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Red blotch: the grapevines' newest threat

April 08, 2013

At first glance, it seems similar to other common viruses that turn infected grapevine leaves beautiful reds in the fall, but it's distinctive and not even officially classified yet. It keeps grapes from ripening fully and accumulating enough sugar, typically limiting it to no more than 20 to 21 percent compared to 24 to 27 percent in healthy vines.