Issue link: https://read.dmtmag.com/i/307101
44 MAY 15, 2014 GOOD FRUIT GROWER www.goodfruit.com Mistaken identity Many scientists believe that red blotch has been in the grape industry for some time, originally being mistaken for grapevine leafroll disease. In East Coast grape-grow- ing regions, Fuchs has found the virus in young and old vineyards, some as old as 30 years. "We think it's been around for some time, we just didn't recognize it as a new disease," he said. In 2005, Dr. Naidu Rayapati, WSU plant pathologist, received a call from a Benton City, Washington, grape grower who was concerned about leafroll virus in a Syrah block. "Testing was negative for leafroll, so the grower thought the red leaves were related to nutrition," Ray- apati said. The block still had symptoms after several years of nutritional amendments, so last year it was tested again. "We found it had red blotch virus." Both red blotch and leafroll viruses show similar red leaf symptoms in red grape varieties. Leafroll virus is sub- tler in white varieties. WSU's Rayapati believes that when the new virus first showed up in Washington, everyone thought it was leafroll. Those whose vines tested nega- tive for leafroll mistakenly assumed leaf symptoms were related to nutrition or other factors. "Don't assume if you have red leaves that you have leafroll disease," said Rayapati. "If you have tested your vineyard in the past for leafroll and tests were negative, it could be that you had red blotch instead." Tests have confirmed that the virus is found in several appellations within the state. While he doesn't think red blotch is rampant in Washington vineyards, "it is here," Rayapati said, though incidence is lower than leafroll virus. Of note is the widespread detection of red blotch in Merlot clone 15. "Merlot 15 was a 'hot' clone in short supply from nurseries, so many growers sourced cuttings from vineyards instead of certified nurseries," Rayapati said. "They tested the vineyard for leafroll and, finding none, propagated wood for expanded plantings." Rayapati and state officials are in the second year of testing mother blocks of certified nurseries in the state for red blotch and other diseases, a project funded by a specialty crop block grant of the Washington State Department of Agriculture. Thus far, the new disease has not been detected in any mother blocks. Several other specialty crop grants, managed by the Washington Wine Industry Foundation, have funded disease education and outreach as well as the develop- ment and printing of a disease identification pocket field guide. The pocket guide is designed for use by vineyard employees and will be distributed later this year in Span- ish and English versions. Learning experience Rayapati said the new virus, while frustrating to grow- ers who planted certified material, is a learning experi- ence for the industry. "When it comes to viruses, growers can't be complacent and assume that certified material means vines are free of all diseases," he said. Certified means the vine is only free of those viruses for which it was tested. Washington's agricultural department is in the pro- cess of updating state regulations to add red blotch to the list of quarantined viruses and insects for imported plant material. PHIL BROWN WELDING CORP. PHIL BROWN WELDING CORP. PHIL BROWN WELDING CORP. +/64:22: 51(012 • 3:22: 51(5 • 125-5:%7)4:#:$:/6)76:%7,+76:1-10 888*+7) /8684)76*,/& the since '&'%"%'$ '&%%! '!& '$ $'#&' $'%& "# '#'&% '#%& '$ '#%&&% '# !'$ $!% "%! $"#&""#&$"!$ 9:339#::3!..:.'$9:3:3#!'"::99".9:9!'%9$" Contact Vine Tech Equipment your Northwest Phil Brown Dealer 0-( 55(0-00:::::888*7644,+4 7&46*,/& A properly planted tree produces like no other. • Adjustable tree depth. • Works on stony and tough ground. • Shoe swings for handling. • Electronic distance marker also available. • Two row tool bar available. TREE PLANTER Self-Propelled Work Platform Hydraulic Work Platform (sold separately) can be mounted on any available running gear. Marc Fuchs, Cornell University