San Jose Scale (Quadraspidiotus perniciosus) is a tiny insect that spends most of its lifetime attached to a limb, fruit or leaf where it sucks plant sap. The male is the only stage that flies, while the nymphs and females remain on the tree. Although most life stages have low mobility, populations on a tree can reach high numbers within one to two growing seasons. A single female and her offspring can produce several thousand scales in one season. If left uncontrolled, scale can make fruit unmarketable and even kill the tree.