Natural infections of pruning wounds by fungal trunk pathogens in mature grapevines in Catalonia (Northeast Spain)

Abstract

Background and Aims: Information on the natural infection rates of pruned canes caused by fungal trunk pathogens is scarce. This study aimed to determine the pathogenic mycoflora infecting the pruning wounds in two vineyards in Catalonia, Spain, each with a different level of trunk diseases, and in two pruning seasons. Methods and Results: Vines were pruned in each vineyard in mid-autumn leaving four to six buds. Three months later, pathogens were isolated and identified in 250 pruned canes chosen at random in each vineyard. Vines were then definitively pruned to two buds, and sampling for pathogen isolation and identification was repeated 3 months later. The main fungal pathogens identified in this study were Eutypa lata (0-0.4% of isolations), Neofusicoccum parvum (0-1.2%), Botryosphaeria dothidea (0-1.6%), Phomopsis spp. (0-1.6%), Cryptovalsa ampelina (0-3.2%), Phaeomoniella chlamydospora (0-12.0%) and Diplodia seriata (0.4-68.4%). A strong seasonal effect on pathogen infections was detected for most species, with a higher isolation percentage detected after the late pruning as compared with that of the early pruning. Conclusions: Under the environmental conditions and the geographical location of this study, our results showed that the rate of natural infection of pruning wounds was lower following early pruning (autumn) than following late pruning (winter). Significance of the Study: Early pruning could be used in combination with other control measures, such as chemical and biological wound protectants, to reduce the infections caused by the grapevine trunk pathogens during the pruning season in Catalonia, Spain. The infection risk, however, and potential effects of the early pruning on grape production should be considered in other environments before expanding this recommendation to other grapegrowing regions. © 2013 Australian Society of Viticulture and Oenology Inc.