mites, minute insects which feed on leaf surface cells and which can be an important grapevine pest worldwide. Those that feed on the leaves include grape (or grapeleaf) rust mite (Calepitrimerus vitis); Pacific spider mite (Tetranychus pacificus), which is the most destructive; two-spotted spider mite, which is only occasionally found on grapes; and Willamette mite (Eotetranychus willametti). Mite feeding slows photosynthesis and can reduce grape ripening.
In Europe, red mite (Panonychus ulmi) and two types of yellow mite (Eotetranychus carpini and Tetranychus urticae) cause the most damage. They feed on green parts of the vine and can affect fruit set and cane ripening, as well as reducing leaf health.