Vineyard and Winery Information Series: VITICULTURE NOTES ........................ Vol. 25 No. 2, March - April, 2010 Tony K. Wolf, Viticulture Extension Specialist, AHS Jr. Agricultural Research and Extension Center, Winchester, Virginia [email protected] http://www.arec.vaes.vt.edu/alson-h-smith/grapes/viticulture/index.html I. Current situation .................................................................................. 1 II. Question from the field: replanting decisions ...................................... 2 III. Climbing cutworm update ..................................................................... 4 IV. New pesticides listed in 2010 PMG ...................................................... 5 V. Early season grape disease management .......................................... 7 VI. Upcoming meetings ............................................................................. 8 I. Current situation: Pest Management Guide (PMG) can be downloaded at: New Viticulture website: Cooperative http://pubs.ext.vt.edu/456/456-017/Section- Extension and Virginia Agricultural 3_Grapes-2.pdf Experiment Station websites were upgraded The pesticide recommendations are annually to a new server and hosting system which prepared by pest management specialists required a revision of content and change of with grape expertise at Virginia Tech, and URL. The new viticulture website is: form the basis of our grape pest http://www.arec.vaes.vt.edu/alson-h- management program. Pesticide smith/grapes/index.html recommendations augment cultural control Follow the links from here to “Viticulture” and practices, including integrated pest “Extension and Outreach” to find most of the management of arthropod pests and good materials that were posted to my old canopy management techniques to set the website. Additional content will be added stage for effective disease control. Detailed periodically. Several readers have inquired disease management recommendations can about where old Viticulture Notes editions be found in past issues of Viticulture Notes, are maintained. They are still available; in the Compendium of Grape Diseases however, I have lost the cumulative index (http://www.shopapspress.org/40888.html), with hyperlinks and will have to rebuild that at Dr. Nita’s (our grape pathologist) website as time allows. The URL for the archived (http://www.arec.vaes.vt.edu/alson-h- Viticulture Notes newsletters is: smith/grapes/pathology/index.html) and by http://sites.ext.vt.edu/newsletter- attending regional vineyard meetings, a archive/viticulture/ number of which are listed in this newsletter. 2010 Grape Pest Management Guides: Meet Virginia Tech’s new Dean of the Virginia Cooperative Extension’s 2010 Grape College of Agriculture and Life Sciences: Dr. Viticulture Notes: March - April 2010: page 2 Alan Grant has been dean of Virginia Tech’s A first step would be to inventory the College of Agriculture and Life Sciences vineyard block and record the number of since October 1, 2009. Dr. Grant will be missing or diseased vines (for regular VN visiting with interested industry members and readers, this was recommended in a the public in a series of 7 town-hall meetings “Harvest update” that I issued last starting in early March (go to this link), one of September, when disease was easy to spot which will be here at the AHS AREC (April and flag). “Disease” would be easier to 29th). The public is invited to these meetings assess when a canopy is present, but an and I would encourage you to attend and assessment of crown gall, weak or otherwise meet dean Grant and discuss your ideas of obviously compromised vines can be helpful how Virginia Tech and the College can best even if done prior to budbreak. If the serve the grape and wine industry. assessment can wait until the growing season, pay attention to symptoms that might be indicative of disease. For example, II. Question from the field: I’m exploring we have recently focused some of the the option of purchasing an existing vineyard industry meetings (VA Vineyards which has a 5-acre block of mature (about Association) on recognition and 20 years old) Chardonnay vines of uncertain consequences of diseases such as leafroll health and which is missing a number of virus, esca, Eutypa and Botryosphaeria vines. What are the pros and cons of canker. It’s important at this stage of vine replanting this entire block vs. filling in the assessment to also differentiate the missing vines with replants? What would “manageable” problems from those that replanting cost? What is the best procedure cannot be corrected. For example, leafroll to replant, and how long will it take for the virus symptoms might be confused with replanted vines to be in full production? certain nutritional deficiencies, especially phosphorus deficiency. The nutrient Answers: This is a timely question, but there deficiency can be corrected, whereas the is no one “best procedure” for replanting. leafroll disease condition cannot; leafroll- There are many