We generally like to share our pastures with other living things but there are exceptions. An insidious foreign invader has recently landed in California, and it’s putting our state’s valuable vineyards at risk. The European grapevine moth has recently been discovered in the Napa Valley. First discovered in Oakville last September, the moths are a major threat to vineyards in the region and likely all over California.
Woodside, with its several commercial wineries, and the many private plots of grapes around people’s homes, needs to be aware of this threat. The San Francisco Chronicle recently reported that the grapevine moth is considered to be a worse threat to agriculture than the light brown apple moth, another recently-introduced pest that we wrote about here back in 2008. The tiny beasts are known to be able to utterly destroy a vineyard’s bounty. One grower in Oakville lost his entire nine-acre harvest this year.
The threat has prompted the California Department of Food and Agriculture (CDFA) to QUARANTINE 162 square miles of Napa, Solano, and Sonoma Counties! The CDFA is launching an aggressive plan to try to contain the insects, which are common in Europe but have recently spread to parts of Asia and South America. More than 3,000 sticky traps have been laid to try to capture the insects. Hopefully, the quarantine on grapes and other plants will stop the moths from spreading quickly. If these methods don’t work, agriculture officials are already talking about pesticides, a remedy that proved hugely controversial during the height of the light brown apple moth scare.
With three life cycles per year, the small (one-quarter-inch) but hungry bugs attack grapevines several times. Its eggs are laid on the vines, one generation consumes the flowers, and the next generation eats the grapes and introduces a grape-rotting fungus into the fruit, and the third generation hides for the winter, according to Monica Cooper, the director of UC Cooperative Extension and an adviser to Napa County. She told the Chronicle, “The trick now… is to learn as much as possible about the moth, how it got here, how far it has spread and what methods will be needed to prevent it from establishing a foothold in the rest of California.” spurred two articles in the Chronicle (the one above and this one)
We think that the agriculture officials in San Mateo County need to be hyper-alert for this pest, and Woodside’s commercial wine growers and hobbyists should be on the lookout. Woodside Vineyards, Thomas Fogarty Winery, and others all produce wine grapes in and around Woodside and could take a major economic hit if the moth spreads – just like the light brown apple moth spread to engulf the entire Bay Area.
Other plants under quarantine in the affected area as possible hosts are: Kiwi fruit, European barberry, Old man’s beard (Traveler’s joy), Spurge flax, Carnation, Persimmon, St. John’s wort (Aaron’s beard), False baby’s breath (white bedstraw), European privet, Olive, Stone fruits, such as apricot, cherry and plum, Pomegranate, Smooth sumac, Currant, gooseberry, Rosemary, Blackberry, dewberry, Bladder campion, Red clover, Sea squill, Grape, Jujube. Source: San Francisco Chronicle.
Homeowners need to do their part as well and get educated, to be on the watch for this new grape predator. The creatures are very small and green and brown. See an image here and if you find an insect you don’t recognize on your vines, you should definitely alert County agriculture officials . Let’s all do our part to keep our grapes safe and our wines top quality!
Meanwhile CDFA has just certified its final Environmental Impact Report (EIR) for the Light Brown Apple Moth project. The program has shifted from eradication to suppression and control. The CDFA issued a clarification that aerial treatment with moth pheromones is not a management tool in the program. The only two treatment methods being considered currently are the placement of pheromone twist ties on trees and plants, and the release of sterile moths.