Grapeleaf rust mite

Grapeleaf rust mite is 0.2 mm long, cream to pink in colour, wormlike and possesses two pairs of legs near the head. Rust mites are in the same family (Eriophyidae) as bud and blister mites but are much more active. Rust mites over-winter under the bark of cordons or the trunk near the crown.
Smaller numbers can be found under the outer scales of dormant buds. Lower nodes of canes tend to have the most heavily infested buds. At mid to late chardonnay woolly bud (when less than 10% of buds are at the first green tip stage), the mites start to migrate to the swelling buds and produce the first generation. Two weeks after bud burst most of the mites have migrated to the developing shoots and leaves.
There is increasing awareness of the damage that rust mites can cause. Early season rust mite damage can be confused with bud mite or cold injury, as the leaf distortion or crinkling symptoms and poor shoot growth can be similar. The damage is most obvious from bud burst to when five to eight leaves have emerged.