Within the United States, Washington is the number one producer of Concord grapes and the number two producer of wine grapes. Previous studies in wine grapes revealed the presence of twelve different viruses in Washington vineyards. Despite what is known about viruses in wine grapes in Washington, virtually no studies have focused on viruses in Concord vineyards. To further understand the epidemiology of viruses in Washington State, a survey of Concord grapes was conducted in 2010 and 2011. Five hundred Concord vines were sampled and tested for the presence of virus, and five different viruses were found among 92 virus-positive samples. The most common virus found was Grapevine leafroll-associated virus 3 (51 samples), followed by Grapevine fanleaf virus (24 samples), Grapevine leafroll-associated virus 4 (nine samples), Grapevine leafroll-associated virus 2 (four samples), and Grapevine leafroll-associated virus 9 (four samples). The presence of viruses in Concord vineyards is of great concern for growers due to likely movement of virus diseases from Concord grapes to wine grapes that might result in economic losses to the grape industry.
Accepted for publication 19 May 2012. Published 5 August 2013.