Pruning Cut Position Affects the Susceptibility of Grapevine Pruning Wounds to Eutypa lata and Natural Dieback

Background and Aims Grapevine pruning wounds are major infection courts for trunk disease pathogens such as Eutypa lata , the causal agent of the globally devastating disease Eutypa dieback. Recently popularised pruning techniques claim to influence grapevine pathology and physiology. This study investigated whether pruning cut position influences susceptibility of wounds to E. lata and the extent of wood staining associated with natural dieback. Methods and Results Three trials were conducted on Shiraz vineyards in South Australia to compare (i) spur‐pruning with and without retention of long stubs and (ii) cane‐pruning using crown or flush cuts. Wounds were either inoculated with E. lata ascospores or left as noninoculated controls to evaluate natural infection. Retaining stubs or base buds significantly reduced staining and recovery of E. lata compared with no‐stub or flush cuts. Crown cuts, where buds were retained, produced smaller wounds and more noncount shoots than flush cuts, where buds were removed. Conclusions and Significance of the Study These findings suggest that pruning practices that preserve internodes or base buds can limit infection by E. lata and natural dieback, complementing existing trunk disease management strategies. This is the first study to scientifically confirm the effect of pruning cut position on infection by a grapevine trunk disease pathogen. Further research using a range of cultivars, climates and pathogens is warranted to confirm these results.