Biological control of the two-spotted spider mite, Tetranychus urticae, Koch, on strawberry was obtained with mass releases of the predaceous mite Phytoseiulus persimilis Athias-Henriot, during preliminary studies in the coastal area of southern California in 1964.

Victor Voth assisted with the establishment and cultural maintenance of the strawberry plot; James McMurtry supplied the Phytoseiulus persimilis; and Glenn Scriven reared the predaceous mites in the insectary at the University of California, Riverside.