Last month\u2019s discovery in Walla Walla Valley of grape phylloxera, a microscopic, aphid-like louse that destroyed much of the world\u2019s wine grape vines in the late 19th century, reverberated quickly across the Washington State wine industry.\r\n\r\nFirst up. What does the presence of phylloxera in Washington State mean for the wine-consuming public? Not much.\r\n\r\n\u201cThis truly does not have an impact to the consumer, as it does not affect wine quality,\u201d says Steve Warner, president of Washington State Wine.\r\n\r\nRather, phylloxera affects grapevine productivity. As they feed, the insects damage grapevine roots. Over time, this reduces vine vigor, making it uneconomical to continue growing fruit and forcing replanting. Phylloxera can also inhabit leaves, but this form of the insect has not yet been found in Washington.\r\n\r\nWarner notes that Washington is far from alone in facing this issue.\r\n\r\n\u201cThe vast majority of the world\u2019s wine regions have successfully managed their vineyards despite the presence of phylloxera, and we will too,\u201d he says.\r\n\r\nIndeed, wine regions throughout Europe, California, Oregon and elsewhere have all combated the insect at some point.\r\n\r\n\u201cWe suspect that [phylloxera] had been in that one spot for quite some time, but it hadn\u2019t moved, which is very good news.\u201d \u2014Chris Figgins, president/director of winemaking, Figgins Family Wine Estates\r\n\r\nDue to phylloxera\u2019s effect on vine vigor, the vast majority of the world\u2019s wine grapes are now grown on phylloxera-resistant rootstock. This means combining European grape vine varieties we are all familiar with (the species Vitis vinifera) with rootstock from various North American vine species that have natural resistance to the pest.\r\n\r\nWashington State, however, has long prided itself as one of the world\u2019s few wine regions nearly 100% planted on vinifera rootstock. It\u2019s so much a part of the culture that one of the state\u2019s founding wineries, Chateau Ste. Michelle, lists \u201c100% vinifera rootstock\u201d on some of its wine labels. Being \u201cown-rooted\u201d has become engrained in Washington\u2019s identity.\r\n\r\n\r\nHow did phylloxera find its way to Washington?\r\nWhile finding phylloxera in Walla Walla Valley came as a shock to some, the insect\u2019s presence is by no means new to the state. Phylloxera has been in Washington since at least 1910, when it was first found in the city of Kennewick.\r\n\r\nThe Washington State Department of Agriculture has analyzed 100 sites annually in recent years to track phylloxera. Typically, the number of cases identified has been extremely small.\r\n\r\nWhy has phylloxera\u2019s growth been limited in Washington to date, while the pest has proliferated everywhere else?\r\n\r\n\u201cPhylloxera itself, under Washington soils and environmental conditions, it survives, but it doesn\u2019t thrive,\u201d says Michelle Moyer, associate professor in horticulture and viticulture extension specialist at Washington State University.\r\n\r\nMost of eastern Washington, where the vast majority of the state\u2019s wine grape vines are planted, have soils that are quite sandy. That limits or can even eliminate phylloxera\u2019s ability to reproduce. Due to the high sand content, the belief was that phylloxera couldn\u2019t build numbers that would cause problems.\r\n\r\n\u201cThat\u2019s true for most of Washington,\u201d says Katie Buckley, entomologist at Washington State Department of Agriculture. \u201cUnfortunately, that\u2019s not true for all of Washington.\u201d\r\n\r\nWhy are people finding phylloxera now?\r\n\r\n\u201cThe biggest reason people are finding it is that they are actually looking for it,\u201d says Moyer.\r\n\r\n\r\nThe Walla Walla Valley and beyond\r\nChris Figgins, president/director of winemaking at Figgins Family Wine Estates, which includes Walla Walla Valley\u2019s first commercial winery, Leonetti Cellar, explains what happened in the valley this way.\r\n\r\n\u201cThere\u2019s this one block [in part of the valley] that for years had a weak spot in it,\u201d he says. \u201cWe just couldn\u2019t seem to get the vigor in it. Our entomologist started doing the math and started digging, and, sure as hell, she found phylloxera.\u201d\r\n\r\nFiggins says it\u2019s unlikely the insect\u2019s presence there is new.\r\n\r\n\u201cWe suspect that it had been in that one spot for quite some time, but it hadn\u2019t moved, which is very good news,\u201d he says.\r\n\r\nAfter quickly meeting with partners that own vineyards near the identified area, there was a subsequent gathering of the larger Walla Walla industry to discuss the issue. More investigation led to more findings of the pest.