Issue link: http://winesandvines.uberflip.com/i/74666
GRAPE GRO WING Is there a reason to switch? R ight now, there seems to be no good reason for Washington growers to switch to grafted rootstocks. Indeed, for economic reasons it is better to stay with own-rooted plants wherever possible. "When we have a freak cold snap, and eastern Washington sees these periodi- cally, vines can die to the ground," said WSU viticulturist Markus Keller. "Grafted vines would need to be regrafted because the graft point sits above the ground, while own-rooted vines will likely recover on their own." Regrafting is expensive, and grafted vines create higher initial startup costs be- cause they are more expensive for nurseries to produce. Keller cautioned, however, that eventual- ly there would likely be cause for Washing- ton growers to move toward grafted vines. SpecTrellising_July10.qxp 5/13/10 9:25 AM Page 1 "Nematodes build up in the soil over time," he said, "so increasing numbers of second- or third-generation vineyard plantings will likely need to be on grafted vines." As for why Washington has, for the most part, not been scourged by phylloxera, the sap-sucking insect that plagues nearly ev- ery other growing region, Keller said no one knows. "Some think it is our cold winters, but…Germany, Switzerland and Canada have problems with phylloxera. It may be that our dry soils make it hard for the insect to spread." For that Australia offers a cautionary tale, he said, as trucks and mechanical har- vesters are likely the cause of the spread in the dry soils there. "A few insect eggs could have been caught in tractor tires and spread from one location to another." B.C. References 1. M. Keller, L. Mills and J. Harbertson, "Rootstock Effects on Deficit-Irrigated Winegrapes in a Dry Climate: Vigor, Yield Formation, and Fruit Ripening." ajevonline.org/content/63/1/29.full. 2. J. Harbertson and M. Keller, "Root- stock Effects on Deficit-Irrigated Wine- grapes in a Dry Climate: Grape and Wine Composition." ajevonline.org/ content/63/1/40.abstract. Dr. Keller's crew grafts vines. The vineyard, years and contributed essential expertise to the project. The WSU Agricultural Research Center, the Northwest Center for Small Fruits Research and the Wash- ington Wine Advisory Committee helped fund it, while donations of plant material came from Ste. Michelle Wine Estates and Inland Desert Nursery; Quiedan Co. donated trellis materials. "This type of experiment has never been done before on this scale and with this many variables," Harbertson said. "It was huge and complex. The methods and results truly reflect Washington's unique conditions." 50 WINES & VINES AUGUST 2012