The insect phylloxera eats the roots of a grapevine. North American vines are not affected by the insect. Because of this, most grape vines around the world are grown on North American root stock. Phylloxera once almost wiped out the entire European wine industry.
Acidity
Acidity in wine is the level of acid that the wine contains. Wines with more acid in them taste more tart or sour.