Issue link: http://read.dmtmag.com/i/314286
38 JUNE 2014 GOOD FRUIT GROWER www.goodfruit.com At first, just a few infected vines at a time were removed. Then the number jumped from 76 in 2008 to 182 rogued vines the following year. In 2011, 370 vines were removed. She began mapping locations of removed vines in 2012 and noticed disease progression followed the direction of the wind. WSU's Rayapati found virus in a neighboring Chardonnay block located 120 feet away. "Grape mealybug crawlers in the Chardonnay block were coming out in the spring, and wind was blowing them across to the Cab block," Nye said. Since they began applying Platinum (thiamethoxam) to control grape mealybug and monitoring for the pest, the number of vines that need to be removed has declined significantly. She estimated that living with leaf roll virus adds about $100 per acre to production costs. Costs include insec- ticide sprays for grape mealybug ($25 per acre), virus testing ($25 per acre), and $50 per acre in labor costs for scouting, vine removal, and regrowing vines by layering (burying a shoot from a neighboring vine to regrow in the space of the removed vine). $66,000 tax Rick Hamman, viticulturist for Hogue Ranches, Prosser, likened the economic impact from leafroll virus to an expensive "grape virus tax," a tax that cost Hogue Ranches $66,000 in 2010. He explained that 2010 was a cool year, resulting in late ripening in a Cabernet Sauvignon block. The block struggled to ripen and failed to reach minimum Brix by one degree, resulting in a loss of around $66,000. "That's a big chunk to swallow," he said. "It goes down slowly." Since 2008, Hamman has replaced 112 acres of red and white wine grapes in 11 blocks because of leafroll virus. Seven of the 11 blocks were Cabernet Sauvignon, which totaled 58 acres. Last fall, another 20 acres of Chardonnay were pulled out for replanting due to virus. One of the removed Chardonnay blocks, planted with certified material from Cali- fornia, was in the ground for only three years before showing unusual symptoms that at first were thought to be nutritional. Because the entire vineyard showed uniform symptoms, Hamman believes planting material was infected. Tests were positive for grapevine leafroll virus-3 and Rupestris stem pitting. "The block was Chardonnay Clone 37, and we really wanted that clone. But in 2010, we had a lot of trouble get- ting the fruit ripe," he said, "After 2010, I knew we didn't have a choice except to replant." It takes three years for a new vineyard to begin showing revenue, he noted, and those three nonproducing years were the equivalent of a $119,000 loss of revenue from the 8.5-acre vineyard. Replanting costs "When you replant, the cost is huge," he said. Ham- man estimated it costs more than $7,500 per acre for full vineyard removal and replacement. "These are real costs that we actually paid out, and not just this past year, but for several years." It's a big decision to replant a vineyard, he says. "We take it very seriously because the cost is so huge." Vine removal starts with a three- person crew and a front-end loader to pull out the vines. A very large horse- power tractor must be rented to rip the ground both ways to also remove PVC irrigation pipe. A dumpster must be rented to dispose of pipe and other materials. A root-lifter implement is used to remove as much root material as possible. A burn permit is needed to burn the vine wood and wooden posts. Soil fumigation must be done before replanting. New rows must be marked and vines planted and new irrigation lines installed. In all of this, Hamman has learned that it's critical to scout for the disease and make sure all employees are aware of symptoms. "If you see something, get a lab analysis to learn what you have and quickly remove infected plants." Vineyards with leafroll virus require extra management to ensure that vines are not stressed. Also, he recommends lowering yield targets to three to four tons per acre for red varieties and four to five tons per acre for whites to improve chances of ripening. "Don't propagate if you have any suspicions of virus, and double-check your vine source when using propagative material." The discussions about the economics of grapevine leafroll virus were held at the Washington Association of Wine Grape Growers annual meeting. • 1008 W. Ahtanum Road, #2 Union Gap, WA 98903 509-452-7707 www.cascadeanalytical.com 3019 GS Center Road Wenatchee, WA 98801 509-662-1888 Your Agricultural Water Quality Specialists • Irrigation Water Quality for optimum irrigation system efficiency and delivery • Irrigation Water Microbiology for Good Agricultural Practices (GAP) • Warehouse Process Water Quality for wastewater discharge compliance • Warehouse Water Microbiology for food safety verification program • Drinking Water Potability Tests for worker housing requirement • 800-545-4206 • 360.333.4044 Casey Schoenberger Mount Vernon, WA Dramm Corporation Manitowoc, WI • U.S.A. www.FishFertilizer.com Extremely high levels of available Calcium & Phosphorus Natural Fish Fertilizers for Organic & Sustainable Crop Production BERRIES VINEYARDS ORCHARDS Vineyard removal and replacement costs Actual costs of full removal and replacement of a 20-acre vineyard total more than $7,500 per acre. Task Cost per acre Demolition (trellis, vine, root burning, and dumpster) $500 Ground prep (ripping, PVC pipe removal, disking, fumigation) 942 Irrigation system install MRGPYHIW½PXVEXMSRW]WXIQ Trellis wire, end posts, line posts, ERHERGLSVWJSVRI[\JXWTEGMRK Virus-free vines ZMRIWEGVI$IEGL Protective vine tubes, bamboo, tape for staking vines 300 0EFSV Year 2 growing and training costs [IIHMRKWTVE]MRKXVEMRMRK Total 7,554 SOURCE: Rick Hamman, Hogue Ranches