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European Grapevine Moth Letter: UC Davis Extension EGVM updates for finds in and around Solano County

Please take a moment to read the email below this from Monica Cooper from UC Extension For those growers/vineyard managers with grape vineyards that are within 500 meters of the 2010 European Grapevine Moth (EGVM) finds in Solano, a letter sent earlier this week pertaining to EGVM treatment for 2012. In the letter, we ask that grape vineyard(s) located within 500 meters of a 2010 EGVM find are treated for the EGVM first generation in accordance with the treatment recommendations provided in the attached document: European grapevine moth (Lobesia botrana) in California.

Treatment timing for 1st generation  applications in 2011

After vineyards have been treated for the EGVM first generation, please:

  • Notify me either by telephone at  707-784-1310 or by email at shortly after you have completed treatment of your vineyard(s) for EGVM.
  • Submit Pesticide Use Reports that include your treatments for EGVM no later than the 10th day of the follow month after the treatment.

It is critical that we receive your Pesticide Use Reports for EGVM treatment as we must ensure timely reporting to the USDA. To date, we have had a total of eleven EGVM finds in Solano County, all of which occurred in 2010. Due in part to your efforts in participating in vineyard treatments within 500 meters of the 2010 EGVM finds, we have had no further  finds in Solano  County since 2010. Neighboring us, Napa  County caught a over 100,800 moths in 2010, with 99,000 moths caught in the first  generation.  In 2011, Napa County caught 113 moths, with 96 moths caught in the first generation. Please keep in mind that in 2011 there  was a find in Napa County just north of the Solano County border off of Gordon Valley Road  that may likely impact potential future quarantine adjustments when considering the TWG recommendations discussed below.

So far for 2012, there have been only 4 moths caught on three sites over the past two weeks in Napa County. The EGVM Technical Working Group (TWG), which is composed of a panel of scientists from around the world who have expertise in controlling EGVM, convened in Sacramento in  mid-December to discuss the 2011 year’s program activities and to make  recommendations for the
program’s continued progress in 2012. In late January, the TWG provided a finalized written report of recommendations for regulatory policy and management practices for EGVM in California.

The following TWG recommendations apply to Solano County and are adopted for  2012:

  • Reduce quarantine areas throughout the State from 5 miles surrounding detections down to 3 miles from detections.
  • Those portions of  Solano that are  over 3 miles of any find site that occurred in Napa County, could potentially be deregulated (removed from quarantine) as early as August 2012 provided  that:
    • trapping levels within 500 meters of  detections made in 2010 are conducted at 100 traps/square mile for the first  two generations with no additional finds, and
    • grape vineyards within 500 meters of  detections made in 2010 around find sites (500 m) are treated for EGVM at  least the first generation of 2012.

Continued participation in ensuring treatment of vineyards within 500 meters of EGVM finds for at least the first generation in 2012 is important in the goal our  eventual exit strategy from quarantine for Solano County. Provided we do not find  any more moths, we will not ask you for the second or third EGVM generation treatment. If you have any  questions pertaining EGVM, including treatment and quarantine requirements, please feel free to call or email me.

Best  regards,

Linda  Pinfold Deputy  Agricultural Commissioner/Sealer
Weights & Measures Solano County  Agriculture Department 501 Texas Street
Fairfield,  CA 94533 Phone: 707-784-1310  Fax: 707-784-1330

Sent: Friday, May 04, 2012 9:29  AM
To: Pinfold, linda
Subject: New Issue of  European Grapevine Moth Available 1st flight  and 1st generation treatment  update:

It is time to treat for the 1st generation of Lobesia larvae. Ideally treatments should be applied between cluster elongation and the beginning of bloom. Applications should be made before 5% bloom. Starting May 7, in Napa Valley and a week later in cooler areas, treatments can be combined with fungicide sprays anytime during the next 3 weeks. Hillside vineyards that are behind Oakville vineyards can be treated at the later end of the 2-3 week period, depending upon cluster development. Organic growers will need to make multiple applications, at 7 to 10 day intervals. We are inferring that the peak of the 1st flight of Lobesia in Napa occurred during the week of April 23. This is based on recent trap catches, degree-day model calculations, and our experience with Lobesia over the last 2 years.

Most eggs  are laid during the peak flight period. We expect these eggs to hatch in 118 DDF. From April 25 to May 2, we accumulated 93.22 DDF in Oakville. Once most eggs start hatching, there will be a window of 2-3 weeks to control small larvae. For those following degree-days, here are historical numbers for Napa (Oakville CIMIS) for the peak of the 1st flight:

  • 2010: April 19 (485 DDF)
  • 2011:  April 19 (572 DDF)
  • 2012: week of April  23 (588 DDF).  _Download and view the newsletter here. (Click)

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