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Viticulture Notes
Vineyard and Winery Information Series:
Vol. 20 No. 3, May-June 2005
Dr. Tony K. Wolf, Viticulture Extension Specialist
What are the solutions to avoid or at least minimize neighbor concerns about vineyard spraying, or correct existing problems? Your neighbor likely won't move, so avoidance and active measures to minimize strained relationships will be more productive than will wishful thinking. Our site selection bulletin mentions the issue of vineyard location relative to neighbors, but does not offer solutions to overcoming conflicts either before they arise or after they have developed. Discuss the prospective vineyard enterprise with neighbors and be forthright about vineyard production practices, especially the need for protective sprays. Be candid about the materials you plan to use or are currently using: provide label specimens if they are interested, or web sites for label information (e.g., Crop Data Management Systems, Inc. -- http://www.cdms.net/manuf/default.asp). You can try the route of explaining relative toxicities of pesticides; however, this might be a moot point to a person who has taken a firm, if not objective, stance on the issue of pesticide application and pesticide safety.
Drift or movement of pesticides off-target to sensitive areas is a prescription for heightened antagonism against vineyards and must be avoided for both legal and public relations reasons. Particularly sensitive areas are houses, playgrounds, animal confinement areas, ponds, riparian areas or wetlands and roads and parking areas. The applicator is responsible for avoiding off-target drift of pesticides, and the product label typically includes language to this effect. Where "drift" starts to become a bit fuzzy is dependent upon the extent that your neighbor is willing to sample and test for drift. Let's look at the options to minimize the likelihood of ANY drift onto neighboring property.
Buffers: Avoid planting right up to neighboring property. A safe setback is probably on the order of 150 to 300 feet, but the distance requirement will be a function of the average spray particle size, the wind speed during spraying, and other peculiars of the spray conditions. One reference states that a 100-micron sized droplet will travel approximately 75 feet if starting at 10 feet above ground in a 5 mph breeze. Augmenting the buffer with a vegetative wind screen is an effective means of further reducing drift, and also provides some visual-screening of vineyard operations. Fast-growing evergreens such as Leyland Cypress are one choice for this purpose; however, check with local extension agents or horticulturists to be certain that the selected buffer trees do not have peculiar pest or stress problems of their own. Check the terminal growth height of the trees/shrubs used as vegetative barriers and plan enough of a set-back with vineyard rows so that vines are not competing for moisture and sunlight. As a general guideline, the minimum height of the buffer should be double the release height of the pesticide. Thus, for our vineyard situation (release height up to 10 feet (upwardly directed air-blast sprayer), we would want 20-foot high trees (start planting!). A porous buffer - one that slows air movement but does not redirect it up an over - will remove more spray droplets than will a solid wall.
Consider buffers between the vineyard and surface water such as streams and ponds, or where topographic site features might concentrate runoff from the vineyard and discharge it into streams or ponds. Some pesticides are highly toxic to aquatics, even if having low mammalian toxicity. Grassed buffer strips or other vegetation will minimize the likelihood of pesticides being washed out of the vineyard through surface runoff.
Spray conditions: Do you need to spray? I am surprised by people in our industry who attend our field meetings and annual winter meetings where pest monitoring and fungicide spraying are discussed, and then continue to spray on a weekly schedule! We can do better than that, and cut about 25% of a season's sprays at least by getting out of the 7-day habit. What is the wind speed? At minimum, purchase an inexpensive anemometer and record the wind speed at the start and finish of your spray applications as part of your spray records. Most pesticide labels will state that the product is to be applied when wind speed is between 3 and 10 mph. Windless conditions would seem ideal, but calm conditions can be associated with inversion conditions that cause the volatile components of a spray to remain in the area longer than if a slight wind exists. What direction is the wind from? Most vineyards are subject to a prevailing wind origin, such as the west or southwest. If sensitive areas are downwind of the vineyard, you may need to exercise even greater caution in choosing when to spray. Consider spraying in very early morning or late-evening when wind speeds are generally lower (it's also cooler).
