The Identification of a Limited Number of Vegetative Compatibility Groups within Isolates of Sclerotinia homoeocarpa Infecting Poa spp. and Agrostis palustris from Temperate Climates

Sclerotinia homoeocarpa is responsible for causing significant damage on a wide variety of different grass species. Because it is an asexual fungus, the study of its population structure can be difficult. Previous research has determined that S. homoeocapra has anywhere from three to 20 vegetative compatibility groups (VCGs) within localized geographic ranges in the United States. However, a survey of a large geographic area has yet to be undertaken. The present study examined 25 isolates of S. homoeocarpa from the United Kingdom, Rhode Island, Massachusetts, Connecticut, Ohio, Illinois and Oregon. Among the 25 isolates, eight VCGs were identified. Other researchers have reported that there are seven VCGs in temperate North America on amenity turfgrasses. It is still unclear how this relates to the pathogen’s VCG diversity in subtropical and tropical climates