Practical management of grapevine trunk diseases

Practical strategies for management of the grapevine trunk diseases eutypa and botryosphaeria dieback have been enhanced by new knowledge gained in this project. DNA-based molecular tools were developed to detect inoculum from spore traps, and showed that spore dispersal patterns vary in regions with different climates, highlighting the role of rain and the presence of inoculum over the entire year. Pruning wounds were highly susceptible to infection for the first two weeks, regardless of the pruning time, with susceptibility decreasing thereafter, at various rates, depending on the pathogen.The application of the fungicides Cabrio, Emblem and Folicur to pruning wounds within 6 days of infection, controlled trunk disease pathogens for a total period of up to 3 weeks. In the short-term,remedial surgery was successful for control of botryosphaeria dieback on own-rooted vines, with further work required to improve regeneration of scion material on reworked grafted vines. Cultivarsusceptibility to dieback varies, with potential for tolerance identified in some germplasm, and preliminary evidence of reduced susceptibility in some clones and rootstocks warrants further investigation. Increased water stress generally decreased the susceptibility of canes to colonisation by trunk disease pathogens, suggesting that drought and deficit irrigation practices are not likely to contribute to an increased prevalence of grapevine trunk disease in Australian vineyards. Theseoutcomes provide new information that is leading to adoption of improved strategies for managing trunk diseases, which will increase vineyard longevity in diverse climates of Australia.