Welcome and Announcements

Old Business At the April Russian River meeting a question was raised about materials to loosen clusters like giberellic acid, which is used in table grapes. Tight clusters are more susceptible to bunch rot, and after last year folks are interested in learning how to reduce it in the future. Paul Michalczyk’s winemaker does not like to have boron or zinc applied to the vines in order to reduce set and cluster tightness. Marty Hedlund recalled GA trials conducted by Jack Foote in Santa Maria zinfandel in the 70’s that gave good results the first year, and too variable results the second year.

Review Cooperator’s Block a) Russian River Appellation—Host Dennis Devitt at Laguna Ranch Yanmar rubber track tractors are working well. Reliable. Dennis is finishing thinning and on his third fungicide spray. This will be Flint, Thiolux, Zn + B. The first two were 1# Kocide 3000 and ½% JMS Stylet oil with electrostatic sprayer at 40 GPA. The oil eradicates fungi and reduces mites but leaves the predators intact.

b) Sonoma Valley Appellation—Hosts Tom Gore and Mel Dagowitz at Barricia Vineyard Tom is on his third spray and will be using wettable sulfur, Rally, ZN + B. Copper only in first spray. In some Alexander Valley blocks, Tom delayed shoot thinning til growth had slowed, then went through in one pass, and though it was slow, it actually was less expensive than doing shoot thinning earlier and having to come back through for leaf removal. This would not be something he’d do in a mildew or rot prone area.

c) Dry Creek Valley Appellation—Host Richard Rued at Rued Vineyard Richard talked about water issues in Dry Creek Valley, including potential recycled water use. Growers have 0 to 4 sprays on, depending on location and farming style. Don Mitchel saw some carignane in Asti with a little mildew already. The grower has not sprayed yet, as is his normal program. I guess it gets reliably hot enough to kill the mildew eventually.

d) Alexander Valley Appellation—Host Dana Grande at Jordan Vineyard Dana is on her third fungicide application and will be using oil. She started with sulfur. Several other growers are also using oil, often to reduce chronic populations of mites, mealybug, scale, or leafhoppers in addition to eradicating fungal infections.

Focus Points  Mildew – Mark Lingenfelder noted that there have been 5 to 7 ascospore releases since budbreak. Adcon mildew risk index is increasing in most appellations and is in the high-pressure zone in warmer areas such as Dry Creek and Alexander Valley. When the model reads 20 or better for 3 consecutive days mildew is “off and running”. The last spray before bloom is often when folks start using DMI’s or strobilurins for their long-lasting effect, so that bloom can be finished before needing to spray again. Some folks are using high rates of Pristine for its suppressive effect on botrytis, too. Others with chronic botrytis pressures will use a dedicated botrytis material, Elevate or Vanguard, with a DMI or strobi for the mildew. To receive the free powdery mildew risk index readings contact dowagrofax@yahoo.com. It has twice weekly reports from 11 stations through Napa and Sonoma.

Heads up • Light Brown Apple Moth (LBAM) – From the Sonoma County Ag Commissioner’s office: “On May 2, USDA implemented a Federal Quarantine to restrict the interstate movement of certain regulated articles in the eight infested counties (Napa is likely to be added) and Hawaii, requiring visual inspection, certification, trapping, and treatment applications. The current rules relating to intrastate movement will be revised to mirror the Federal requirements. Also, on May 4 Mexico notified USDA of its restrictions for movement of certain commodities from infested counties to Mexico. In response to the LBAM situation in California, USDA and CDFA have assembled a technical working group comprised of international experts to discuss survey and mitigation strategies to safeguard against this potentially damaging pest and prevent its further spread. The group is meeting in San Jose May 17-18 to discuss California’s situation and make recommendations on survey methods, mitigation tools, and eradication strategies.”

• Report of chelated zinc from Western Nutrients precipitating out of solution in a jar test.

• Oil use as an early season fungicide/miticide can allow erinium mites to build up. They are generally not a problem when sulfur dust is used for fungal control. These mites primarily cause aesthetic damage. Paul Kaselonis has treated a particularly active outbreak in sauvignon blanc with Acramite.

General • Ferrari-Carano’s 15’ – 30’ high shade cloth fence has been working to keep BGSS out of the vineyard. Paul Kaselonis noted that trap counts inside and outside the fence have been telling, and they will be seeing the difference in vineyard replants. • Growers are gearing up for petiole sampling. • Kevin Skene is trying Pyganic on high population of adult overwintered GLH. Will report back on the success. • Lucia has a grant for a materials and timing trial for VMB. We will use the results to better manage VMB. • Sandy Henson is seeing Argentine ants at the PVC ant bait stations she put out a few weeks ago. Joan Griffin is using the KM Ant Pro stations and is also seeing a good ant turn out. • Weeds are doing well – spring annuals and grasses seeding out, summer weeds developing. • Devigorating vines: Brett Munselle runs a kicker cane along the drip line, and it is easy to take off. Ginny Lambrix removes extra vegetation from overly vigorous vines before the leaves harden off, as they become net exporters of energy to the vine after hardening off.

What is it? • Necrotic spots and lesions on a syrah shoot brought in by John Kiger were not definitively identified. It may have been spray associated, since the shoot had spots only on one side. They resembled phomopsis, but John has never seen this before.

Adjourn - Thanks for coming!