Borers

Most woody landscape plants can be attacked by borers.  There are many types of borers, the Emerald Ash borer being the most known.  The larvae bore beneath the bark into the wood on tree limbs, trunks, and main roots.  Damage can vary from foliage being discolored, wilt, limbs may die back, and branches or entire plants may die.  Borers attack mostly damaged or dying plants.  Healthy trees are rarely attacked.  Pesticide applications to the bark have not been found effective.  Injections of insecticide can provide control depending on the damage that is already done.  The best prevention is to keep trees healthy.