1. Dep. of Crop Sciences Univ. of Illinois at Urbana‐Champaign Urbana IL 61801 USA
2. Dep. of Plant Pathology and Microbiology Iowa State Univ. Ames IA 50011 USA
3. Bioagricultural Sciences and Pest Management Colorado State Univ. Fort Collins CO 80525 USA
4. Smithsonian Tropical Research Institute Apartado 0843–03092, Balboa, Ancon, Republic of Panamaì