Canker and dieback on Platanus x acerifolia caused by Diaporthe scabra

Cankers and dieback on London plane caused by Diaporthe scabra have been observed in urban plantings in Catania, Italy. Symptoms were delayed spring flush, trunk cankers, small chlorotic leaves associated with dead terminal or lateral branches and an early defoliation. Isolations from infected wood on PDA led to the isolation of the anamorph Phomopsis scabra with alpha-conidia production. The infected wood placed in a moist chamber developed pycnidia with alpha and beta conidia and perithecia of the teleomorph D. scabra. Sequence analysis of the internal transcribed spacers ITS1 and ITS2, the ribosomal intragenic spacer beta-tubulin 1 and beta-tubulin 2 genes, congruently indicated that the D. scabra isolate is phylogenetically related to two strains of D. helianthi isolated in Italy from sunflower and to strains of D. eres. Inoculations on young plants of London plane growing in pots confirmed the pathogenicity of the isolated fungus. To our knowledge, this is the first report of the disease in Italy.