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!

Cheers,

Danielle Gabriel
Communications and Outreach Manager
OWRI

OWRI 2014 Year in Review

Greetings,

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!

Cheers,

Danielle Gabriel
Communications and Outreach Manager
Oregon Wine Research Institute

Oregon Wine Industry Symposium Spanish Sessions

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.

Welcome to the Fall 2013 Newsletter

The OWRI Team

This edition includes articles from various OWRI team members ranging from viticulture to enology and sensory. The OWRI’s Extension Specialists contributed articles focused on timely topics related to the 2013 vintage.  Dr. James Osborne, OSU Enology Extension Specialist, provides an article on methods by which to reduce the impacts of off odors caused by sulfur compounds post-fermentation.  On the viticulture side, Dr. Patty Skinkis, OSU Viticulture Extension Specialist, summarizes research comparing manual and mechanized leaf removal and impacts for vineyard management in Oregon. Dr. Paul Schreiner and Dr. Inga Zasada, USDA-ARS researchers, provide a comprehensive summary of current and past research conducted on ring nematode in western Oregon vineyards. Dr. Laurent Deluc, OSU Assistant Professor, provides a general summary of genomic research into berry ripening synchronization and future applications for the winegrape industry. Dr. Elizabeth Tomasino, OSU Assistant Professor, presents a brief summary of her latest research in sensory analysis with an update on the OWRI Sensory Panel. This edition also includes a news brief on David Adelsheim, who was inducted into the College of Agricultural Sciences 2013 Hall of Fame, and concludes with recent happenings from the OWRI interim director, Dr. Bill Boggess.  As always, be sure to explore the list of various publications and resources available for you to read and expand your knowledge in viticulture and enology. Finally, consult the end of the newsletter for upcoming events, including the 2014 Grape Day where we will feature research of the OWRI faculty!