Phylloxera: (Fill-ox-er-a)
by Brenda Francis

When the early European settlers arrived in North America, they found the native grapes, vitis labrusca. It didn't take them long to figure out that labrusca made ordinary, musky tasting wines. They tried to grow the beloved grapes of Europe, vitis vinifera, but were unsuccessful. Vinifera varieties, such as cabernet sauvignon, chardonnay, and pinot noir, would not survive more than a few seasons in this new world. They believed the cold winters prevented the vines from flourishing. These early settlers did not know there was another foe working against them.
     The mystery of why vinifera grapes would not grow in the United States would not begin to unfold until 1862. A French wine merchant introduced the native American labrusca grape varieties to the Rhône Valley of France. The rootstocks contained a stowaway, the yet undiscovered phylloxera aphid.
     This tiny root louse feeds on the roots of the grapevine. Phylloxera does not affect the flavor of the wine, but the grape yields dramatically diminish each year, eventually killing off the grapevine within a decade. The native grape varieties of North America, Concord, Catabwa, Niagara, Michigan, Delaware to name a few, have thicker, phylloxera resistant rootstocks.
     Once this aphid was introduced to the vineyards in the Rhone Valley it took less than a decade before the entire wine industry of France was brought to its knees by the blight. Devastated, vineyard owners tried everything from introducing a natural predator to using chemicals on the soil. Many who did not own land or who did not have the financial resources to fight the blight fled to Spain and the new world regions of Chile, California, Argentina, New Zealand, South Africa, and Australia in the hopes that the plague would not follow. Unfortunately the parasite found its way to all these grape growing regions within a decade or two.
*     In 1870, American Botanist Charles Riley suspected that grafting vinifera vines onto American rootstock would offer a solution to the blight. Riley began sending phylloxera resistant rootstocks to a botanist in the South of France, Jules-Emile Planchon. Planchon was successful growing grafted vinifera varieties in phylloxera infested soil. The first few vintages of Planchon's new American hybrid was said to be undrinkable. The French rejected Planchon's work. After a few more seasons, the grafted vines began producing wines of fine quality. By 1914 all of France was replanted with the grafted grapevines. Almost all infested areas were replanted with resistant rootstock within the next few decades world wide.
     This wasn't the last time the wine industry battled with phylloxera. As research about phylloxera progressed, many different resistant rootstocks were bred. In the 1980s a new strain of the phylloxera aphid evolved. The type of grafted rootstock used in Europe has been unaffected by the new strain of phylloxera as of this writing. The rootstock chosen in California proved to be only moderately resistant to the new strain of phylloxera.
     Just as California's wine industry was coming into its own, the first signs of die-off were showing up in its cherished Napa Valley. The expensive task of tearing up the grapevines would begin again. The cost of the latest phylloxera blight to the California wine industry is an estimated $750 million. Ironically, the replanting of vines continues one-hundred and forty-five years later, in the very soil where the native grape and root louse thrive in harmony.