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European Grapevine Moth in several counties

The European Grapevine Moth (EGVM) is popping up everywhere in the California.

It was found last week in Merced County, and has been detected in four counties on the North Coast and 200 miles south in Fresno County, the state’s No. 1 grape-producing county.

When it’s found, growers go after it in a hurry with pesticide applications to head off any damage and spread of the pest that is spawning large quarantined areas.

If not controlled, Lobesia botrana can devastate an entire vineyard.

The first incidence of EVM was confirmed last September in Napa County — the first ever in the U.S. The moth was found in traps at 27 locations in Napa last fall, and has been detected this year Mendocino, Lake, Solano, Fresno and Merced counties.

Since nocturnal moths can fly only a relatively short distance, it is assumed that they move from one area to another by hitching a ride on machinery, trucks and other vehicles. They also may have moved on 2009 harvested grapes.

Depending on climate, EGVM may have as many as four generations a year. The first-generation larva feed on the vine’s flowers, which may fail to develop, or grape bud clusters. Larvae of the second generation attack green berries, hollowing them out and leaving just the skins and seeds. The third generation inflicts the greatest damage, feeding on ripening grapes and leaving them open to fungal infections of grey mold (Botrytis) and ruination.

Growers are wasting no time in taking aggressive action to prevent EGVM from gaining a foothold in California. At ground zero, Napa County, Napa Valley Grape Growers and Napa Valley Vintners have been leading the charge. Growers in quarantined areas sprayed conventionally-grown vineyards with either an insect growth regulator or a chlorantraniliprole formulation. Organic growers could choose from a Bt product or a spinosid.

Fewer moths were found in the traps after treatments. Growers in quarantined areas are cleaning equipment with high pressure water or air blasts before moving to other vineyards.

In Solano County, only one moth each has been found in seven of the traps, and no quarantine has been declared. Nevertheless, producers in the area where a lone moth was trapped have willingly applied insecticides that are effective against the eggs or the larvae, says Jim Allan, the county’s Agriculture Commissioner.

“Growers are anxious to eliminate the pest from the county and are very cooperative in doing whatever they can to help eradicate it.”

After multiple finds in Fresno County, the county’s Department of Agriculture and Information Technology Services Department have set up voice mail messaging system to keep growers informed on the latest information on EGVM. The number is (559) 600-EGVM.

Growers can call anytime. If growers have additional questions, they can leave a contact phone number and a time convenient for a return call.

In addition, the county agricultural commissioner and the University of California Cooperative Extension have scheduled three upcoming meetings to discuss EGVM:

May 19 —Kearney Ag Center, 9240 S. Riverbend Ave., Parlier, Calif., 10 a.m.-Noon.

May 22 — California Tree Fruit Agreement, 975 I Street, Reedley, Calif., 10 a.m.-Noon.

May 27 — Fresno County Farm Bureau, 1274 W. Hedges, Fresno, Calif., 6-8 p.m.

TAGS: Management
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