Small, greenish yellow insect ( Phylloxera vitifoliae , order Homoptera) that is highly destructive to grape plants in Europe and the western U.S. It sucks fluid from grapevines, causing galls to form on leaves and nodules on roots; eventually the plants rot.
It was introduced into Europe from the eastern U.S. in the mid-19th century and within 25 years had almost destroyed the grape and wine industries in France, Italy, and Germany. Vines were saved by grafting European plants to rootstocks of resistant vines native to the U.S. Hybrids and fumigants are used to combat the pest.