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.
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.
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 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!
Communications and Outreach Manager
The Oregon Wine Board will be sponsoring the annual Oregon Wine Industry Symposium in Portland on February 25 & 26. This event is designed to provide the wine industry with relevant, up-to-date information, and techniques for grape growers and winemakers alike. This event gathers people from Oregon’s various wine regions together to network and share ideas to improve their businesses.
This year, the Symposium is offering Spanish sessions. Both days, all Viticulture and General Sessions will be translated in real time by professionals. Attendees will get a full Symposium experience as well as a deeper, richer educational opportunity.
To view a flyer about the Spanish session, please click here.