Two weeks ago, I first wrote about the European grapevine moth (EGVM) in a comprehensive story: The European Grapevine Moth, less welcome than your mother-in-law, is here. Since then, I had a chance encounter with one of the big wheels at Brutocao in Hopland who spoke to my concerns for the unique county wide passion for organic and biodynamic grape farming in Mendocino county in the face of the real threat of complete crop loss to the pest.

While there are completely effective insecticides that can be used by organic farmers, Dipel BT and Entrust Spinosad, they rely on ingestion by the caterpillar rather than acting through simple contact, they also have short periods of efficacy. While the organic options cost no more than their more powerful less green alternative insecticides, the organic insecticide cost is 10-12 times greater due to the need for larger and more frequent applications. Realistically, this means that some vineyards will abandon organic or biodynamic practices and certification; especially in a down economy when expenses cut closer to the bone.

In a conversation today, Mendocino County Agriculture Commissioner Tony Linegar confirmed the higher costs associated with treating the EGVM risk organically, and acknowledged that it hits Mendocino county especially hard because of the county wide dedication to greener agricultural options.

Commissioner Linegar remains optimistic that the infestation can be controlled and the threat to county agriculture fought and won. In addition to the 32 moths found at Dunnewood in north Ukiah, there have been just three single moths trapped; one in an Oak Knoll residence back yard, one in downtown Ukiah near Maple Restaurant, and one in a vineyard directly across from Weibel Vineyards three miles east of Hopland.

The EGVM is not a distance flier, it is suspected that the most found downtown Ukiah may have hitched a ride on a produce truck delivering to Maple Restaurant, and the moth found in Hopland came from trucks that had visited neighboring infested counties then parked for hours in the vineyard where the moth was trapped. It is known that Dunnewood had received fruit from Napa county.

Commissioner Linegar sees an end to the practice of transporting pomace from vineyard to vineyard. Pomace is used by some grape growers as part of a natural fertilizer. Linegar’s commission also will be enforcing tighter regulations regarding composting pomace, ensuring a minimum number of turns and a sustained temperature of 130° F. over 15 days.

Additionally, trucks moving from vineyard to vineyard will need to be cleaned completely, typically by power washing to remove all plant material. Meetings are ongoing regarding how this will be carried out in light of the remoteness of some dry farmed vineyards. Linegar said that there will be random inspections and failure to comply will result in fruit that does not make it to crush.

The EGVM has three cycles and we are coming up on the second shortly; Linegar feels that this is a most important time for Mendocino County’s wine industry and will determine much of what will follow in responding to the EGVM. While spraying of insecticide is voluntary, but recommended especially within a kilometer of a positive trap; increased numbers of moths, if found in the second cycle, could trigger mandatory spraying.

Both Napa and Sonoma Counties have established EGVM infestation, Mendocino County’s moth problem is in the early stages. With 70% of our grapes leaving the county, denying fruit from Napa or Sonoma becomes problematic; and much equipment moves by truck between counties, vineyard to vineyard and vineyard to winery, so while Linegar was absolutely upbeat, positive, and hopeful, it is understandable that many in the industry are expressing greater concerns.

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