Renovating the OSU Research Winery

A vital component of the Oregon Wine Research Institute’s “vine to wine” research approach is the ability to conduct a large number of controlled, research scale fermentations. This has allowed studies such as “Managing Nitrogen in the Vineyard or the Winery” to be performed or the 2020 project where eighty-four micro-fermentations of smoke impacted grapes from all across Oregon were conducted to provide information on the impact of smoke exposure in different regions and on different grape varieties. While the current research winery has served us admirably in the past, it is undersized and underequipped to meet our current and future needs. This hinders the ability for OSU to conduct research to address current and emerging industry priorities, such as mitigating the impact of smoke exposure from wildfires and recruiting and training the next generation of winemakers and viticulturists. Therefore, the primary need of the OSU enology program is a well-equipped winery with increased capacity for experimental winemaking.

An exciting opportunity to expand and update the winery has recently presented itself. The building the research winery is currently housed in, Withycombe Hall, will soon undergo a $55 million, fully funded renovation. This renovation will increase available space for the winery from approximately 800 sq feet to over 2,000 sq feet. With the infrastructure needs taken care of, all we need to do is fill that space with equipment essential for enology research and teaching. This will include the addition of a large number of small capacity research fermenters and appropriately scaled processing equipment, as well as a winery laboratory fully equipped to conduct essential grape and wine analysis. Investment in the new winemaking facility will provide the OSU enology program with a state-of-the-art winery with outstanding capabilities comparable to our peers at other Universities. In addition, larger-scale equipment for teaching purposes will strengthen training of current students along with providing improved work force training through extension courses.

The Erath Family Foundation has generously kicked off our $531,000 fundraising campaign with a gift of $100,000 and a promise to fund another $100,000 if the remaining $331,000 is raised by December 2022. Sam Tannahill and Cheryl Francis also committed to a $100,000 gift for this opportunity leaving $231,000 left on our goal. There are opportunities at many different levels to contribute as we fundraise towards this goal. If you are interested in finding out more about the winery renovation, please contact James Osborne at or call 541-737-6494. He would be happy to talk with you about the plans for the winery and how this facility will have a profound impact on our ability to conduct enology and viticulture research and train the next generation of winemakers and viticulturists. You can also contact Amy Crumley (, the Senior Director of Development for the College of Agricultural Sciences, for more details on how to partner with us on this project.

Winery processing room.
Winery processing room.
Fermentation room with temperature-controlled tanks.
Fermentation room with plastic fermenters waiting to be filled with grapes.

Is Crop Estimation More Challenging in a Poor Fruit Set Year?

Every summer, vineyard staff spend days to weeks gathering data from field counts and weights to obtain harvest yield estimates. Getting as close to harvest estimates as possible is a primary goal of many producers. It is critical to make cluster thinning decisions to meet contract stipulations, purchase enough winery supplies, and ensure sufficient space is available at the winery for processing.

Over the past six or seven years, Oregon has had some of the highest and lowest wine grape yields. Vine yield was at a record low in 2020 due to poor climatic conditions during bloom. Crop estimation is challenging in a typical year, but it is especially challenging in poor fruit set years. This is due to the greater berry and cluster weight variability that requires more attention to detail in sample collection.

My lab has been working on ways to improve crop estimation for Pinot noir growers for a decade. This work was done to improve our current methods of estimating crop, and I have shared some of that work with the industry over the years (see Additional Information below). By using day count since bud break and bloom, and heat units (growing degree-days in Fahrenheit, GDD50) accumulated after those phenological stages, we found the berry development curve was tightly related to both day count and thermal time. These relationships allowed us to develop equations for cluster weight increase factors that would help growers estimate crop yields. I had many questions come in last year about how crop estimation methods would change due to the poor fruit set, so we took advantage of the year to understand how well our model works.

