New Races of Hemileia vastatrix Detected in Peruvian Coffee Fields

Coffee leaf rust (CLR), a fungal disease caused by Hemileia vastatrix, represents Peru’s most significant threat to coffee production. The CLR epidemic (2012–2013) led Peru to implement an emergency plan under which coffee plantations underwent renewal using rust-resistant varieties derived from a Timor hybrid (HDT; Coffea arabica × canephora hybrid) like Catimors. Nevertheless, new pathogenic rust races capable of infecting these varieties have been recorded. Eighteen rust samples from coffee genotypes, such as Caturra, Typica, and Catimor, were collected in various Peruvian regions and sent to CIFC/ISA/UL (Centro de Investigação das Ferrugens do Cafeeiro/Instituto Superior de Agronomia/Universidade de Lisboa) in Portugal for race characterization. Assessing the virulence spectra of rust samples on a set of 27 coffee differentials resulted in the identification of 5 known and 2 new races. This study emphasizes the significance of conducting surveys on the diversity of H. vastatrix races in Peru for effective disease management. Moreover, Catimor lines, widely cultivated in coffee-growing countries, are susceptible to the 2 new races and to races XXXIV and XXXV identified in this study. Thus, coffee farmers need to know the resistance spectrum of new varieties before introducing them to CLR-affected regions.