Spray equipment: At minimum, make sure that your sprayer is calibrated and targeting the canopy of vines, not the sky above the canopy. Choice of nozzle can affect drift by governing particle size. Select low drift nozzles that minimize fine droplets (< 150 microns - note, 150 microns is commonly considered a size below which droplets are more prone to drift). "Mist blowers" use relatively low volumes of spray (25 to 50 gpa), but typically generate a finer droplet (70 to 140 microns) than do conventional air-blast sprayers operating at 50 to 100 gpa. More advanced sprayer technology may be necessary in very sensitive areas: rotary atomizers, used with directed fans (e.g., Proptecª sprayers), tunnel or curtained sprayers, and recirculating sprayers (e.g., LIPCOª) do an excellent job of minimizing off-target drift. As Dr. Andrew Landers (Cornell University) has discussed with us in the past, standard air-blast sprayers are notorious for ejecting a lot of spray material into the air, increasing the potential for droplet drift. Some reduction in drift can still be achieved with these sprayers by operating at somewhat lower pressure and reduced fan speed, or even restricting the air intake of axial fans.
Canopy conditions: The vine canopy should intercept most of the spray and thereby minimize off-target drift. In early season (pre-bloom), the canopy is relatively sparse and more of the spray material will pass through the canopy and may be subject to drift. It is therefore prudent to use lower volumes, pressure and fan speeds early in the season. As the canopy develops, particularly post-bloom, application rates and fan speeds may be increased. Solenoids fitted to valves allow rapid turning on and off of spray material to independent sides of the sprayer. Sprayers can also be fitted with sensors to automatically stop the spray when gaps in the canopy are detected. At minimum, turn the valves off at the ends of rows when making turns.
Record-keeping: This discussion would be incomplete without a comment about spray record keeping. Private certified pesticide applicators are required by law to maintain records of all applications of restricted use pesticides for a minimum of 2 years. Commercial certified pesticide applicators are required to maintain similar records for ALL pesticides for a minimum of 3 years. Note: Both private and commercial pesticide applicators may be under additional posting and record-keeping requirements as provided by the Environmental Protection Agency's Worker Protection Standard. A good overview of record-keeping requirements is available from the USDA's Agricultural Marketing Service (http://www.ams.usda.gov/science/sdpr.htm). The AMS website also includes forms that can be used to capture the relevant and necessary information on pesticide applications. If you employ workers other than immediate family members, you will be subject to Worker Protection Standard record-keeping and other requirements. A useful guide to the Worker Protection Standard is found at the following address: http://www.vdacs.virginia.gov/pesticides/pdffiles/wps.pdf
The spray record, which should include weather conditions at the time of application, can substantiate your compliance with label prescriptions, including your observance of potential drift conditions at the time of applications. Vineyards are under increased scrutiny by the Office of Pesticide Services (OPS), a division of the Virginia Department of Agriculture and Consumer Services. Virginia has 11 Enforcement and Compliance inspectors within the Office of Pesticide Services. While a "clean" audit may not heighten your image with antagonistic neighbors, being cited by the OPS for numerous violations will certainly fuel the neighbors concerns.
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Most growers are familiar with the canopy trellis system VSP (Vertical Shoot Positioning). Perhaps the "VSP" acronym could also be helpful for remembering the three-pronged approach to managing mineral nutrition in the vineyard: Visual observation, Soil analysis and Petiole analysis. Though not necessarily conducted in that order, incorporation of all three methods is essential for monitoring and maintaining optimal vine nutrition.
