Published online by Cambridge University Press: 21 May 2001
Morphological characters and genetic markers from 35 single-ascospore isolates of a Venturia sp. collected from Populus tremula were analysed. The morphological data were compared with the literature, and genetic markers were amplified for comparison with isolates of V. populina, V. macularis and V. ditricha. According to ascospore morphology the fungus resembled V. populina, but the morphology of the conidia was closer to Pollaccia radiosa (the anamorph of V. macularis). Analysis of 49 RAMS markers, variation within the internal transcribed spacer (ITS) sequence of the ribosomal gene cluster and a single marker locus derived from RAMS fingerprint suggested that the Venturia is a previously undescribed species.