Spraying to kill Pine Bark Beetles. Systemic tree injections to kill heavy Borer infestation.
What causes Pine Bark Beetle infestation?

Pine Bark Beetles attack trees stressed by drought, disease, fire, flooding, changes in the water table, improper irrigation, excavation and filling due to construction, and malnutrition. All pines are subject to attack by one or more species of bark beetles. All stressed trees give off resinous chemicals [terpines] which attract bark beetles. Sometimes sheer numbers of beetles may overwhelm a tree despite its apparent vigor.

Tree Care and Aboriculture