Issue link: http://winesandvines.uberflip.com/i/718029
September 2016 WINES&VINES 65 WINE EAST GRAPEGROWING been cleaned via tissue culture. Site selection for mother blocks: New mother blocks must be isolated at least 100 feet from existing grape plantings and tested before planting for dagger nema- todes (the standard is less than 50 nematodes/250 cc of soil). Produc- tion blocks for certified vines will be subject to a buffer zone of 30 feet from existing blocks. Inspection: Mother blocks will be inspected by NYSDAM horti- cultural inspectors. They will sample one of every four vines (25%) in the mother blocks annu- ally, and each vine will be tested every four years. Testing by NYS- DAM inspectors will establish a chain of custody, with sample test results linked to individual vines. Testing methods: Each sam- ple will be tested for the presence of tomato ringspot virus, tobacco ringspot virus, grapevine fanleaf virus, five grapevine leafroll-asso- ciated viruses and grapevine red blotch-associated virus. Labora- tory tests will be a combination of ELISA and DNA testing, as appro- priate, under supervision of the virologist at the NYS Agricultural Experiment Station. Removal in the event of positive tests: If a mother block vine tests positive, the protocol calls for removal of all vines within 5 meters for a mealybug- vectored virus, and 10 meters for a nematode-vectored virus. New York-certified labeling: Vines propagated from certified mother block accessions will be allowed to carry a special label authorized by the NYSDAM. This testing and inspection program, with each mother vine tested every four years, will start in 2016; when implemented, it will be among the most rigorous in the United States. Nursery participation The three New York nurseries— Double A Vineyard, Grafted Grape- vine Nursery and Hermann J. Wiemer Vineyard—have started establishing mother blocks for pro- ducing certified scion and root- stock material (see table "Nursery Plans for Certified Mother Blocks in New York"). While plans vary, all started establishing new blocks in 2014 and 2015, and they antici- pate eventual plantings of 20-40 acres, producing both certified rootstock and scion material. Fin- ished vines are expected in limited quantities starting in 2018, with production kicking in around 2020, when the new mother blocks are mature enough to produce sig- nificant budwood. This testing and inspection program, with each mother vine tested every four years, will start in 2016 and, when implemented, will be among the most rigorous in the United States. How much value do certified vines add? Many economic analy- ses (Yeh et al., 2014) propose an economic lifespan of 25 years for new vineyards. Viral infections can reduce yield and/or quality, limit- ing the productivity of the vine- yard. Over the life of the vineyard, what are the consequences of not using certified vines on the net rev- enue of the vineyard? A study of leafroll virus in the Finger Lakes (Gomez et al. 2010) used net pres- ent value analysis to estimate a range of $9,693 to $16,014 lower revenue per acre, based on as- sumptions about what percentage of vines were infected at planting and how fast the virus spread. Nurseries will incur added ex- penses associated with the testing and certification program and will likely have to charge a premium for New York-certified vines. The ques- tion is, how much of a price pre- mium could nurseries charge and still provide net value to growers? Economists Shady Atallah and Miguel Gomez used Net Present Value (NPV) analysis to compare the risk of using propagation mate- rial collected from commercial vine- yards (formerly a common practice in New York) with the practice of planting with certified, virus-tested material. Using information about leafroll prevalence in commercial blocks in the Finger Lakes (60% of vineyard blocks with some leafroll; 5% of vines infected with leafroll, on average), Atallah estimated that the value of certified material sup- ported a price premium of $1.68 per vine over the $3.50 base vine price. In other words, if uncertified vines cost $3.50, growers can afford to pay up to $5.18 per vine and have higher net returns over the life of the vineyard. Clean plants and the future Viral infections impose hidden costs on grape producers in terms of yield and quality reduc- tions. Past propagation practices, such as collecting budwood from a variety of commercial sites, have resulted in widespread dis- semination of infected vines— a n d s u b s e q u e n t s p r e a d b y vectors can, over time, greatly increase the number of vines in- fected in commercial blocks. In- creasing the availability and use of certified, virus-tested vines GRAPEVINE LEAFROLL INCIDENCE IN NEW YORK, VIRGINIA AND MICHIGAN State Vineyards Sampled No. of Varieties Tested Vineyards With at Least One Infected Sample No. of Samples Samples testing positive New York 1 95 16 66% 1,900 26% Virginia 2 77 17 65% 1,300 33% Michigan 3 47 — 68% 394 28% 1 Includes GLRaV-1, GLRaV-2, and GLRaV-3. Twenty samples collected per vineyard (Martinson et al., 2007). 2 Includes GLRaV-2, GLRaV-3, and Grapevine fleck virus (GFkV) (Jones, Naidu and Nita, 2015). 3 Includes GLRaV-1, GLRaV-2, GLRaV-3, and GLRaV-4 through GLRaV 9 (A. Schilder, personal communication).