Botryosphaeria species associated with diseases of grapevines in Portugal

Although Botryosphaeria species are known to cause cankers and dieback in many different woody hosts, their importance in grapevines has been largely ignored. Indeed, they are more often regarded as saprophytes or weak pathogens. In the work presented here the species of Botryosphaeria associated with wood and trunk diseases of grapevines in Portugal were determined. Three species, namely, B. obtusa, B. parva, and B. lutea, were regularly associated with trunk dieback, wood necrosis, brown wood streaking, cane bleaching or incomplete grafts. Botryosphaeria parva was the most common and widely distributed species. Botryosphaeria dothidea and B. stevensii were less common; the former was found on bleached canes and on necrotic tissues at the graft union while the latter was isolated from necrotic buds, and occasionally from brown streaks in the wood. These data indicate that B. parva is associated with many of the symptoms normally linked with infection by other fungi in the grapevine decline syndrome. To stimulate further research on this genus, descriptions of the species associated with grapevines and an identification key are provided.