Redberry mite—Acalitus essigi
Redberry mites are extremely small and elongate. They are whitish and invisible to the naked eye.
The redberry mite is primarily a pest of blackberry. Ripening blackberries with redberry mite infestations
do not darken in color. They become brighter red, hardened, and sour and remain on old canes through
winter. All or only part of the berry may be affected.
Tolerate or prune out and destroy infested fruit. Both
mature and immature mites remain inactive during the winter,
hiding under bud scales, and migrate to flowers in the spring
to attack developing fruit. A delayed-dormant
application of sulfur after budbreak
in addition to an application at bloom or when shoots are
2 to 6 inches long may provide control. This treatment also
helps control powdery mildew. Several applications of horticultural
oil spaced 2 to 3 weeks apart after green fruit stage
may also provide control. Don't apply oil within one month
of a sulfur application. Try to plant least susceptible varieties;
'Himalaya' and 'Evergreen varieties' are the most susceptible
to redberry mites.
of blackberries on left