(PD) - One of the biggest threats to vineyards local grape growers face is powdery mildew, a fungus that can ruin their crop if left unchecked.

But spraying can be problematic, so the more than 200 vineyard owners and managers who attended the annual Sustainable Winegrowing Day at Forestville’s Shone Farm Tuesday were eager to learn of new technologies to help keep the fungus at bay and limit spraying at the same time.

The event was sponsored by the Sonoma County Winegrowers, the trade group that represents local vineyard owners and managers.

“It’s huge. Of all the things a grower faces in a year, powdery mildew is the most significant,” said Laura Breyer of Breyer’s Vineyard IPM Services in Windsor.

One new development is a device that can trap spores of the powdery mildew and use DNA sequencing to determine if there is in fact an active fungus present that could diminish the crop, said Bryan Rahn, a soil scientist at Coastal Viticulture Consultants in Angwin.