Phylloxera: The Louse That Killed California Wine Twice

The vine rows stretching out on either side of this road look permanent. They are not. They nearly weren't here at all.

Grape phylloxera is an aphid-like insect, barely visible to the naked eye, that feeds on the roots of grapevines. It is native to eastern North America, which means American wild vines evolved alongside it and developed resistance. European vines never did. In the eighteen sixties, phylloxera traveled to France on American rootstock specimens, and over the following two decades it destroyed somewhere between two thirds and nine tenths of French vineyards. The solution, grafting European varietals onto resistant American rootstock, was identified by the eighteen seventies.

California vintners knew the solution. It did not save them.

Phylloxera arrived in Napa Valley in the late eighteen seventies. By the mid-eighteen nineties, it had devastated most of the valley's vineyards. The cost of replanting on resistant rootstock was enormous, and it came exactly as the industry was beginning to become profitable. Then Prohibition arrived in January nineteen twenty, and finished what the louse had started. The trained winemakers left. The market relationships dissolved. The physical infrastructure remained, but the industry was essentially dead.

That would have been enough. But the California wine industry has a habit of finding new ways to be destroyed.

In the late nineteen eighties, a second phylloxera epidemic began in Napa Valley. The cause was a rootstock variety called AXR-one, which the University of California had certified as resistant. It was not. Vineyards that had been replanted after Prohibition were wiped out again. Thousands of acres. A century of recovery, undone by a mistake in a laboratory that vintners had trusted with their futures.

The valley rebuilt, twice. The vine rows in front of you are the second generation, or in some cases the third. What looks like permanence is agricultural stubbornness, grafted at the root.