A wide variety of insects attack grapevines. Injury may occur as a result of direct feeding action, where reductions in leaf amount or leaf health can delay ripening with serious implications for wine quality, or by carrying (vectoring) a particular virus disease or phytoplasma disease.
Alternatively the vine root system can be attacked, which leads to development of water stress and restricted vine nutrition. While minor stress may enhance wine quality (see vine physiology), the more likely outcome of root damage by insects such as phylloxera (the most destructive of all insect pests) is severe stress or vine death. Some insect pests, such as phylloxera, attack only grapevines, while many attack a range of different plants.