Phylloxera was a vine louse that nearly destroyed all the vineyards around the world. France decided to take American vines and make French wines. They did not know the American vines that formed a resistance to the louse were carrying phylloxera. The old world vineyards were vulnerable and the louse who feeds on the roots of the vine destroyed a third of the worlds vines beginning in 1865. It was the greatest threat to wine production in history. Thomas Volney Munson, The Gr