Issue link: http://winesandvines.uberflip.com/i/62507
GRAPE GRO WING Foundation Plant Services Process for Propogating Clean Vines, Part II 4 5 6 4. Symptoms in the indicator plants are observed for two years. 5. PCR tests are done in the lab for more than 18 viruses and pathogens. 6. Grape meristems are cut in a sterile airflow hood. How good are our laboratory techniques for determining the presence of leafroll viruses? The technology available is very good and continues to improve, but it is possible we haven't identified all causal agents. If I am making good wine from a heavily leafroll-infected vineyard, should I worry? This is a difficult question to answer. Grow- ers and winemakers sometimes have emo- tional attachments to old blocks they can coax to produce a few cases of interesting wine. If the block is heavily infected with leafroll virus and vectors are present, it can serve as a potent inoculum source to in- fect other blocks around it. This should be taken into serious consideration if leafroll virus appears to be an increasing problem in a production area adjacent to an old, leafroll virus-infected block. If I have an old clone that I really like, but it is infected, can it be cleaned up? Yes. It will be expensive and may take as long as four years. It first must be grown on its own roots, grown in a heat chamber, propagated from a shoot tip meristem in agar media using tissue culture techniques and then grown out in soil and certified as virus-free with various lab techniques. Do we have a chance to get ahead of leafroll viruses, or are we doomed? The response by researchers and industry to wage a robust research program on the control and management of leafroll virus has been impressive. While definitely in the "work in progress" phase, the multipronged approach of studying the viruses, vectors and epidemiology is a very potent strategy. There will be additional work done by economists and sociologists to better un- derstand producers' attitudes toward the need to adopt new technologies and ap- proaches to managing leafroll in their vine- yards. Finally, within a few years we will have "best practices" to deal with prevent- ing the spread of this troublesome disease that may involve quarantines, IPM control, new detection techniques, clean plant mate- rial and good old common sense. Glenn McGourty would like to thank Univer- sity of California scientists Deborah Golino, Kent Daane and Andy Walker for providing informa- tion used in this article. McGourty is the UC Co- operative Extension winegrowing and plant sci- ence advisor for Lake and Mendocino counties. He also tends a 1-acre vineyard of the aromatic Italian winegrape variety Arneis on his property along the Russian River near Ukiah, Calif. featuring keynote speaker Karen Ross, Secretary of CDFA November 14-15, 2011 Paso Robles Event Center Paso Robles, CA www.sustainableagexpo.org Presented by the Central Coast Vineyard Team 835 12th Street, Ste. 204 • Paso Robles, CA 93446 www.vineyardteam.org • 805.369.2288 Wines & Vines OCTOBeR 2011 63