SonomaCountyWinegrape Commission

June 2012

Grower Appellation Meeting Notes

Welcome and Announcements

  • Grant from Western Region Sustainable Ag Research and Education program is supporting these meetings. The grant will include frost protection, soil and plant water status, and irrigation initiation.

General Topics

  • Summer annual weeds mare’s tail, willow herb, puncturevine coming up.More sightings of Johnson grass than usual. One grower mentioned the use of a shop vac with the filters removed to pick up puncturevine seeds. John Roncoroni’s herbicide trial in Napa had no fluvellin in the untreated control plots due to other annuals easily outcompeting it.
  • Mark Greenspan commented on recent (Summer 2012) Sustainable Winegrowing Alliance newsletter cover story “’Big Drink’ Equals Big Savings in Water Use”. The strategy is to water vines less frequently but with more water. It is not appropriate for shallower vineyards. Mark recommends watering to the weakest vines in the vineyard, using more frequent and shallower irrigations, perhaps “The Little Sip” strategy? This will help provide more uniform vigor across the vineyard.
  • Nursery stock: shortage means growers would be well advised to take care in assuring healthy stock before planting. After they’re in the dirt, accountability is hard to determine. Current certification covers virus, not fungi or insects. Expect more black goo, cylindrocarpon, vine mealybugs, etc.
  • Oak root fungus – try not watering it, or giving the vines as little water as they can live on. The fungus becomes very active in warm weather with water. If there’s a chronic area, dry farming St George might be an option
  • For those with mechanical leafers, this is a good year to get your money’s worth. Richard Rued had his leafer out for us – it works well, especially in the morning when leaves are crisp. Other growers are finding a shortage of labor, which may set the vines up for mildew &/or botrytis since spray coverage can be hampered by dense canopies.
  • Mark Houser is tipping his malbec and using Triggrr to help set fruit. He sees about 40% yield difference with this treatment.

Heads up

  • BGSS and Pierce’s disease:
  • Vegetation management is an effective way for reducing PD.
  • Concentrate on the “Big 5” – vinca, blackberry, mugwort, elderberry and wild grape (also English ivy and liquid amber in ornamental settings).
  • The old school “if a little is good, then more is better” method of clear cutting riparian areas is undesirable.
  • Limbing up trees and removing the understory can create more problems than it solves:
  • it makes better habitat for blackberry, vinca and mugwort;
  • it opens corridors into your vineyard providing direct access to BGSS;
  • it reduces bank stability and puts your vineyard & roads at risk as well as increasing sediment in the watercourse;
  • limbing up trees invites dead arm into them and can increase the incidence of dead arm in your vineyard, not to mention jeopardizes the trees and exacerbating bank stability. Loosing vines by a creek can be from PD or dead arm – ID it correctly.
  • EGVM – Napa still has the only finds this year. Make sure all equipment is free from debris if it’s coming from Napa. In planning for sugar sampling, do not take grapes off site from Napa.

Monitoring Points

  • GLH –Populations still light for the most part. A few hotspots here and there.
  • Mites – few mite issues reported
  • Gophers – Barn owls seem to be having a good year.
  • Mildew is starting up on sensitive varieties in warmer areas – chardonnay in Alexander Valley and Glen Ellen, carignane in Dry Creek. Wind has delayed sprays.