Coastal fog is rotten for grape growers

If you see a grape grower, give him a hug. He probably needs it.

Growers are enduring one of the most stressful seasons in recent memory due to tough economic conditions and the European grapevine moth invasion.

And now a new threat, known as green rot, has emerged in Sonoma County vineyards because of persistently damp, cool weather.

Green Rot In Sonoma County Vineyards


The outbreak of green rot in the Russian River Valley is the worst since farmers first started noticing it in the 1970s, said Duff Bevill, founder of Bevill Vineyard Management in Healdsburg.

"It's been a long time since it's been this cold. The green rot is a telling indicator," Bevill said. "This is a year for disease."

Green rot is technically Botrytis, a mold that infests grape clusters and destroys the fruit. Botrytis usually doesn't appear in great quantity until much closer to harvest, often triggered by early rains. Late in the season, growers call it bunch rot.

But "this mold is already taking off. It didn't wait for the rain," said Rhonda Smith, a viticulture adviser with the UC Cooperative Extension in Sonoma County. "The thick marine layer has provided the moisture."

When Botrytis makes an early appearance like this, farmers give it a unique name because it forms in young, unripened grape clusters that are often still green -- hence green rot.

Once the mold takes hold, it spreads, so farmers have little option other than to prune infected bunches.

"We've probably had to cut off 3 tons," said Kyle Cameron, 14, who helps manage the family's 10-acre Sunny Valley Vineyards in Fulton. "Every year you find a little bit. But this year is much more."

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