The cocoons are elongate, brownish to sand colored capsules averaging about 22 mm long. They are usually situated in an upright position just beneath the soil surface. The combined period of cocooning and pupation averages about 28 days. Occasionally larger roots are also attacked. Areas attacked often have masses of gum, mixed with frass, exuding from the bark.
Young trees are at times completely girdled and subsequently die.
Older trees are often so severely injured that their vitality is lowered and they are rendered especially susceptible to attack by other insects or by diseases. The PTB can be controlled by thorough, well-timed insecticide applications. An orchard spray directed against the adults will also control other pests present at the time. PTB pheromone trap catches can be used to time these sprays. Another treatment directed at the larvae calls for the application of a trunk spray anytime between July 20 to August 1.