Issue link: http://winesandvines.uberflip.com/i/573907
68 P R A C T I C A L W I N E R Y & V I N E YA R D October 2015 S M A R T V I T I C U L T U R E Multi-trunking for vine longevity By Lucie Morton Because U.S. grapegrowers with vineyards east of the Rocky Mountains can experi- ence very cold winter temperatures, the practice of maintaining more than a sin- gle trunk from the start is common. It is especially critical for those growing Vitis vinifera varieties as opposed to traditional native American vines and hybrids with greater cold tolerance. Today, as the relatively young wine industry and its vines mature, it has become clear that this practice will also prolong the life of a vineyard by renewing aging and diseased vascular systems. As Richard Smart discusses—and a search of the International Council of Grapevine Trunk Diseases (ICGTD) web - site icgtd.ucr.edu will confirm—there are many different fungi involved in vine decline caused by xylem plugging and wood dessication. These fungi can coexist with vines for many years without being particularly detrimental, or they can lead to problems with vines of all ages starting with very young plants in the nursery. As with any disease complex, climate has a huge influence on which symptoms and associated fungi are more prevalent and how much their presence will affect vine health. Th e eastern United States includes Florida in the south stretching to Ontario, Canada, in the north and west - ward to the Rockies. Farm wineries in this region are gener- ally small in size. For example, the two largest vineyards in Virginia hover around 200 acres, but many are much smaller. Most vineyards are far apart geographi- cally and in sites that have not had vine- yards previously. Therefore, wind-blown spores from neighboring vineyards are not a big problem. Fungi introduced by plant material from elsewhere may or may not survive in this new environment. My photo of a circa 25-year-old Cabernet Sauvignon/5BB vine planted in the mid- 1970s in Virginia shows the progression of Esca disease three different-aged trunks on the same vine. I took the photo in about 1999 in a Virginia vineyard with 20-plus year old Cabernet Sauvignon vines that were being pulled out. Multiple trunking was done here as a hedge against winter damage. These trunks are 22, 15 and seven years old. Petri disease was very much in the forefront of controversy then (1998 being the founding of the ICGTD and 1999 being the first inter - national meeting in Siena), and by then it had been linked to Esca and vine decline. This vine has all the symptoms of clas- sical Esca disease where there is black goo staining in young xylem tissue, brown wood in older wood, and the classic white rot caused when basidiomycetes finish off what ascomycetes starts. Occasionally, there will be tell-tale "tiger-stripe" foliar symptoms perhaps due to Botryosphaeira fungi in the mix with the Phaeomoniellas and Phaeoacremoniums. To protect one's investment from losing economic viability over time, one should consider a combination of close vine spac - ing, cane pruning, multiple trunking and/ or trunk renewal. Like grafting, it brings along some extra cost and cultural incon- venience that should be factored in with an increase in productive lifespan. SELL TO MORE GROWERS The Wines & Vines Grower Online Marketing System (GOMS) enables users to create and save highly customized grower searches, and export results into advanced report types, data exports and mailing labels. (866) 453-9701 • winesandvines.com/OMS SELECT RECORDS BASED ON: SELECT RECORDS BASED ON: SELECT RECORDS BASED ON: region varietals acreage grape sales new vineyard