1. Wageningen University and Research Center, 6700 AA Wageningen, The Netherlands;, ,
2. United States Department of Agriculture, Agricultural Research Service, Salinas, California 93905;
3. Virology Laboratory, International Center for Tropical Agriculture (CIAT) and Consultative Group on International Agricultural Research (CGIAR) Research Program on Roots, Tubers and Bananas (RTB), Cali, Colombia;
4. Plant Protection Program, Fera, Sand Hutton, York YO41 1LZ, United Kingdom;
5. Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853;