1. The Virology Laboratory; International Potato Center (CIP); Av. La Molina 1895 Lima 12 Lima Peru
2. Facultad de Agronomía; Programa de Fitopatología; Universidad Nacional Agraria La Molina; Lima 12 Peru
3. Department of Agriculture; College of Agricultural and Environmental Sciences; Makerere University; P.O. BOX 7062 Kampala Uganda