of a molecular technique to accurately quantify dollar spot DNA and predict disease epidemics will provide turfgrass managers with a new resource to combat dollar spot, as more money is spent annually for the control of this disease on high input turfgrass than any other disease (Viji et al., 2004; Vargas, 1994). Additionally, use of molecular tools would aid in the practice of integrated pest management and to reduce the use of unnecessary fungicide applications.