vineyards that we see infected vines should be removed/replanted. around the state whose vines have suffered If leafroll is prevalent in the vineyard block, from various diseases, abiotic stress, or the entire vineyard block should be removed simply mechanical damage, and are in need and replanted. The canker diseases can be either of completely replanting or selectively managed to some extent with aggressive replanting. While some winemakers extol the pruning, protection of pruning wounds on all merits of “old vine” wines, in cases with good vines, and destruction of pruned vine parts cause, getting a vineyard population of vines as though burning or burial outside the to a uniformly “old” age of 25, 30, or more vineyard. years old – and in good health – is a difficult feat in our mid-Atlantic climate. There was a At the same time that you inventory vine time when winter injury would often reset this health and/or record missing vines, note the clock for us and cause, at minimum, a condition of the trellis hardware. Are posts retraining of new trunks if not replanting of loosely set, rotted or splitting? Are staples entire vines. Winter injury has not been a easily pulled out? Is the trellis wire corroded recent, widespread phenomenon in Virginia (look at where it passes through staples), and we are seeing more vineyards now rusted, or spliced from previous breakage? reaching a ripe old age of 20 or more years. Are the in-line tensioners in serviceable Unfortunately, we are also finding ample condition? Granted, this is a judgment call, evidence of trunk/cordon pathogens such as but the condition of the trellis, combined with Eutypa and Botryosphaeria canker, Esca an assessment on replanting needs will help (black measles), and certain virus diseases determine whether to replant missing vines (getting old is hellish…). or replace the entire vineyard. We figure the life of a normally maintained trellis with Viticulture Notes: March - April 2010: page 3 pressure-treated posts to be no more than replants? It’s a classic, academic answer: it about 30 years. If the vineyard is depends. It depends on condition of the approaching that age, and there are other vines, condition of the trellis, soil condition, factors that weigh towards entirely replanting vineyard design, etc. as I’ve outlined above. the vineyard, then it might also be a good If more than about 30% of the vines are idea to replace the trellis at the same time. missing or diseased, the trellis is in disrepair, As we’ll see, there can be advantages, the soil needs substantive remediation and including new opportunities, in installing a the vineyard rows or vine spacing are too new trellis along with new vines. generous, I’d say that a complete reinstallation is in order. That’s an extreme One other consideration on the vines: What option. At the other extreme is to do nothing are the current variety, clone and rootstock? and continue farming the existing planting What was planted 20 years ago may not be with whatever deficiencies it has. There the best choice today. You indicated that the should be some logic to help arrive at variety is Chardonnay. Chardonnay is still alternative options in between those two the state’s number one variety in terms of extremes, but the considerations to do so will quantity for good reason – it is adaptable to vary with individuals’ investment time a wide range of growing conditions and it’s horizon, wine quality benchmarks and goals, generally well recognized by winery traffic. available financing, and other unique factors. Varietal clone is more subjective and I would not condemn an otherwise good planting of If the trellis is in good repair and the existing Chardonnay simply because it’s planted to a row width is utilizing vineyard space clone that might not be a preferred clone reasonably efficiently, you could go the route today. So-called “high yielding” clones, like of simply replanting to fill missing spaces. high-yielding varieties, can make great wines Ideally, this would be done every few years, if the time and management is used to keep or as necessary in the life of a vineyard, to the crop in balance with functional leaf area. keep the vineyard at maximum productivity. Replanting directly into old vine locations in Another consideration at this point is the the row can occasionally lead to poor growth condition of the site and the design of the of the replant. The reasons for poor growth vineyard. Note the row spacing. Is row width are due to multiple factors, most of which are (canopy to canopy) much greater than considered to be of a soil-borne, biological anticipated canopy height (about 5’ for origin, such as a build –up of parasitic vertically shoot-positioned vines)? nematodes. Moving the new vine in the row Vineyards planted in the early to mid-eighties a foot or so, or planting the replant with bulk were often designed with very wide rows (12’ soil from another location can help avoid was common) to accommodate the only retarded vine growth.