An historical investigation into the bug that wiped out the vineyards first of France and then of Europe in the 1860s. A young French botanist, Jules-Emile Planchon, discovered that the tiny aphid Phylloxera vastatrix had accidentally been imported from America. He believed that only the introduction of American vines, which appeared to have developed a resistance to the aphid, could save the French vineyards. Many disagreed but eventually Planchon won the day and phylloxera-resistant American vines were grafted onto European root stock.