In 2020, we began monitoring berry development in a new project to quantify vine physiology and growth amongst different soil types. Within that project, we monitor berry development in the same way we did in our prior work from 2011-2016, starting with cluster sampling from ~20 days post-bloom and continuing until harvest. We collected 60 Pinot noir clusters once or twice weekly. Each cluster was measured for cluster weight, berry count, berry weight, rachis weight, rachis length, berry diameter, and seed hardness.

The findings. Berry size was smaller than normal, reaching an average size of 0.85 g (+0.2 g) at harvest (Figure 1). The typical Pinot noir berry is 1.0 g at harvest. There was also more variability in berry size with many “hens and chicks” throughout the entire season. Many small berries persisted with fewer larger berries. Clusters had substantial weight variation (Figure 2) due to varying berry count and berry size per cluster. By harvest, clusters ranged from 21 berries to as many as 186 berries, with the mean size of 81 berries per cluster. Mean cluster weight was under 80 g per cluster. A few veteran grape growers and winemakers comment that small berries do not double in size, so increase factors during lag phase crop estimation need to be lower than normal. We tested this question with our data in 2020, and we found that berries still double in size from lag to harvest (Figure 1). Cluster weight also increased as usual. Berry weight plateaued at 50-60 days post 50% bloom (lag phase), and this related to a cluster weight increase factor of 1.9 by harvest. This matched our prior study findings. The increase factor refers to the number used to multiply the mean cluster weight at sampling to obtain the final cluster weight for harvest. Berries reached their full size by 90 days post-bloom, about 5-10 days later than for berries in our model from 2011-2016.

Figure 1. Pinot noir berry mass increase based on day count post mid-bloom through harvest in 2020. Data points represent berry mass from 60 clusters, and error bars are standard deviations of the mean. The error bars are difficult to see given the small berry weight in the first six sample dates.
Figure 2. Pinot noir cluster mass increase based on day count post mid-bloom through harvest in 2020. Data points represent means from 60 clusters, and error bars are standard deviations of the mean.

When the cluster weight increase factors for 2020 were compared with the model, there was strong agreement at and after 30 days (Figure 3). The one sample date at 23 days post 50% bloom was higher than the model. However, the model matched precisely for 30 days post-bloom, and all other dates had agreement at 90% or better except for the two dates closest to harvest that underestimated cluster weight by 20-30%. Often the pre-harvest cluster weights may be variable due to berry desiccation with warm weather or extended hang time. These results show that the standard procedures for increase factor determination would apply for clusters with variable set.

Figure 3. Increase factors for cluster weights at day count post 50% bloom. The 2020 data points represent the increase factor mean of 60 clusters sampled at each date compared to the mean weight at harvest on 13 Sept 2020 (n=54 clusters). The calculated values are based on an increase factor model developed by Skinkis and McLaughlin (in progress).

How to estimate yield in poor set years. An essential part of crop estimation is obtaining a representative cluster sample that represents the vineyard spatially. Good vine and cluster counts are also needed. How the cluster sample is obtained is important in any year but particularly critical to do well in a poor set year where there is more variability than normal in berries per cluster and berry weight. To ensure the best crop estimates, employ sound sampling protocols to get cluster counts per vine and cluster weights from representative vines spatially distributed throughout the vineyard block and use appropriate increase factors. If you have inadequate sampling procedures (not enough clusters and not well distributed spatially), you can expect that your estimations will be even more variable and likely less accurate. I do not recommend a certain number of clusters, as it will vary by your vineyard size and level of variability. However, it should be a large enough sample to explain variability across the vineyard block accurately. Keep notes on your methods and be sure to train those who are sampling to follow those methods.

If you wish to use the OSU increase factor equations this year, contact Dr. Patty Skinkis, Professor and Viticulture Extension Specialist, OSU at

Additional Information

Skinkis, P. 2017. Crop Estimation: It’s all about timing and good data. Oregon Wine Research Institute Vine to Wine Newsletter, July 2017.

Skinkis, P. 2019. Improved Crop Estimation Methods for Oregon Pinot Noir. Oregon Wine Symposium, Portland, OR (seminar video).

