A scale insect, known as San Jose scale, is a common pest of roses, apples, plums, nectarines, apricots, alder, almond, arborvitae, ash, beech, birch, blackberry, ceanothus, cherry, chestnut, elm, fig, eucalyptus, grape, hibiscus, orange, peach, persimmon, raspberry, walnut, willow, and the list goe...