Good Fruit Grower

August 2016

Issue link: https://read.dmtmag.com/i/705612

Contents of this Issue

Navigation

Page 45 of 63

30 AUGUST 2016 Good Fruit Grower www.goodfruit.com P lanting with certifi ed, "clean" plant material is the fi rst line of defense against grapevine viruses. But research funded by the Washington wine industry shows that growers need more than just "clean" for vineyard health, longevity and profi tability. Washington wine industry's rapid expansion during the past 15 years, combined with a shortage of certifi ed grape plant material and limited diagnostic technology, has resulted in disease creep throughout the state. Grapevine leafroll disease, the most prevalent of grapevine viruses in the world, is also the most prevalent viral disease in Washington. Of nearly 1,500 samples collected throughout the state during the last two years from red and white wine grape varieties, around 70 percent tested positive for grapevine leafroll associated virus 3. (See "Grape viruses in Washington," May 14, 2014, Good Fruit Grower). Close to 6 percent were positive for grapevine red blotch associated virus, 8 percent had a combination of leafroll and red blotch viruses and 16 percent were negative for leafroll and red blotch, but positive for other viruses. Samples were taken based on visual virus symptoms for red varieties, but random samples were taken for whites because whites don't show symptoms. Grapevine viral diseases are especially challenging. Visual symptoms that show in the leaves can be con- fused with other factors (mechanical injury, nutritional imbalance, heat or environment stress), and different vectors are involved in virus spread. Mealybug insects and scale are known vectors of leafroll disease, while the three cornered alfalfa treehopper was recently identifi ed GOOD TO KNOW Certifi ed plants are only the fi rst step Growers need to monitor for virus in early years of a "clean" vineyard. by Melissa Hansen Healthcare WASHINGTON FARM BUREAU Paying too much for health coverage? Call the Washington Farm Bureau today to learn how we can lower your costs. Affordable group health coverage options for you, your family, and your employees Medical I Dental I Vision I Life 800-681-7177 wfbhealthcare.com

Articles in this issue

Links on this page

Archives of this issue

view archives of Good Fruit Grower - August 2016