Can Altering Canopy Shape Increase Productivity of Pinot noir: a new experiment at OSU’s Research Vineyard

Dr. R. Paul Schreiner, Research Plant Physiologist, USDA-ARS, Corvallis, OR

The newest block at Woodhall Research Vineyard is now six years old, and we will begin work in earnest next growing season to ask some fundamental production questions for Pinot noir. The key question is whether opening the top of a standard VSP training system (resulting in a Y-shaped canopy) will increase Pinot noir productivity without sacrificing quality (Figure 1). A second question is whether planting vines at a higher density impacts vine productivity or fruit quality. These questions are being addressed using a factorial experiment where two trellis treatments (traditional VSP & wide VSP) and two vine density treatments (3-foot and 6-foot in-row spacing) are applied in a randomized block design with five blocks. Each experimental plot has five continuous rows of vines about 100 feet long. Data will be collected from the middle three rows, allowing a border row of identical treatment on each side. Different crop levels will be applied to each of the trellis × density treatments by randomly assigning the north or south half of each plot to either low or high crop levels. The trellis and vine density treatments have been in place since 2015, and crop load will be manipulated for the first time next year. The vines were established using industry-standard practices (irrigation, fertilization, no crop in first two years, slowly increasing crop levels thereafter). In the last two years, vines were irrigated only twice each summer, when leaf water potential values reached about -1.4 MPa.

Why this design? Pinot noir producers in western Oregon use a VSP trellis system nearly exclusively where the shoots exist in a tight vertical plane that exposes only a small fraction of leaves to sunlight at midday when solar radiation is maximal. Opening the top of the trellis using a wide VSP system should increase net vine photosynthesis and the vine’s overall carbon budget, allowing more fruit to be produced per acre compared to a traditional VSP. This change can be implemented without removing the existing trellis, keeping costs low for this modification. A similar trellis design was shown to increase yield without compromising quality in Riesling vineyards (Reynolds et al. 1996). Pinot noir producers still thin crop to low levels, leaving 25-40% of their fruit on the vineyard floor. If opening up the canopy can allow Pinot noir producers to ripen more fruit per acre without negatively affecting quality, this approach can increase profits and sustainable production. Vine density per acre may also impact vine productivity or quality directly or by interacting with the altered trellis system. Still, such impacts cannot be predicted based on current knowledge. Since grafted grapevines cost about $5 each, reducing the number of plants needed per acre will significantly reduce establishment costs.

We have collected baseline data from the past five years. The block produced 2.2 US tons per acre in 2019 when the fruit was thinned to one cluster per shoot. Yield in 2020 was 2.5 tons per acre when no fruit thinning was applied due to low set in 2020. Thus far, yield has not been altered by the trellis or vine density treatments. However, vine vegetative growth based on pruning weights was altered for the first time in 2019. The high-density vines produced more shoot biomass in the wide VSP than the traditional VSP, but the low-density vines did not. Thus, the wide VSP appeared to capture more carbon than the traditional VSP in 2019, but only in high-density vines. We do not yet know if a similar response occurred in 2020 since pruning weights have not been obtained yet. Treatments have not altered yield parameters such as cluster weight and berry weight. Fruit composition based on must soluble solids, pH, titratable acids, and mineral nutrient concentrations has not been altered either. The application of different crop levels next year will result in a different yield, and this will begin to provide the true test of this experiment. I am excited to test these ideas on a large scale.

This research addresses improving vineyard production efficiency by altering the most common Pinot noir training system. If our hypothesis is correct, this research will improve Pinot noir wine grape growers’ profitability by increasing yield per acre, thus improving overall land and resource use efficiency.

Figure 1. Pinot noir in the Trellis Experiment at Woodhall Research Vineyard near midday on August 26, 2020. Top panel: Standard VSP. Bottom panel: Wide VSP. Note: larger shadow under Wide VSP vines.

