How to Manage Pests
Pests in Gardens and Landscapes
and life cycle—Erineum mites
Erineum mites overwinter under outer bud scales and move to unfolding leaves in spring. They associate
in small groups to feed on lower leaf surfaces; the result is production of masses of enlarged leaf hairs
inside a blisterlike area on the leaf (the erineum). On the undersides of the leaves, beneath the swellings,
are concave, densely lined, felty masses of oversized leaf hairs in which the mite populations develop.
As the population increases, some move to new areas or to other leaves and form new erinea. From mid-August
to leaf drop, there is a movement from the erinea back to the overwintering site underneath the bud scales.
surface of leaf
of grape leaf