Insects, diseases, and other pests all may add to the stresses affecting trees, decreasing their overall health or, perhaps, ultimately resulting in their death. Trees experiencing significant environmental stress, such as that resulting from construction activities, are often more susceptible to pests than are healthier trees. It is particularly important, therefore, to become aware of potential pests and to monitor trees for pests during and following construction and minimize their impacts.
One can perform this monitoring oneself, but because of the extensive specialized knowledge required, most individuals will retain the services of an arborist. Proper identification of the pest is critical in order to identify if control is necessary and, if so, the proper control strategy.
On occasion a pesticide may be required to ensure adequate control. Scales, for example, are sometimes found on stressed trees in numbers that require control with a pesticide to ensure the tree's survival. Preventive pesticide spraying, in which a pesticide is applied in anticipation of a pest, is less common today than in the past, but there are still situations, such as when dealing with borers, when it may be appropriate. For maximum effectiveness, environmental safety, and human and animal safety, be sure that pesticide application strictly follows label recommendations.