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70 P R A C T I C A L W I N E R Y & V I N E YA R D October 2015 S M A R T V I T I C U L T U R E Strategy 3: As above, and begin program of water-shoot generation and training to replace all trunks within one or two years. Strategy 4: For all vines, winter-prune very hard, remove all trunks in spring, train suckers for replacement trunks, or, remove all vines and replant. Notes • Basal suckers may be encouraged by a hard pruning in winter followed by late spring trunk removal. They may also be encouraged by careful bark removal on part of the basal trunk. Suckers may need to be trained in transparent plastic tubes to protect them from herbicides, and gen- erally they need to be staked or tied to the trunk as they can break off easily in the first year. Plastic tubes can provide train- ing support. Suckers will usually grow very strongly, even if the parent vine is not immediately removed. Often a reason- able bud number can be retained at winter pruning at the end of the first growing season, to produce some yield in the fol- lowing growing season. This is facilitated by training two new trunks per vine. • When removing trunks, the cut should be below the stain by 4 to 8 inches, and the final cut should be made at a 45° angle, facing south for the Northern Hemisphere. This assists drainage of sap and drying the cut surface. • Treat all wounds with a protectant fungicide, especially large cuts and espe- cially if this is being done in the dormant season. • Remove all vine parts from vineyard and burn as soon as possible. • Encourage two suckers—one on each side of the vine—in line with the vine row. If small, spur-prune them in winter. Two suckers can be used to form two trunks, a helpful insurance against new infections, or an extra in case of damage. • It is imperative to protect new trunks and cordons from infection. Protect- ing a pruning wound with a fungicide spray, paste or paint/fungicide mixture is strongly suggested. Fungicide sprays only provide protection for about two weeks. Avoid making pruning cuts in wet weather. Conclusion Adoption of this protocol will allow vine- yards to recoup some losses from the rav- ages of trunk disease, assuming you time it before significant yield losses already have occurred. The sooner the protocol is adopted, the less loss of yield there will be, and the infection will spread more slowly. The aim was to develop a systematic method for growers to address trunk dis- ease issues in commercial vineyards, so they might maintain vineyard productiv- ity while at the same time containing spread of the diseases. Experience in many countries shows that the sooner that trunk renewal begins, the more successful it will be to control spread of disease and yield loss. PWV Acknowledgements The author gratefully acknowledges valu- able input from Kendra Baumgartner, Doug Gubler and Rhonda Smith (U.S. Department of Agriculture Agricultural Research Service, and University of California). Their California experience has much improved the column, as has the editor's input. Editor's note: For more information, go to practicalwinery.com. Back issues: "Research update: Grapevine trunk dis- eases in California," Janu- ary/February 2005. Dr. Richard Smart is a quali- fied and experienced viticultur- ist. Contact him at vinedoctor@ smartvit.com.au. Keep your business going strong with new and improved Western Square barrel racks. westernsquare.com n 209.944.0921 WESTERN SQUARE I N D U S T R I E S When was the last time you replaced your old barrel racks? Are you confident your barrel racks are still safe and secure? For over 30 years, we at Western Square have been in the business of helping you build yours. Our barrel racks are: • Affordable and won't break your budget • Able to accomodate over 7,000 lbs. of materials— ensuring the safety of you and your employees. Holding your business together, one rack at a time.