Literature Cited

Reynolds AG, Wardle DA and Naylor AP. 1996. Impact of training system, vine spacing, and basal leaf removal on Riesling. Vine performance, berry composition, canopy microclimate, and vineyard labor requirements. Am J Enol Vitic 47:63-76.

Understanding the Economic Consequences of Smoke Events for the Oregon Wine Industry

James A. Sterns, Associate Professor, Applied Economics, OSU,

With genuine concerns for the loss of life and property during this time of still-burning wildfires, I am also challenged by questions about the economic consequences of these fires for Oregon’s wine industry. With most grapes still in the vineyard, the potential for significant loss of this year’s harvest weighs heavily on vineyard managers throughout the state. The short-run answer, unfortunately, is frustratingly vague. It’s like I am trapped in an NPR radio broadcast of Michael Feldman’s comedy quiz show, Whad’Ya Know? Each episode begins with the show’s namesake and host asking his live audience that question, to which the audience replies in unison, “Not much!” 

This article has two goals – first, summarize and provide links to the limited amount of information that is available; and second, to outline suggestions for creating the necessary records, data sets and documentation that will allow us to be better positioned to answer questions about the economic consequences of future smoke events.

First, what do we know? Several websites provide one-stop sourcing of available information. These include the Oregon Wine Board Wildfire Smoke Toolkit webpage and the University of California-Davis Wildfire and Smoke Exposure Resources website. Another comprehensive source of information is available from the Australian Wine Research Institute, which has been very active in recent years in supporting research on how smoke events can affect wine grapes and wine making.

These and other sources (reference links throughout this article) help frame questions about the overall consequences of smoke events. Still, in general, economic impacts are not addressed in any detailed manner. That type of substantive research-based information is still needed. As Associate Professor Elizabeth Tomasino and her colleagues reported in the August 2020 Vine to Wine issue, plans are in the works for grant-funded research on this topic. Their first step was to conduct a needs assessment with industry stakeholders, which included a shortlist of research topics related to smoke events’ economic impacts. As that research moves forward, one of the key constraints will be the availability of data from Pacific Northwest vineyards and wineries. Vineyard managers and wine makers can help resolve this ongoing challenge. Here are a few suggestions for how to help by documenting what is happening now and keeping records of this information for future reference.

Data needs for Estimating Economic Consequences in Vineyard and Wineries:

Weather & Air Quality Data – Keep track of your local smoke event data, which may be simple observational data (e.g., dates and duration of when you can smell smoke in your locality). Alternatively, some vineyards may have contracted with private farm management service providers, and in some instances, these providers have installed weather sensors. If this is the case, then the key is to archive in an easily accessible database detailed daily wind, temperature, humidity, and air quality readings as site- specific as possible. Understanding “trigger” levels of exposure that lead to smoke compounds in wines can become the basis for future vineyard management decision making. This starts with our ability to link vineyard conditions with test results of smoke contamination in wine crushes.

Variable, Fixed, and Total Costs – I often ask my students if it is ever a good idea to keep farming when losing money. I am trying to have them understand that a decision to go idle for a season or not harvest a crop will still have fixed costs to be paid. The choice to lose money is relative, so the better question a manager needs to ask is, “Which option will involve the least amount of loss?” In terms of this year’s grape harvest, can a vineyard manager hope to make enough from a harvested crop to cover all the variable costs associated with that harvest plus cover some of the fixed expenses that will always need to be paid? If so, then that’s the better choice. If the harvested crop’s value is less than the sum of variable costs of harvesting it, then obviously, it’s better not to harvest. In terms of data to be tracked, keeping detailed estimates of fixed and variable costs will not only help with decisions that must be made now, but also this financial information can be evaluated in a broader context for future smoke events. If enough vineyards track these costs, that data could be collected and aggregated anonymously, and then financial benchmarks could be established for making more informed decisions in years to come.

