Forget the light brown apple moth; there’s a new bug pestering the state.
In September 2009, the European grapevine moth was discovered for the first time in California in the Napa Valley. Native to southern Italy, the fluttering winemaker’s nightmare produces larvae that feed on grape bud clusters and flowers. The damage opens the fruit to infection and rot, making it unfit for consumption.
According to the California Department of Food and Agriculture, the moth is capable of rapidly infesting entire vineyards and then spreading through wine-producing regions. Since the moth appeared in Napa, portions of eight additional counties have been placed under quarantine. The infected counties closest to the Central Coast are Fresno and Santa Clara counties.
The moth has yet to land in Santa Barbara County, but state and local agriculture officials are working hard to see that it stays out. Wine grapes rank as the county’s third most profitable crop (behind strawberries and broccoli), taking in more than $100 million each year.
“[The European grapevine moth] is a fairly serious pest that can really damage the fruit. The state has traps out in all the counties, including ours. They haven’t found any so far in ours,” said Guy Tingos, the county’s deputy agricultural commissioner. “The state’s intention is to eradicate it before it can spread.”
To eradicate the moth in affected counties, agricultural officials are currently removing and disposing of infected fruit from host vineyards. The state has also restricted the movement of grapes, vines, and certain farming equipment. Additionally, residents who grow grapes, stone fruit trees, and other “host plants” have been asked to harvest and consume their fruit onsite.
Besides fruit removal, the state and counties are encouraging grape growers to use Isomate-EGVM, pheromone-releasing twist-ties that disrupt the moth’s mating cycle.
According to information from the Department of Food and Agriculture, the twist-ties release pheromones very similar to those emitted by the female moths. Males detect the pheromone “scent” with specialized sensory organs and follow it upwind to locate and mate with the females. The twist-tie pheromones confuse the males and suppress mating and reproduction.
The eradication methods have met with considerable success throughout the state—so much so that officials recently lifted the quarantine on Lake County.
“We’re constantly trapping and surveying throughout the state,” Department of Food and Agriculture spokesman Steve Lyle said. “We’ve had tremendous success in Napa knocking down the pest population. We’re very optimistic about our eradication efforts.”
Lyle said the department has also received help from Mother Nature.
“[The moth] is in diapause right now, which means in the winter months it hibernates,” he said, adding that the department will have a “greater sense of what 2011 will look like” in relation to European grapevine moths once the spring starts.
Local vintners, however, are still expressing concerns about the insect and its ravenous pupae.
“It’s a tough pest to get rid of because it lays its eggs in the grape clusters. Once [the larvae] start feeding on the grapes, it’s very hard to control,” said Kevin Merrill, president of the Santa Barbara County Farm Bureau and general manager of Mesa Vineyard Management. -The company manages vineyards throughout the Central Coast.
Contrary to the Department of Food and Agriculture, Merrill believes “it’s just a matter of time” before the European grapevine moth makes its way to Santa Barbara County.
“It’s all around us,” he said. “We can knock on wood but it’s probably going to get to us.”
Contact Managing Editor Amy Asman at aasman@santamariasun.com.
This article appears in Feb 24 – Mar 3, 2011.
