Issue link: https://read.dmtmag.com/i/314286
G rapevine leafroll virus is very costly to growers, studies in major wine-grape-growing regions show. Economists in New York, California, and New Zealand have looked at the costs of leafroll virus in recent years and all found that it significantly reduces yields, said Trent Ball, director of Yakima Valley Community College's agricultural department and partner in Agri-Business Consultants. A New Zealand study estimated yield losses from grapevine leafroll virus as high as 40 percent in Sauvignon Blanc. Cornell University econo- mists found that a 30 percent yield reduction resulted in a loss of $10,000 per acre over a 25-year period and that it was beneficial to replant entire vineyards when infection levels reached 25 percent of the vines. Univer- sity of California researchers estimated that the state's vine certification program for grapevine leafroll-3 virus, which is designed to ensure virus-free planting material, pro- vides a benefit to growers of between 30 and 47 cents per vine for certified vines, totaling between $400 and $615 per acre. Ball is working with Dr. Naidu Rayapati, Washington State University plant pathologist, to estimate the economic losses to Washington growers from grapevine leafroll virus, a project funded by a spe- cialty crop block grant of the Washington State Department of Agriculture. A primary objective of Ball's economic study is to determine how the disease affects growers' pocketbooks and when it is more 36 JUNE 2014 GOOD FRUIT GROWER www.goodfruit.com "When you replant, the cost is huge." —Rick Hamman Leafroll virus is costly Expect to pay $100 per acre to live with the disease or $7,500 per acre to remove and replant an infected vineyard. by Melissa Hansen Grapes