Famed Winegrape Region Quarantined
March 10, 2010 In response to numerous detections of the European grapevine moth (EGVM) in Napa County, the California Department of Food and Agriculture (CDFA) has established a quarantine of 162 square miles including portions of Napa, Sonoma and Solano counties.
The initial detection of an EGVM larva in a trap in the Oakville area on September 15, 2009 was the first detection of this pest in the United States. Confirmation of that detection led to increased trapping and surveys that have since detected the pest at several sites, generally contained in two pockets of infestation: one on the eastern side of the City of Napa and the other between Oakville, Rutherford and St. Helena. Maps of the two quarantine zones and additional information are available at www.cdfa.ca.gov/PHPPS/PE/InteriorExclusion/egvm_quarantine.html.
“Grapes are our state’s top crop,” said CDFA Secretary A.G. Kawamura. “This quarantine will help us ensure that the infestation doesn’t have an opportunity to spread. I fully understand that quarantines impact both the public and our growers. It is important and necessary to protect our food supply and the larger environment from these invasive pests, so the entire community’s cooperation is essential and appreciated.”
EGVM, or Lobesia botrana, is found in southern Asia, Europe, North Africa, Anatolia, Caucasus and in South America. The pest primarily damages grapes, but has also been known to feed on other crops and plants. For more details on the pest, check out the story in the April issue of American/Western Fruit Grower.
Inspectors are working with growers, nurseries, landscapers and others who work with plants and fruit to guard against spread of the pest by regulating the harvest, shipping and handling of affected crops and plants. CDFA and local officials will plan grower meetings to make sure the agricultural community understands the quarantine regulations.
Residents of the quarantined area are asked to review the list of host plants/fruits (below) and to not remove them from their property; the produce may, however, be harvested and consumed on site.
| Scientific Name | Common Name |
| Actinidia chinensis | Kiwi fruit or Chinese Gooseberry |
| Berberis vulgaris | European Barberry |
| Clematis vitalba | Old-Man’s-Beard or Traveller’s Joy |
| Daphne gnidium | Spurge Flax |
| Dianthus spp. | Carnation |
| Diospyros kaki | Persimmon |
| Galium mollugo | False Baby’s Breath or White Bedstraw |
| Hypericum calycinum | St. John’s Wort or Aaron’s Beard |
| Ligustrum vulgare | European Privet |
| Olea europaea | Olive |
| Prunus spp. | Stone Fruit (e.g. apricot, cherry, plum) |
| Punica granatum | Pomegranate |
| Rhus glabra | Smooth Sumac |
| Ribes spp. | Currant, Gooseberry |
| Rosmarinus officinalis | Rosemary |
| Rubus spp. | Blackberry, Dewberry |
| Silene vulgaris | Bladder Campion |
| Trifolium pratense | Red Clover |
| Urginea maritime | Sea squill |
| Vitis spp. | Grape |
| Ziziphus jujuba | Jujube |
The EGVM larvae, not the adult moths, are responsible for the damage to grapes. Larvae that emerge early in the spring feed on grape bud clusters or flowers and spin webbing around them before pupating inside the web or under a rolled leaf. If heavy flower damage occurs during this first generation, the affected flowers will fail to develop and yield will be reduced.
Second-generation larvae enter the grapes to feed before pupating inside the grape. Larvae of the third generation — the most damaging — feed on multiple ripening grapes and expose them to further damage from fungal development and rot.
In the Oakville area of Napa County, where the original infestation was detected last fall, one grape grower lost his entire harvest.
CDFA, working closely with the USDA and county agricultural commissioners, has begun an intensive statewide trapping effort to determine whether the moth has infested any other areas of the state. In addition to traps already deployed in Napa and the immediate area, an array of traps is being deployed beginning in the warmer, southern region of the state, and progressing northward as the spring weather arrives, grapevines come out of dormancy, and the moths begin to emerge if they are present.
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