Soil Analysis: Detailed soil analyses are recommended before vineyard establishment, mostly to determine the pH, soil organic matter (SOM), cation exchange capacity (CEC) and content of mineral nutrients available for plant uptake. Routine or "maintenance" soil analyses are recommended on an annual or biannual basis in vineyards for monitoring nutrient reserves and changes thereof due to uptake by vines and by agricultural activities such as fertilization and soil tillage. These samples are typically limited to pH, phosphorus, potassium, calcium, magnesium, zinc, manganese, copper, iron and boron; however, the addition of CEC and SOM to routine soil analysis will greatly improve nutrient management decisions. For example, changes in pH may occur over time with the addition of some nitrogen-containing fertilizers (i.e. sulfate of ammonia, ammonium nitrate and urea). Subsequently, lime application rates to manage such changes are based upon CEC and SOM. Soil colloids with a high CEC and SOM may contain larger quantities of exchangeable hydrogen and aluminum ions, inducing a lower soil pH (3). Soil tillage may decrease SOM both by increasing erosion and by introducing oxygen into the surface soil, which decreases SOM due to enhanced decomposition by microorganisms (1). Microbial activity in soil has been correlated with SOM content (2) and thus, periodical testing of SOM may also indicate the impact of farm practices on microbial communities involved in nutrient cycling.
Unlike the immediate, short term results of a foliar nutrient application, the effects of nutrient amendments to soil may take several years to be observed. For this reason, it is not pertinent to have the added expense of SOM at each annual or biannual testing, but rather every 3 or 4 years in each distinct management area. A portion of vineyard soil should also be submitted for analysis of nematode populations during vineyard establishment and again every 4 or 5 years. Activity by dagger nematodes (Xipinema spp.) impairs nutrient uptake and increases likelihood of virus infections in vines in the Mid-Atlantic. Analyses of SOM and nematodes are generally not included in basic soil test packages offered by laboratories and may be requested for an additional fee.
A note on soil nitrogen: In Virginia vineyards, nitrogen is generally omitted from soil analysis. A combination of petiole analysis and visual observation of your vines is recommended for determining nitrogen requirements.
Petiole Analysis: Nutritional recommendations during the vineyard establishment phase are based solely on the nutrient status or "reservoir" of available minerals within the soil of a given site. Once young and old vines continue to occupy the trellis, more precise management techniques become pertinent to determine nutrient status within vineyard blocks or even subsections of those blocks. Grape petiole analysis is recommended as an annual or at least biannual addition to a complete nutrient management program. Petiole analyses reveal the actual nutrients that the vines were able to remove from the soil and utilize and thus, indicate the effects of soil amendments and cultural practices on vine health. The time of season to collect petiole samples depends upon the standards adopted in that area. Bloom time samples may show more accurate levels of boron and zinc (less mobile), whereas late summer samples may be better indicators of potassium status. In Virginia, routine petiole sampling is recommended during full bloom, when about two thirds of flower caps have dropped from the clusters. Where bloom-time analyses indicate borderline nutrient levels, particularly in potassium, a second sampling is warranted in late summer (70-100 days post bloom). Consistent timing of sample collection with respect to vine growth stage may be the most important factor when comparing test results from year to year. The target values for nutrients (Table 1) have been standardized for petioles collected at full bloom and late summer in the Mid-Atlantic region. Target values for vineyard soils in the Mid-Atlantic are also provided in Table 1 for reference. Detailed instructions for collecting petiole samples may be reviewed in the attached pdf file.
Visual Observation: Frequent scouting trips in the vineyard throughout the season are an absolute necessity for identifying early stages of nutritional disorders in grapevines. Visual observation of vine nutrient status is free of charge and may be combined with disease scouting and other routine activities in the vineyard. Many viticulturists look at visual observation as a means of discovering nutrient deficiencies in vines or sections in a vineyard based on symptoms expressed on foliage. Observations of excessive vigor or nutrient toxicities, however, are also key indicators of how a nutrient management program is affecting vine growth. It is also important to realize that not all foliar disorders are nutritional in origin. Herbicide toxicity, for example, may express symptoms similar to nutrient deficiencies.
Additionally, vines located on hilltops may be subject to shallower or rapidly drained soil conditions compared to lower areas, and may more readily show deficiencies of water mobile nutrients such as nitrogen, potassium, magnesium and boron, especially during periods of drought. If uncertain about the nature of a disorder, a grower may wish to collect petioles from vines showing questionable growth patterns and submit them to a lab for a "diagnostic" nutrient analysis. Diagnostic petiole samples may be collected at any time of year and should always be submitted with a separate sample of petioles for comparison (collected from the same shoot position on healthy vines). Foliar disorders may be observed in the scale of an entire vineyard, section of vineyard, individual vine or individual leaf. Those disorders occurring uniformly in a vineyard are potentially a result of nutrient interactions or management practices whereas a biological disorder is suspect when an individual vine or patches of vines are affected. Successful diagnosis of foliar disorders depends upon grower experience. Soil and petiole analyses should offer some clues as to whether or not the disorder is related to plant nutrition.
