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Bugged Out


Kim Marcus
Posted: February 3, 2000


Bugged Out
By Kim Marcus, assistant managing editor

Good times are the order of the day in the California wine industry, what with Americans drinking more wine, $100 a bottle becoming the norm for top Cabernet Sauvignons, and a growing sense of recognition that the state's wines can compete with the best in the world. As a result, many vintners are making record profits.

Yet amid all that good news, there is one gnawing problem that has faced, or will face, nearly every winery in California--the small root louse called phylloxera.

The bug has been around for most of the history of modern winemaking. Native to most of the United States, it destroyed European vineyards in the 19th century, probably traveling there on vine cuttings brought over from the New World. Phylloxera, just 1/25th of an inch long, kills by feeding on vine roots. It swarms by the millions on the root systems, and essentially starves the plant of vital nutrients. Native American varieties developed an immunity to the pest through natural selection, but European vines used for fine winemaking offered no defense. There is no effective treatment to battle phylloxera once it has found its way into a vineyard, and the only prognosis is vineyard death. Eventually, phylloxera was controlled by grafting European vine cuttings onto resistant American rootstocks, with whole vineyards being torn up and replanted.

Ironically, the California wine industry boomed for a while in the 19th century as European vineyards withered. Given its ecological isolation from the rest of North America--behind the wall of the Sierra Nevada and the expanses of the surrounding deserts--California, like Europe, had no native phylloxera (except, perhaps, for a small native population in, of all places, Death Valley).

However, phylloxera made its way to California as well, just a bit later, probably in the same way it reached Europe. Vineyards died, were torn up and later were replanted, though many wineries never recovered from the economic devastation of the massive crop failure.

In the postwar years, when the California wine industry was experiencing a resurgence, researchers at the University of California at Davis, the state's premier wine research institution, recommended a rootstock that they believed offered enough resistance to phylloxera while also producing a copious crop of grapes. It was called AxR No. 1, and the state's grape growers soon selected it as their preferred rootstock. The boom in California grape growing was built on massive plantings using AxR No. 1, which were conducted despite warnings from France that the rootstock was in fact susceptible to phylloxera infestation.

Those warnings seemed to be ill-founded until 1983, when phylloxera struck a vineyard planted on AxR No. 1 rootstock in the heart of Napa Valley. The vineyard was located just south of the town of St. Helena. At the time, I was working as a newspaper reporter for the "St. Helena Star," and wrote a story about the discovery. Though the effected area was small, the implications were profound. The vast majority of Napa Valley's vineyards were planted on AxR No. 1, and if the rootstock was no longer resistant, then they all faced eventual doom.

Yet there was little general alarm. The general response was that more research was needed to see if it was truly a new form of phylloxera, or just an aberration. But it was probably too late even then. Phylloxera can take up to five years to grow, and it spreads in a vineyard before vines start dying; later, one Napa vineyard consultant would liken phylloxera to AIDS. And like a terminal disease, there appeared to be similar stages of psychological recognition by the grape growers affected, from denial to rage to acceptance.

At every stage in the phylloxera saga, the worst-case scenario has always played out: What first became evident in 1983 has proceeded on a fairly predictable trajectory all the way to 1998. While UC Davis did not formally issue a proclamation warning against using AxR No. 1 until 1989, the handwriting had been on the wall for at least four years prior. AxR No. 1 was doomed. Despite that evidence, growers continued planting AxR No. 1, perhaps out of a misguided belief that what had worked so well in the past would continue to work well in the future. Amazingly, some Napa growers continued to use AxR No. 1 until 1992.

From that small St. Helena vineyard, the spread of phylloxera took on logarithmic proportions. In the five years from 1988 to 1993, phylloxera-affected vineyards in Napa County grew from a total of 100 acres to an estimated 10,000 acres; by the end of that period, the louse had jumped to neighboring Sonoma County. Replanting costs approached $20,000 an acre, and it was estimated that more than half of the 68,000 acres of vineyards then extant in Napa and Sonoma would eventually have to be replanted.

Today, phylloxera-induced replanting is drawing to a close in Napa County and is about half-done in Sonoma County, according to UC Davis viticulturist Andy Walker. However, phylloxera is still on the march in California. The next target for massive replanting is Mendocino County, which lies just to the north of Sonoma County. According to one estimate, 60 percent of its 17,000 acres of vineyards are still planted on rootstock susceptible to phylloxera. Even the highly touted organic grape-growing efforts of Fetzer Vineyards offer no protection from the depredations of phylloxera. Its appetite is insatiable. Organic efforts may have slowed its spread in Fetzer's AxR No. 1 vineyards, according to Walker, but the end result will be still be the same: death and then a costly replanting.

"The cold truth is that phylloxera is in Fetzer's vineyards and throughout Mendocino County. There's going to be a lot of accusations and name-calling on how it spread, but phylloxera is there and will destroy susceptible vineyards," Walker explained. "The final word on AxR is that the rootstock is not resistant to phylloxera."

Of course, as in many other disasters, there's a silver lining behind the cloud. The replanting induced by phylloxera has sped a revolution in California viticulture that many cite as key to explaining the increasing quality of the state's wines. Closer vine spacing, better pruning and advanced cultivation techniques have produced more flavorful and more concentrated grape crops in recent years. And California vintners have been lucky in being able to absorb the high cost of replanting in these fat days.

But phylloxera will always be out there in some form, ready to rear its ugly head. According to Walker, there are still many unknowns about how phylloxera lives, from its life cycle to its eating habits and how it was able to transform itself into an AxR No. 1 eating machine in California. There are also plenty of other places in the world that could be ravaged by phylloxera, but haven't been. Chile, for one, has most of its grapevines planted on susceptible European roots, but phylloxera has yet to attack.

Ominously, Walker has seen evidence of phylloxera in vines planted without resistant rootstock in the Australian state of Victoria. While there are quarantine measures in effect to halt its spread, Walker is skeptical that it can be contained in the long run. Grape growers in Australia seem to be in the same state of denial that their California brethren exhibited in the late 1980s, he said. The stakes could be just as high due to the fact that most Australian vineyards are planted on their own roots, according to Walker. If that seems far away, many of the vineyards in the California's Santa Barbara County are on susceptible rootstocks, and there have been reports of phylloxera there as well. The louse is also spreading throughout Oregon's vineyards. It appears that phylloxera will be around for quite some time to come.


This column, Unfiltered, Unfined, features the opinionated inside scoop on the latest and greatest in the world of wine, brought to you each Monday by a different Wine Spectator editor. This week we hear from assistant managing editor Kim Marcus. To read past Unfiltered, Unfined columns, go to the archives. And for an archive of senior editor James Laube's columns, visit Laube on Wine.

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