How to Manage Pests

Pests in Gardens and Landscapes

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.

Redberry mite enlarged
Redberry mite enlarged

Reddening of blackberries on left
Reddening of blackberries on left

Statewide IPM Program, Agriculture and Natural Resources, University of California
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