Table 1: Target values for soil, bloom petiole, and late-summer petiole samplings.
| Nutrient | Soil | Bloom petiole | Late-summer petiole | |||
|---|---|---|---|---|---|---|
| Nitrogen | --z | -- | 1.2 - 2.2 | % | 0.8 - 1.2 | % |
| Phosphorus | 20 - 50 | ppm | 0.17 - 0.30 | % | 0.14 - 0.30 | % |
| Potassium | 75-100 | ppm | 1.5 - 2.5 | % | 1.2 - 2.0 | % |
| Calcium | *500 - 2000 | ppm | 1.0 - 3.0 | % | 1.0 - 2.0 | % |
| Magnesium | 100 - 250 | ppm | 0.3 - 0.5 | % | 0.35 - 0.75 | % |
| Boron | 0.3 - 2.0 | ppm | 25 - 50 | ppm | 25 - 50 | ppm |
| Iron | 20 | ppm | 30 - 100 | ppm | 30 - 100 | ppm |
| Manganese | 20 | ppm | 25 - 1000 | ppm | 100 - 1500 | ppm |
| Copper | 0.5 | ppm | 5-15 | ppm | 5 - 15 | ppm |
| Zinc | 2 | ppm | 30-60 | ppm | 30 - 60 | ppm |
| Aluminum | *< 100 | ppm | ||||
| Organic matter | 3 - 5 | % | ||||
| pH | 5.5 | V. labrusca | ||||
| 6.0 | hybrids | |||||
| 6.5 | V. vinifera | |||||
No single nutrient analysis exists for accurately assessing the nutrient needs of your vines. A combination of visual observation with soil and petiole analyses offers the best available information for maintaining vineyard productivity. These are indeed the criteria that your extension service will request before assisting with your management decisions. One recommendation would be to alternate the collection of soil samples in the fall and bloom-time petiole samples in opposite seasons (i.e. soil analysis this fall followed by petiole analysis next spring). Regardless of the trellis system used for your grapevines, we hope to see the incorporation of VSP (Visual, Soil and Petiole) analyses into your vineyard in seasons to come.
Seasonal Nutrition Update: As full bloom approaches, now is the time to contact your plant analysis laboratory for petiole submission instructions. A list of plant tissue analysis laboratories is available in Chapter 9 of The Mid-Atlantic Winegrape Grower's Guide. Sample kits from the Penn State Agricultural Analytical Service Lab are also available at the AREC in Winchester and will be mailed to you upon request (westover@vt.edu).
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18 Maryland Grape Growers' Association Summer Field Day at Copernica Vineyard in Carroll County. Practical viticulture information for Mid-Atlantic grape growers. 8:00 am - 4:00 pm. Advance registration is $35 members, $45, non-members if received by 11 June; otherwise $45 and $55 per person, respectively. Mail checks (payable MD Grape Growers Association) to Mr. Bill Kirby, 307 S. Hanson, Easton MD 21601 (410-822-4421). Visit www.marylandwine.com/mgga/ or contact Bob White at bobwhite@erols.com for information. Directions: From Western MD or Wash D.C area; Take I-70 east to route 97, or take 97 north from the D.C. beltway. Go through Westminster and proceed north on 97 to Union Mills. Turn right onto Old Hanover Road and take the first right (Deep Run Road). Proceed for approximately 4 miles, until you get to 1116 East Deep Run Road; newspaper boxes are on the right and two 55-gallon cans are on the left next to the long driveway with the address painted on them. From Baltimore and points east; Take the beltway (695) around to 795 towards Reisterstown. Exit onto route 140 and proceed to Westminster. Take the route 97 north exit and proceed as above to the vineyard. For more information call Emily or Jack Johnston at 410-848-7577. To reach someone the day of the field day call 443-618-0955.