Dump, divert, or distill – A current recommendation for vineyard managers is to conduct small lot fermentations (a.k.a. micro-ferments or bucket-ferments) on grapes that have been exposed to smoke. Should results from these tests indicate that the grapes are unusable for wine, there are still managerial decisions to make. Once again, cost and price data are needed to inform this decision. Option one is to dump the grapes in the vineyard, either in the near future, or possibly waiting until pruning. Both options have vineyard management issues, but also economic ones. For example, what are the labor (and possibly machine costs if mechanically harvested) to dump the grapes now compared to potentially higher pruning labor time and costs if the grapes are left on the vine until then? Another possibility – grapes have nutritional value as animal feed. Could harvested grapes be sold to a neighboring livestock operation? And more importantly, what is the price the neighbor is willing to pay and is that price high enough to cover harvesting costs? A third option might be to use the grapes for distilling alcohol for the hand sanitizer market – a new market opportunity that has emerged during the COVID-19 pandemic. Again, the critical issue is the potential market value of the smoke-affected grapes for use as an input in this alternative product market.

Market responses, on inventory and current year crop – Another key area of data to track will be the market responses to these wildfire events. Two prices to track and record will be the value of any residual 2019 harvest in inventory, such as bulk wine. If this year’s smoke events leave wine makers shy on volume, will this lead to a price increase in the value of that inventory? If so, that is an economic consequence to document. Similarly, depending on the severity of this year’s smoke event, grapes grown in 2020 that are unaffected by smoke may see a price increase. Again, documenting any smoke-event driven shifts in prices will be critical for future work in estimating economic consequences.

Consumer responses, on-site and online – The COVID-19 pandemic complicates the analysis, but there still needs to be data collected about how winery customers are responding to the wildfires. On-site tasting room visits, which were already diminished by social distancing and other public health measures, will be further eroded by the wildfires. Collecting data on declines in visitations attributable to the wildfire will help future analyses. Similarly, tracking online sales, especially if consumers are shifting their buying habits, is also needed. Will consumers buy more of the current inventory in fear of future shortages? What are wine club members asking you during this time? Tracking their concerns and questions may be early indicators of how future sales of the 2020 vintage will be impacted. Aggregating these data, even if the overall effect on demand is negligible, will provide vital information for future analysis and forecasts of smoke events’ economic consequences.

Insurance Costs and Compensation – A final area of data that is needed concerns crop insurance. Data on insurance premiums paid by vineyards are needed. Even if a vineyard or winery opted not to purchase crop insurance, records of insurance companies’ quotes for proposed premiums are valuable for future analysis. Also needed are the costs of checking for potential, and if needed, proof of damage (e.g., costs of testing for smoke compounds and any other expenses of documenting the damage and certifying rejected sales). Finally, records about the amount of financial compensation received, should an insurance claim be paid will be important for future economic analysis. This should include any details about factors that affected the overall level of compensation (for example, some insurance policies will adjust claims and reduce the amount of payment if a vineyard is not harvested).

As we look to the future, we can anticipate a need for a better understanding of how wildfires and smoke events can affect the Oregon wine industry’s economic viability. Tracking and recording what is happening now, as decisions are being made in vineyards and wineries, will be vitally important sources of information for future research. With resiliency, the Oregon wine industry will emerge from the tragedies of this wildfire season. Let us work together to ensure that we can do better in the future by learning through our current adversities.

Oregon State University Receives Gift of the Artist

Ashland artist, Betty LaDuke, has generously gifted Oregon State University College of Agricultural Sciences three paintings to the Art About Agriculture program in commemoration of Dr. Porter Lombard, OSU Emeritus Researcher. Dr. Lombard’s contribution to the Oregon wine industry is immeasurable.

