San Jose Scale is a somewhat overlooked pest that can result in reduced orchard productivity and tree death.
Scale literally sucks the juice out of the host plant, including apples and stone fruit.
Although generally controlled by spring oil applications, it may become more prevalent during periods of mild winter weather and where pesticide programs become softer. Look for slow, otherwise unexplained, dye-back of shoots and limbs as a sign of scale infestation. Red stippling of fruit at harvest is also a good sign of scale infestation. Adapted from Healthy Fruit , June 20, 2000.