San Jose scales about a half-inch in diameter encrust twigs and branches. When they mature, legs emerge and the crusty shells begin to crawl. They feed on the foliage and fruit of apple, apricot, currant, gooseberry, peach, nectarine, pear, plum, and sweet cherry trees, causing small reddish spots. They can kill limbs or entire trees. To discourage scales, coat all of the parts of the tree thoroughly with dormant oil spray in early spring. Ladybugs and their larvae provide good control. If scales persist, spray with diazinon or malathion after the crawlers hatch.