Dedicated to Porter Lombard for his pioneering work at Oregon State University in developing the Oregon grape industry, and beyond. And, for five decades of professional and personal friendship shared with my husband – Peter Westigard, an OSU Entomologist – and our families.” – Betty LaDuke, 2019

Betty LaDuke (née Bernstein) was born in 1933, The Bronx, New York City, to Jewish immigrant parents from the Ukrainian Soviet Socialist Republic and Poland. She grew up in an ethnically diverse neighborhood where early influences in her arts education included classes taught by distinguished African-American artists, Elizabeth Catlett and Charles White. College scholarships led LaDuke to study art at Denver University (1950), the Cleveland Art Institute (1951), and at the Instituto Allende in San Miguel, Mexico (1953- 1954). In Mexico, she explored the diversity and heritage of the region, as well as visited the studios of prominent Mexican muralists Diego Rivera, David Alfaro Siqueiros, and Rufino Tamayo. LaDuke founded her professional artist studio practice in Guanajuato, Mexico, and lived for one year with the indigenous Otomi people of the Ixmiquilpan Region where she painted murals that depicted Otomi heritage. In 1956, Betty LaDuke returned to the United States, where she met Sun Bear (Vincent LaDuke), gave birth to her daughter (activist community organizer Winona LaDuke (b. 1959)), and earned her Master’s Degree from Los Angeles State College (1963). In 1964, Betty and Winona moved to Ashland, OR where she taught in the Art Department at Southern Oregon University until retiring Professor of Art Emeritus in 1996. Betty LaDuke married Oregon State University Entomologist, Peter Hughes Westigard (1933–2011) in 1965, and had her son, Jason Westigard in 1970. In 1972, a sabbatical from teaching enabled LaDuke to spend a month in India sketching the people and their connection to nature, food production, and heritage; a trip that inspired annual travels throughout Asia, Africa, and Latin America that focused on sketching the experiences of indigenous women, their cultural heritage, and agricultural practices. LaDuke captured these experiences and sketches in numerous books, including Compañeras: Women, Art, & Social Change in Latin America (City Lights Books, 1985), Women Artists: Multi-Cultural Visions (Red Sea Press, 1992) and Africa: Women’s Art, Women’s Lives (Africa World Press, 1997). LaDuke’s work with Heifer International’s study tours from 2003 to 2009 culminated in the Dreaming Cows series of sixty-two artworks and the book, Dreaming Cows: The Paintings, Murals and Drawings of Betty LaDuke by Susan Jo Bumagin (Heifer International, 2009). LaDuke donated the series to Heifer International’s World Headquarters in Little Rock, Arkansas.

Betty LaDuke’s artworks can be found in many public and private collections throughout Oregon, including Coos Art Museum, Grants Pass Art Museum, Hallie Ford Museum of Art, Jordan Schnitzer Museum of Art, Pacific University, Portland Art Museum, Rogue Valley International Airport, Southern Oregon University, and the Art About Agriculture Permanent Collection (College of Agricultural Sciences, Oregon State University). LaDuke was the recipient of Oregon Arts Commission’s 1993 Governor’s Arts Award for individual contribution to Oregon culture, and the United States Society for Education Through Art 1996 Ziegfeld Award for distinguished leadership in arts education.

Bountiful Harvest
In 2010, Betty LaDuke was invited to observe and sketch the flower harvest at La Mera Gardens (Fry Family Farms) in Talent, Oregon. This experience served as an awakening to the marvel of local agricultural production and the people that make it possible.

Sketches from regular visits to the Fry Family Farms blossomed into numerous large paintings on shaped and routed plywood panels that celebrate the dignity and pride of farmworkers during all phases of agricultural production across a wide variety of produce. In 2012, the Rogue Valley International-Medford Airport acquired Celebrating Local Farms and Farmworkers, a selection of twenty-six panels, for permanent display. Betty LaDuke’s 2016 book, Bountiful Harvest: From Land to Table (White Cloud Press) shares her artworks and story along with stories from agricultural workers, orchard and vineyard owners, and the Ashland Food Cooperative.

