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MARCH NEWS When Grapevines Won't Die N Roots persist, carrying pathogens and pests in vineyard studies apa, Calif.—Considering how much cash and work growers spend to keep grapevines healthy, vines are surprisingly hard to kill. Dr. Brad Hanson, a weed-science spe- cialist at the University of California, Da- vis, discussed how to kill vine roots for pest and pathogen management and rede- velopment at a recent meeting of the Napa Viticultural Technology Group. Hanson reported that he tried various combinations of cutting off trunks, drilling holes, injecting or slashing with a hatchet fol- lowed by painting with glyphosate (Round- up), triclopyr (Garlon and Release)—al- though technically not registered for use on grapevines, they are on trees. He tried the EZ-ject, a device that uses an internal ham- mer to "shoot" insecticide into a vine. At a test plot, a grower also tried drill- ing a large hole and filling it with 2 ounces winesandvines.com Learn more: Search keywords "grapevines die." Wineries grow in number S acramento, Calif.—In spite of a weak economy, the number of wineries in North America continued to grow in 2011. The latest tally by WinesVines- DATA, the research arm of Wines & Vines magazine, identified 7,396 wineries now operating in the United States, an increase of 501 wineries, or 7% from a year ago. Canadian wineries now number 465, up 17%. The growth rate for wineries defied incidents of winery closings. Instead, it paralleled the increase in wine consump- tion in the United States, which last year became the world's biggest wine market. The six biggest states for wineries, in order, are: California, Washington, Oregon, New York, Virginia and Texas. —Wines & Vines staff Wines & Vines MARCH 2012 19 In a second phase of research, Hanson tried chemical treatments to kill a whole vineyard as part of a planned replanting effort to deprive pests and pathogens of a host and food source during renovation. Herbicides may have to be used for a In spite of herbicide treatments, many vines will resprout—albeit with stunted growth. of herbicide. The treatments proved inef- fective and inefficient. At best, less than 35% of the vine roots were killed; simply cutting the vines left almost 90% alive. MALA_Dir11.qxp 11/29/10 4:07 PM Page 1 number of years. "It's not as simple as fu- migating with Telone or methyl bromide," Hanson admitted. Most of the absorbed glyphosate, for example, remains in treat- ed leaves, and very little moves to the roots in most perennial plants. In all, Hanson tried 16 treatments while monitoring an untreated patch of vines. Treatments included various applications of glyphosate, triclopyr 3 amine and tric- lopyr ester, in some cases with oil to make it more persistent. Plants were treated in July, August and October 2011. The re- searchers plan to evaluate regrowth this year, including digging backhoe pits to evaluate the survival of the roots. —Paul Franson