Invasive insects and diseases destructive to your valuable trees and shrubs are opportunists that relentlessly attack any susceptible plant, whether it is under stress or not. The difference with stressed trees and shrubs is the likelihood of a recovery is much less, and with plants in landscapes there is always elevated stress levels.
These invaders attack all facets of the tree from roots, bark, branches, and leaves. Some are apparent, such as the Japanese beetle. Others are not so apparent, such as a wood borer, whose only indication is a small hole on the trunk. Even more evasive are the bagworms that attack Leyland Cypresses. These insects actually mimic a small pine cone that is normally associated with a conifer.
Unfortunately, this is the ability of insects to take what is yours. However, with the proper diagnosis and timely treatments, most pests can be brought under control and kept there. Every tree and shrub in your landscape has a pest that favors it most, and we encourage you to call roots to shoots for a free assessment for all of your trees and shrubs.