Grape Planting
Betty LaDuke’s Grape Harvest, 2015, a triptych of acrylic paintings on shaped wood panels, was generously gifted to the College of Agricultural Sciences for permanent display within the Department of Horticulture in commemoration of Oregon State University Emeritus Researcher, Dr. Porter Lombard. Dr. Lombard’s contribution to the Oregon wine industry is immeasurable. The three panels comprising Grape Planting originated from sketches from Quail Run Vineyards, Roque Valley, Oregon, with guidance and support from the General Manager, Michael Moore. Grape Planting, 2015 was accepted into the Art About Agriculture Permanent Collection by the 2019 Art About Agriculture Advisory Council and co-sponsored by the Office of Institutional Diversity.

GIFT of the ARTIST, in commemoration of Dr. Porter Lombard, Emeritus Researcher in Horticulture at Southern Oregon Research and Extension Center (1962-1980) and Oregon State University, Corvallis (1980 to 1992)
Art About Agriculture 2019
Co-sponsored by the Office of Institutional Diversity

OSU provides online research and technical information for the Oregon wine industry

Dr. Patty Skinkis, Associate Professor and Viticulture Extension Specialist, Dept. of Horticulture, OSU

Members of the Oregon Wine Research Institute (OWRI) at Oregon State University work hard to provide you with current information on research that is in progress and provide access to research-based best management practices for vineyards and wineries. We have two online resources for your use, and they serve specific purposes:

The OWRI website
This website allows you to learn more about the research activities of OWRI. You will find research that is advancing wine industry knowledge or the fields of plant and food sciences. We provide newsletters, webinar videos, and articles about the research. Visit this site to learn how you can join our outreach events throughout the year.

The OSU Extension website
Oregon State University Extension faculty make technical information available for use by commercial growers and winemakers. This website is designed to help you troubleshoot vineyard or winery issues using unbiased, science-based information. To browse relevant content, click on “Crop Production” then “Wine Grapes” or “Food” then “Wine, Beer, Cider, and Spirits”.  Alternatively, you can use these direct links for wine grape and winery content.  

There are many agriculture Extension faculty throughout the state who provide online content in areas such as water, soils, pests, diseases, integrated pest management (IPM), marketing, and more, so be sure to use the site’s search feature. If you cannot find the information that you need on the OSU Extension website and want to consult with an Extension expert, use the website’s Ask an Expert form. Questions are routed to the appropriate Extension faculty (Skinkis, Osborne, Kaiser, Walton, etc.). Please note that this website is new, so more content will be added in the coming months.

Please visit these websites and give us feedback! Contact Denise L. Dewey with comments/feedback about the OWRI website. Contact Patty Skinkis (viticulture) or James Osborne (enology) for feedback on the OSU Extension website.

Vole Damage in Vineyards

Dr. Patty Skinkis, Associate Professor and Viticulture Extension Specialist, OSU 

I received a number of reports of vole damage in vineyards throughout the Willamette Valley this season. Evidence of their presence became visible in August with feeding damage to trunks (Figure 1) and within the canopy, including damage to shoots and rachises of grape clusters (Figure 2). Voles eat vegetation and typically feed on roots or the base of trunks. Voles do not typically cause issues until a population peak and/or environmental conditions allow for habitation. They may reach epidemic-level populations every ten to 12 years, but these population surges are not predictable and last for one year (Gunn et al. 2011). The Willamette Valley’s last reported vineyard infestation occurred in 2005, and some vineyards lost vines due to the damage.

Preventing and eradicating voles.  Our best suggestions to growers who have been observing vole presence in vineyards has been to encourage eradication. Trapping or baiting voles may not be practical on large acreage or advised with certain farming certifications. For example, zinc phosphide is not allowed in organic production. However, soil tillage or mowing may provide some level of prevention and control. Research in field crops show that tilling the soil is the most effective method of reducing vole populations (Jacob 2003), by disturbing their burrows and causing movement to other vegetated areas. Voles avoid bare ground, so tillage can prevent habitation altogether. In the Jacob (2003) study, they found voles disappeared altogether after disking to a depth of 19 inches. Mowing vegetation was found less effective than tillage, as the mulch from mowing allowed sufficient cover for the voles and did not encourage movement away from the cropped areas. Avoiding mulch layers or vegetation growth under-vine will prevent voles from inhabiting the areas near grapevine trunks and feeding on roots and trunks when food sources are limited.

