Issue link: https://read.dmtmag.com/i/366055
www.goodfruit.com GOOD FRUIT GROWER SEPTEMBER 2014 15 "The truth is, trunk diseases are a major problem in grapes because there's no chemical treatment to cure infected vines," said Úrbez-Torres, adding that there are only prevention treatments available. Once symptoms are observed, the only treatment to contain the disease is to remove the infected arm, cutting about four inches below the canker, and retrain the vine. "You may do everything you should be doing to prevent disease, but if you're next to apples, blueberries, cherries, apricots, almonds, and many other crops, you can get the pathogen just from being there," said Úrbez-Torres. Like a perfect storm, several fac- tors came together in the last decade to heighten the problem of trunk diseases. Úrbez-Torres attributes the rise in disease incidence to a shortage of good quality planting material, high-density plantings, use of susceptible rootstock and cultivars, and loss of effective chemical controls. In British Columbia, vineyards in the rapidly expanding grape industry began experiencing significant yield loss and plant losses in the late 2000s, he said. "Canker diseases are common there in older vineyards, but in recent years, young vine decline has been the most prevalent." He believes part of the problem is infected plant material coming from nurseries. "We don't have a clean plant program in Canada," said Úrbez-Torres, noting that most of their wine grape plant mate- rial comes from outside Canada. "The B.C. wine industry needs a fast, efficient diag- nostic tool to detect pathogens and know if plant material is good to use," he said. Úrbez-Torres and his colleague at the research centre, Dr. Dan O'Gorman, have developed a DNA-based technology that can diag- nose more than 6 0 g r a p e v i n e trunk disease fungal patho- gens within 48 h o u r s . W h e n there was such a high demand for material in C a l i f o r n i a i n the 1990s due to replanting of AXR-1 rootstock, some nurseries didn't cull infe- rior plant mate- rial and sold infected stock, says Dr. Kendra B a u m g a r t n e r , plant patholo- gist for the U.S. D e p a r t m e n t of Agriculture in Davis, California. Many young California vineyards showed symp- toms of poor graft take, stunting, weak growth throughout the vineyard, and mor- tality, which were determined to be caused by a species of the Esca pathogen. "There are a whole group of pathogens, including the trunk diseases Esca and Botryosphaeria dieback, found on nursery stock that are not part of certification pro- grams," she said. Reasons for nonregulation include the lack of reliable detection tools that can be used by nurseries and the ease with which trunk diseases move into the nursery from neighboring vineyards and other crops. Baumgartner has been leading a team of researchers to develop early- detection tools for sampling healthy-looking leaves in the early stage of infection. The team is also testing spore traps in the vineyards— similar to those used to monitor powdery mildew spores—to measure disease risk, learn when to begin preventive practices, and improve timing of such practices. The research project, funded by a grant from the U.S. Department of Agriculture's Specialty Crop Research Initiative, also aims to identify germplasm for resistance and develop more effective preventive practices. Baumgartner and Úrbez-Torres spoke during a session on grapevine trunk diseases at the annual meeting of the Washington Association of Wine Grape Growers. • Black measles, a symptom observed on fruit of Esca- infected vines. "We don't have a clean plant program in Canada." —Dr. José Ramón Úrbez-Torres "We think in terms of quality…" Orchard-Rite® Wind Machines • www.orchard-rite.com W e are developing a 5-acre vineyard on Red Mountain. Last year, we had an October freeze and a hard winter right behind it, causing a fair amount of winter damage. Looking back, we realized a wind machine would have helped us harden off the wood before winter and also give us the protection we need in the spring. We think in terms of quality and this was just one more thing to get us there. We ended up purchasing an Orchard-Rite Machine because the growers that we have the most confidence in recommended Orchard-Rite. We like the Auto Start Preset, and are looking forward to a wireless connection to a weather station, or computer. Orchard-Rite has given us great service even though we only have one wind machine. They are like working with a good neighbor that you trust. John and Peggy Thurtle • Red Mountain, Washington Wind Machine Service For your nearest representative: www.orchard-rite.com 1611 W. Ahtanum Yakima, WA 98903 509-457-9196 Sales: Virgil Anders, ext 114 3766 Iroquois Lane Wenatchee, WA 98801 509-662-2753 Sales: Dana Morgan, ext 215 Dave Harmening, ext 214 Cascade