Good Fruit Grower

March 1

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Page 20 of 47 Good Fruit Grower MARCH 1, 2016 21 However, F 2/5 still causes necrosis of the roots, so researchers worked to see if they could develop a derivative of F 2/5 that was necrosis-free. They knocked out the gene tied to causing the necrosis and found that it still maintains the ability to knock down the tumorigenic strain of A. vitis. They are working to develop the practice for commercial use. "This is something that could be quite useful, both for treating grafts and treat- ing dormant cuttings before rooting, two sites that could be infected with crown gall," he said. Advice for growers In the meantime, growers should take steps to try to prevent crown gall in vineyards, Burr said. These include planting certified clean material and varieties that are more tolerant of the disease — all Vitis vinifera are susceptible, but some more so than others — in sites with good air circulation and well drained soil. Two sites in the National Clean Plant Network provide the best options for plant materials for Washington growers: Clean Plant Center Northwest and the Russell Ranch in California, which is at lower risk for the disease than other out- of-state centers but is not risk free, said Michelle Moyer, Washington State Uni- versity plant pathologist. That's because plants that are produced in a warm location could be infected and not show symptoms until they are exposed to a freeze after being planted in Washington. Growers should reduce likelihood of cold damage by hilling around the trunks and train with multiple trunks, Moyer said. "The galls don't appear until after bloom — after you've pruned — so keep some of those suckers as an insurance policy if you've had a cold snap," she said. Burr added that growers should man- age vine growth with minimal amounts of water, while keeping vines in good shape heading into winter to protect against freeze damage as much as possible. Kevin Judkins of Inland Desert Nurs- ery made a similar point. Some growers are pushing the limit on what they can grow where — such as Cabernet Sauvi- gnon in too cold an area. They need to be more selective about pairing growing sites and varieties and follow good man- agement practices to prevent cold injury, he said. • "If you can plant a vineyard with clean plants, you certainly are not going to eliminate the presence of crown gall forever, but if you can get a healthy vineyard started, you're way ahead." —Thomas Burr Krista Peach Snow Fox Peach Krista Peach Snow Fox Peach Snow Lady Peach Rich Snow Peach Summer Gold Peach Honey Spring Nectarine Honey Spring Nectarine Order by May 1 st for a Pre-Bud Discount! (209) 874-1821 Fax 874-1920 Toll Free 800-654-5854 Designed for Orchards & Vineyards CALIFORNIA 509-952-9488 PASCO 509-544-6678 WALLA WALLA 509-525-4550 UNION GAP 509-248-8411 GEORGE 509-785-2595 MATTAWA 509-932-4001 SUNNYSIDE 509-839-2066 See Your Nearest Blueline Equipment Dealer Today . . . Featuring the BLUELINE ELECTROSTATIC SPRAYER Newest Technology • Electrostatic System - Reduces Drift, Improves Coverage • Adjustable Pitch Fan - Reduce Overspray • 2 Speed Gearbox with Neutral • Fresh Water Hand Washing and Rinsing Tank • Galvanized Steel Frame • Electric Controls • Efficient Jet Ignition • 400 Gallon Poly Tank • Blueline Quality Available For Rental or Purchase

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