Scouting for damage. Voles tend to feed on vine roots and at the base of trunks. Look for feeding damage at and just below the soil surface. Since the feeding typically occurs through the phloem and vascular cambium, the cell layers that lie between the phloem to the exterior and xylem to the interior, the vascular system is compromised. As a result, affected vines may turn color abruptly (yellow or red, Figure 3), as they have limited ability to move photosynthates (sugars) and mineral nutrients through the vines to the roots once the phloem and cambium are damaged. Roots are actively acquiring carbohydrates and mineral nutrients from the canopy during late season in preparation for the next year. Having this connection severed is a major issue.

Can anything be done to repair damaged vines? Vines with girdled trunks and root damage may not survive if the damage is done to the circumference of the vine. This is due to the lack of vascular cambium to grow new phloem tissue and “heal” the wound. The best thing to do at this time is flag vines with damage now and check back later in winter during pruning and early spring. If damage was only apparent in the canopy (rachises, berries, and shoots), vines may be able to be pruned to healthy tissue in winter. However, also be sure to flag these vines for follow-up.

Because voles do not hibernate, high populations this winter may pose a threat to vines if they continue feeding in areas where they were observed this season. It will be important to remove vegetation by way of tilling soil or removing mulch layers or vegetation under-vine to avoid any further damage.

Literature Cited

Gunn D, Hirnyck R, Shewmaker G, Takatori S, and Ellis L. 2011. Meadow voles and pocket gophers: Management in lawns, gardens, and cropland. University of Idaho, PNW 627.

Jacob J. 2003. Short-term effects of farming practices on populations of common voles. Ag Ecosyst Environ 95:321-325.


Figure 1. Vole damage to the base of a trunk on a mature grapevine. Photo courtesy of Ryan Wilkinson.


Figure 2. Feeding damage is apparent on the top of the grape cluster’s rachis (peduncle) and the lower portions of the shoot from which it originates. Photo courtesy of Ryan Wilkinson.


Figure 3. Vines with vole damage to the trunk show almost complete reddening of the canopy in Pinot noir vines. Photo courtesy of Ryan Wilkinson.


2016 Fall Viticulture and Enology Technical Newsletter Available

Our latest edition of the OWRI Technical Newsletter contains research updates, the latest Extension resources, and a comprehensive list of publications outlining research conducted by members of the Oregon Wine Research Institute at Oregon State University. Dr. Patty Skinkis, Viticulture Extension Specialist & Associate Professor, OSU opens the newsletter with a research update on the Statewide Crop Load Project. Dr. James Osborne, Extension Enologist & Associate Professor, OSU along with Dr. Michael Qian, Professor, OSU, provide valuable information on their research exploring the impact of elemental sulfur and nitrogen on volatile sulfur compounds. Lastly, Dr. Elizabeth Tomasino, Assistant Professor, OSU provides a summery of her research assessing brown marmoarted stink bug taint in wine.
Make sure to check out the Practical Guides and Resources section; we have some fantastic new resources, most of which are available online.
The newsletter is available here.

2015 Grape Day

The 2015 Grape Day program has been formalized and registration is now available. This event, designed to allow industry members the opportunity to hear about our latest research and meet with faculty members, is a cornerstone of OWRI programming and events. For over ten years, OSU viticulture and enology researchers have been communication research to industry in this format, and each year our programming offers something new and engaging. Please view our 2015 program here. As you can see, we have a captivating and relevant lineup of speakers again this year. We hope to see you on campus on March 31!


Danielle Gabriel
Communications and Outreach Manager

OWRI 2014 Year in Review


The OWRI presents our Year in Review video. It features a vine to wine picture compilation of research activities, outreach, and other happenings from our OWRI team members throughout 2014.

Please view it here.

Wishing you a safe and happy New Year!


Danielle Gabriel
Communications and Outreach Manager
Oregon Wine Research Institute