If the fruit becomes infested it will be misshapen and often will drop to the ground. Insecticide sprays applied immediately after bloom may reduce plum curculio damage. Removal of wild plum in the area and practicing sanitation around the apple trees will reduce the problem. The adult scale insect is about 0.1 inch in diameter. It has a grey cover that hides the insects.
Scale insects have thread-like mouthparts that are inserted into the bark.
They feed on the sap. There are four generations a year in South Carolina. A single female scale can produce about 400 young over a six-week period. The young are called crawlers and move to a new area. They then settle down, insert their mouthparts, begin to feed and secrete the covering over their body.