20-24 American Society for Enology and Viticulture Annual Meeting in Seattle, WA. ASEV is the professional association for the industry. Presentations are mostly scientific in nature. A large trade show accompanies the meeting. A great place to network. Go to www.asev.org for more information.
22 Rappahannock/Madison County vineyard meetings (Virginia). Chattin's Run Vineyard, Vicki and Bill Edmands. Topics - Seasonal Insect Update, Grape Root Borer, Japanese Beetle Contol on Young Vines, VA Tech Entomologist, Dr. Doug Pfeiffer. Current viticultural situation and Management Strategies, VA Tech Viticulturist, Tony Wolf. Direction: From Marshall, take Rectortown road north (Rt 710), approximately 4.4 miles, turn left onto Maidstone Road, go ~ .5 miles to 8517 Maidstone Road.
26 Vineyard Management class at Linden Vineyards in Linden, VA. Wine grower Jim Law offers a series of excellent practical, commercial level and high quality workshops on a variety of grape growing and wine making topics. The focus of this session is the finer points of day to day management in a producing vineyard including canopy management, training, vine nutrition and pruning. Go to the Linden web site for information and registration www.lindenvineyards.com/.
July
13-15 American Society for Enology and Viticulture Eastern Section annual meeting and symposium at the Millenium Hotel in St. Louis, MO will feature a focus on the enology and viticulture of four groups of varieties of increasing importance in the Eastern US and Canada: Norton/Cynthiana, Traminette, Minnesota Varieties (Frontenac, LaCrosse, etc.), and Pinot Gris. Join a pre-conference tour of Missouri wineries on July 13. This meeting will also be coordinated with the International Grapevine Genomics Symposium, July 12 - 14. This Symposium is part of the Southwest Missouri State University (SMSU) Centennial Celebration and organized in cooperation with the International Grape Genome Project (IGGP). Visit http://www.nysaes.cornell.edu/fst/faculty/henick/asev/ for more information and registration.
27 Rappahannock/Madison County vineyard meetings (Virginia). Horton Vineyard and Winery (meet at the Winery ), Dennis and Sharon Horton. Insect Issues: Product Labels & Environmental Precautions, VA Tech Entomologist, Dr. Doug Pfeiffer; Crop estimation and crop outlook, VA Tech Viticulturist, Tony Wolf; Wine Quality Issues for Growers and Sensory Evaluation of Virginia Research Wine. VA Tech Enologist, Dr. Bruce Zoecklein Directions: From Culpeper: Take 29 south to Ruckersville, then take a left onto 33 east, the winery is 8 miles on the left.
August
4 Virginia Vineyards Association's annual summer technical program. Program is currently being developed. Location will be a combination of Barboursville Vineyards and Horton Winery (keep the date, details will follow).
13/14 Winemaking Basics and Advanced Winemaking at Linden Vineyards in Linden, VA. Wine grower Jim Law offers a series of excellent practical, commercial level and high quality workshops on a variety of grape growing and wine making topics.
17 The Pennsylvania Association of Winegrowers Annual Summer Walk Around at Clover Hill Vineyards and Winery in Breinigsville, PA. A practical, grower oriented workshop that covers a wide range of viticulture topics. More information forthcoming.
13/14 Winemaking Basics and Advanced Winemaking at Linden Vineyards in Linden, VA. Wine grower Jim Law offers a series of excellent practical, commercial level and high quality workshops on a variety of grape growing and wine making topics.
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"Viticulture Notes" is a bi-monthly newsletter issued by Dr. Tony K. Wolf, Viticulture Extension Specialist with Virginia Tech's Alson H. Smith, Agricultural Research and Extension Center in Winchester, Virginia. If you would like to receive "Viticulture Notes" as well as Dr. Bruce Zoecklein's "Vinter's Corner" by mail, contact Dr. Wolf at:
Dr. Tony K. Wolf
AHS Agricultural Research and Extension Center
595 Laurel Grove Road
Winchester, VA 22602
or e-mail: vitis@vt.edu
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