\r\n\r\n\u201cThere are going to be growers here that are going to have to slowly replace their vineyards with grafted rootstock. But I suspect there will be others that will never have a problem.\u201d \u2014Katie Buckley, entomologist, Washington State Department of Agriculture\r\n\r\nWhile not an issue that affects consumers, these new detections of phylloxera do have potential significance for the state\u2019s 350+ grape growers. While Walla Walla Valley has received the brunt of attention by speaking up publicly about its phylloxera discovery, this is an issue likely for other growing regions in the state as well.\r\n\r\n\u201cI can assure you, it\u2019s not isolated to Walla Walla,\u201d says one grower, on the condition of anonymity. \u201cIt\u2019s in other areas. You can see it if you know what you\u2019re looking for.\u201d\r\n\r\nStill, the current thinking is that phylloxera\u2019s presence in the state is limited.\r\n\r\n\u201cWe estimate that the number of affected vineyards in the state of Washington is still extremely low,\u201d says Warner.\r\n\r\nTrying to keep it that way will involve numerous state and local agencies.\r\n\r\n\u201cWe will work with growers and researchers to determine the best long-term management strategy,\u201d says Warner.\r\n\r\nAt present, the Washington Winegrowers Association has re-emphasized practices to limit the spread of phylloxera and other pests.\r\n\r\n\u201cWe\u2019ve been reminding everyone about best practices, sanitation and particularly restricting soil movement,\u201d says Vicky Scharlau, the group\u2019s executive director. It will seek to fund a comprehensive survey of the state to look for the insect.\r\n\r\n\r\nThe phylloxera upside\r\nThe good news for Washington grape growers and wine lovers? The problem that phylloxera presents has already been solved throughout the world. Long-term, affected areas will be replanted to phylloxera-resistant rootstock, just like everywhere else.\r\n\r\n\u201cYou play that game of the time until a vineyard is no longer economically profitable, then you replant,\u201d says Moyer. \u201cIf an area is not affected, you don\u2019t have to switch to rootstock.\u201d\r\n\r\nIn fact, a small number of growers have already planted on rootstock in anticipation that this day might come.\r\n\r\nIt\u2019s likely that vineyard practices will shift as well. In recent years, some growers have limited the use of herbicides in favor of mechanical weeding. That might change.\r\n\r\n\u201cThere\u2019s no better way to spread [phylloxera] than dragging a weed badger through a vineyard,\u201d Figgins says. \u201cSo we\u2019ll need to rethink that.\u201d Equipment will have to be sterilized before being shared across sites.\r\n\r\nA number of growers that intended to plant vineyards next year have said that they\u2019ll wait another year to plant on rootstock. However, given the expected slow growth of phylloxera in the state, growers anticipate there\u2019s plenty of time to plan and perhaps eventually replant.\r\n\r\n\u201cTo me, this is a 20- to 40-year transition that\u2019s going to happen,\u201d says Figgins. \u201cThis is a long-term situation. It\u2019s not a qualitative impact. It\u2019s manageable.\u201d\r\n\r\nBuckley agrees. \u201cThere are going to be growers here that are going to have to slowly replace their vineyards with grafted rootstock,\u201d she says. \u201cBut I suspect there will be others that will never have a problem.\u201d\r\n\r\n\u201cWe have some 40-year-old vines. I\u2019d like to see them at the end of my career be 80, but I don\u2019t know if that\u2019s going to happen now." \u2014Chris Figgins\r\n\r\nReplanting could even have a silver lining. Rootstock is used all over the world to manage other pests, not just phylloxera. One such pest, nematodes, affects some Washington vineyards. Different rootstocks are also used to control issues like vigor and manage poor soil conditions.\r\n\r\n\u201cMaybe this is the chance to get people to reconsider the value of rootstocks in Washington\u2019s production and the added tool it can give a viticulturalist,\u201d says Moyer.\r\n\r\nStill, it\u2019s hard not to feel some sense of loss.\r\n\r\n\u201cI won\u2019t pretend that I didn\u2019t wish we were own-rooted forever,\u201d says Figgins. \u201cWe have some 40-year-old vines. I\u2019d like to see them at the end of my career be 80, but I don\u2019t know if that\u2019s going to happen now.\r\n\r\n\u201cWe\u2019re going to do our darnedest, especially with some of our old blocks, to keep them clean as long as possible. We\u2019ll gradually have to replant things. If any block gets below an economic threshold, then it will have to happen.\u201d\r\n\r\nSean P. Sullivan is a contributing editor at Wine Enthusiast and is also an educational consultant for Washington State Wine.