Abstract
A new species of Alternaria causing leaf spots on the rubber tree (Hevea brasiliensis) in Yunnan, China, was isolated, examined, and illustrated. Morphologically, it belongs to the section Porri of Alternaria, which produces relatively large conidia and a simple or branched, filamentous long beak. It is, however, characterized by conidiophores gradually enlarging near the apex into a clavate conidiogenous cell and long ellipsoid to obclavate, smooth-walled conidia with a long filamentous beak. Molecular phylogenetic analyses based on ITS rDNA, GAPDH, and TEF1-alpha sequences demonstrate that the phytopathogen falls in the clade of the section Porri, being most closely related to A. sidae, A. sennae, A. deseriticola, A. cyamopsidis, A. rostellata, A. nitrimali, A. crassa, and A. thunbergiae.