Tree injection is used when control or prevention of a severely damaging pest is crucial for survival. Tree injections should only be performed by a trained and qualified Plant Health Care Professional.  When injection methods are used to apply pesticides or nutrients, small holes are drilled into the “cambium layer” of the tree. The pesticides or nutrients are then injected into the vascular system of the tree and quickly translocated throughout the canopy. Because drilling into the tree creates wounds, it is not recommended to use tree injection when less invasive methods are practical. The “emerald ash borer” & “bacterial leaf scorch” are two of the most common pests requiring tree injection methods to achieve effective control.