Grape growers from Lake and Mendocino counties are lobbying for federal disaster aid as a result of smoke damage to their crop from the Mendocino Complex fires this summer.

Lake County growers have already lost at least $37.1 million from smoke-tainted grapes this year, according to a survey by the Lake County Winegrape Commission. The 2017 crop was valued at $84 million before those grapes were turned into wine.

Likewise, Mendocino County grape growers are expected to release their own survey soon that also will show they suffered extensive losses. That crop was valued at $120 million last year.

Local and state winegrape industry officials on Sunday sent a letter to U.S. Rep. Mike Thompson, D-St. Helena, asking him to push to include the industry in disaster-aid legislation that may move through Congress soon. That effort is specifically designed to help timber growers who were harmed by Hurricane Michael that barreled through Florida, Georgia and Alabama last month.

“This year, persistent exposure to heavy smoke, produced by uncontrolled wildfires, resulted in substantial losses to winegrape growers in Lake and Mendocino counties,” wrote John Aguirre, president of the California Association of Winegrape Growers, along with leaders of various farm groups from Lake and Mendocino counties.

“When grapes subjected to heavy smoke exposure are processed into wine a matrix of compounds may be released that impart smoky, ash-like aromas and taste to the resultant wine,” they wrote.

Numerous Lake County growers have seen their contracts canceled by big wineries such as Treasury Wine Estates and Constellation Brands Inc. over such smoke concerns. They have been forced to either discount their winegrape crop, make their own bulk wine out of the questionable fruit, or in the worst case scenario leave it hanging on the vine and hope their crop insurance will cover the losses.

The local growers are asking Congress to extend a program that covered some industry losses from the 2017 California wildfires into this year’s fires, and allow that relief to go into 2020 to provide a safeguard for problems that may be discovered during bottling or in the marketing of the wine. The groups also want the U.S. Department of Agriculture to establish a better testing protocol to detect for smoke compounds in grapes and $5.25 million to support research on smoke exposure to winegrapes.

“With so many constituents in the grape-growing community, I am acutely aware of the challenges facing many growers in Lake and Mendocino counties following this summer’s tragic fires, Thompson said in a statement.

“I am working with my colleagues to pursue every avenue of federal assistance,” he added. Thompson owns a 20-acre vineyard in Lake County.

You can reach Staff Writer Bill Swindell at 707-521-5223 or bill.swindell@pressdemocrat.com. On Twitter @BillSwindell.