Sonoma County Winegrape Commission

Sonoma County Winegrape Commission July 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. Mark Greenspan noted that in initiating irrigation, attention should be paid to frequency and length. He targets low vigor areas for determining how much and how long to water; shorter and more frequent water sets will help keep lower vigor areas green without over-irrigating more deeply rooted vigorous vines. This strategy may improve yield and quality. Growers can login to the irrigation project data site to see what information is being collected realtime – see access passwords at the end of these notes.

General Topics . Summer annual weeds mare’s tail, willow herb, puncturevine, morning glory, Johnson grass blooming now or will be shortly. Control before setting seed is the ideal no-brainer, but implementing amidst the reality of other critical farming operations is the challenge. For many weeds, mowing when they just begin to flower is effective in reducing or eliminating seed set. . Tolerance for late-blooming weeds that are not interfering with vine health or vineyard operations can lead to fewer mite, leafhopper and mealybug issues. The predators and parasites that help control pests often require pollen and nectar as adults. . Leafhoppers: Second to third generation. Overall, few reports of issues with leafhoppers to date this year. One of the thresholds for determining if treatment is needed is vine balance. With more crop this year, keep an eye on vine balance with leafhopper damage. The Model Leafhopper Damage sheet can help calibrate your estimate of how much damage is actually occurring. You can find this sheet by entering the search term “IPM Fieldbook” on the commission’s website. The sheet is in the Fieldbook. . A few mites reported here and there as deficit irrigation goes into effect and we get into summer temperatures favorable to mite development. . Mildew infestations still low in general. A few of the earliest blocks are just starting veraison. . Ted Klopp has found zinc phosphide oats effective for gopher control. ZP and ProZap are two brands. . Short labor supply has meant delay in timely management. Paul Bernier uses a pruning saw with the teeth ground off as a hedging machete. . Electrostatic sprayers are coming down in cost and are not only very effective at delivering material, they use less material and water, too. . Vanessa Peay reported bear damage at her vineyard in the hills by the coast. Suggestions included sonic noise makers, dogs, syrup of ipecac on store-bought grapes.

Heads up . Leaf gall phylloxera vs erineum mites: Andy Walker has recently found the leaf gall form of phylloxera at various sites in California. To distinguish from erineum mite blisters on leaves, a phylloxera gall will be a complete nodule whereas a mite blister will be an indentation on the leaf. For all practical purposes, the leaf gall stage of phylloxera has been previously absent in California and any sitings of it should be reported to Walker or Cooperative Extension. . 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 or allow sugar samplers to bring Napa grapes on your property. . New leafhopper found in California. Established in British Colombia and some US states, and similar to our grape leafhopper (Erythroneura elegantula). The Virginia creeper leafhopper (Erythroneura ziczac) could be as innocuous as LBAM or as important as VMB if established here. Some, but not all, of our local Anagrus parasites attack this leafhopper. The habitat is the same as grape leafhopper. The adults have many subtle differences from grape leafhopper, but perhaps the most obvious difference are two black spots on adult grape leafhoppers’ back, just behind the head. Grape leafhopper nymphs do not have distinctive spots but yellow and white patterns. Virginia creeper leafhopper nymphs do have darker markings.

Monitoring Points . Measles symptoms are starting to show up on fruit and/or foliage. Can resemble mildew on fruit, or Pierce’s disease on foliage. . Continuing on the topic of clean planting material from last month: James Stamp’s services range from full process and quality guarantee to simple shipment inspection at your site ([email protected]). If you do your own pre-plant vine QC, Walker and Wolpert’s guidelines are an excellent resource (Quality Guidelines for Grapevine Nursery Stock. American Vineyard magazine April/May 1996.). The Guidelines are a section of a three-part article providing information on how to work with nurseries to obtain the best planting material. Remember that if your plant shipment doesn’t meet with the physical guidelines, it could very well be due to pathogens affecting the vines’ growth. Nurseries may turn one growers rejections into another growers planting material; putting poor quality plant material in the ground can mean very significant long-term losses materialized as poor production & yield, and high management costs in maintaining or replanting sickly vines.

SCWC – SARE Grant Project Logins

For access to real-time soil moisture information:

To login please go to: www.ranchsystems.com and click "My Account"

Property ID: LANDSLIDE User name is: scwgc Password is: cupnblnt Both Landslide and Red Fan project locations will be available using this login.

For access to weekly vine water status information:

Go to avit.meristemtech.com and login as: Login Name: SCWGC Password: SCWGC2012! The current report will be maintained as a static document, or a current report may be run under irrigation reports header. Current water status may be viewed on a map as well.

Sotoyome, Middle Reach Russian River Project Login

Go to avit.meristemtech.com and login as: Login Name: Sotoyome Password: SRCD2012! Current water status report will be maintained as a static document. Soil moisture charts will also be maintained as static documents. Or, current water status may be viewed by running report under irrigation reports header. Current water status may be viewed on a map as well.