Archivio Journal of Plant Pathology

Abstract:

In European populations of the grapevine powdery mildew fungus Erysiphe necator (formerly Uncinula necator), two genetic groups (A and B or I and III) have been described, but the hypothesized association of them with distinct subpopulations showing different overwintering forms, i.e. quiescent mycelium in buds and cleistothecia, is still debated. A group-specific SCAR primer pair (UnE-UnF) was used for studying extensively the distribution of the two groups of isolates in populations of the pathogen present in 32 vineyards located in southern Italy. In 27 vineyards all the sampled isolates belonged to one of the two groups, while in 5 vineyards both groups were detected. In these cases, group A was generally prevailing until June, while group B prevailed from July to October, with only one exception. Observations carried out on representative isolates of the two groups showed no differences in colony growth and germination of conidia at different temperatures and intergroup fertility in sexual crosses.