1. Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, U.S.A.
2. Department of Plant Pathology, College of Agricultural and Environmental Science, University of Georgia, Tifton, GA 31793, U.S.A.
3. Department of Entomology and Plant Pathology, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC 27695-7630, U.S.A.