A program funded by the 2014 Farm Bill can provide assistance to grapegrowers affected by red blotch virus.

Dixon, Calif.—California grapegrowers whose vineyards are affected by the Grapevine Red Blotch-associated Virus may be eligible for financial aid to replace infected vines under a relatively new program attached to the 2014 Farm Bill. The aim is to ameliorate the effects and limit the spread of the still-mysterious red blotch virus in many of the state’s major grape-producing counties.

The aid comes under the Farm Bill’s Tree Assistance Program (TAP), which provides financial assistance to growers whose vines are damaged by “natural disasters.” First emerging as an important issue in California vineyards in 2011, the vectors of red blotch have yet to be determined. The new malady is not caused by known viruses or other plant diseases, researchers said. It can cause major damage to grape crops by causing the fruit to not fully ripen.

Agri-Analysis LLC, approved by the California Department of Food and Agriculture (CDFA) to diagnose vine disease, continues to encourage growers to be vigorous in testing new planting materials so as to prevent any infected vines from being planted in new vineyards.

“In other crops, viruses of the geminiviridae family are known to be transmitted by whiteflies and leafhoppers feeding on plant phloem fluids,” according to Agri-Analysis. The company gives a status report and list of red blotch-related events here. “Some research suggests that the global climate change is causing the virus to migrate from tropical climates to new areas. However, it is too early to tell exactly what vectors harbor and transmit this virus in grapevines. Pest management guidelines are not yet available.”

Tales from the field
Speakers at the 2014 Unified Grape & Wine Symposium shared tales of red blotch, with Peter Opatz of Silverado Winegrowers describing a “nightmare” situation in a 40-acre Alexander Valley vineyard. “It was a great site, and it wasn’t until the third leaf that we found a problem with red blotch. The symptoms we noted could almost be attributed to deficiencies with phosphorus or potassium at first.” The vines had many red and pink leaves, and the grapes stopped accumulating sugar at 19º Brix.

After Jim Wolpert from the University of California, Davis, confirmed the culprit was red blotch, the grower sold off the grapes to a winery that then paid for Mega Purple flavoring and concentrate to make them usable.

Tap into TAP funds
Before starting the process to receive TAP disaster relief, Marianne Morton, executive director of the Napa/Solano County USDA Farm Service Agency (FSA), advised that growers must verify red blotch is present where suspected. Specimens must be submitted to an approved commercial lab for analysis.

Further, she summarized:

• Vines cannot be removed before inspection by a Farm Service Agency (FSA) employee. Your county FSA will send a loss adjuster to visually inspect the vines.

• Producers may receive assistance for a maximum of 500 acres annually.

• The first 15% of loss is not covered.

• Maximum payment rates: $4 per vine replacement; $2 per vine planting; $500 per acre for site preparation.

It’s not necessary to remove entire vineyard blocks, only the infected vines. The process moves relatively quickly. To date, Morton said, “We are getting one or two inquiries weekly from Napa, nothing yet from Solano or Yolo counties.

Last year, Wines & Vines reported that the spread of red blotch was stalling grapevine deliveries from commercial nurseries, so it’s recommended that growers start the process as soon as possible.

TAP’s red blotch compensation is limited to growers in specific California counties, including: Amador, Contra Costa, El Dorado, Fresno, Marin, Mendocino, Monterey, Napa, Riverside, Sacramento, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Cruz, Solano, Sonoma and Yolo.

For more information, growers in Napa/Solano counties should contact Bonnie Nogales at (707) 678-1931, ext. 102. Find contacts for other counties here.