Seventeen pathogenic strains of Pseudomonas cichorii were isolated from leaf samples of coffee (Coffea arabica) collected from nurseries in eight municipalities of Puerto Rico. Two different inoculation methods were evaluated under in vitro conditions: inoculation of plant-attached old and young leaves grown under greenhouse conditions, and plant-detached young coffee leaves grown under field conditions. Pseudomonas cichorii was more virulent in older leaves, thus indicating that resistance mechanisms differ according to leaf age. Both inoculation methods were reliable in identifying resistant genotypes. Three commercial varieties of coffee (Borbón, Pacas and Caturra) were susceptible to bacterial leaf blight, whereas coffee species Coffea liberica var. Excelsa and Coffea canephora var. Robusta were resistant.Diecisiete cepas patogénicas de Pseudomonas cichorii se aislaron de muestras de hojas de cafetos, Coffea arabica, procedentes de viveros en ocho municipios de Puerto Rico. Se evaluaron dos métodos de inoculación in vitro: hojas adultas y jóvenes en plantas creciendo bajo condiciones de invernadero, y hojas tiernas separadas de plantas creciendo bajo condiciones de campo. Pseudomonas cichorii fue más virulento en las hojas adultas, indicando diferentes mecanismos de resistencia de acuerdo a la edad de la hoja. Ambos métodos fueron confiables para identificar resistencia a Pseudomonas cichorii. Tres variedades comerciales de café (Borbón, Pacas y Caturra) fueron susceptibles a Pseudomonas cichorii mientras que las especies Coffea liberica var. Excelsa y Coffea canephora var. Robusta fueron resistentes.