The insect is called Gall Wasp and can spread from tree to tree. We have spoken with a variety of Arborists and The Cape Cod Cooperative Extension Service and have found varying opinions. One thing they all agree on is that there is no guaranteed cure or remedy. There are however, steps that can be taken to assist in the survival of the trees. Trees that are stressed are more likely to be susceptible to the infestation. Maintaining tree health and vigor and avoiding stressors such as drought, defoliation and other infestations help to reduce die back. There are also a couple of options to treat the wasps that are being tested and also have no guarantee.
If trees are significantly infested, the best solution is to remove the tree to reduce the chances of additional trees being affected. Also something to take into account is the locations of the infected trees. Any that are near structures and may be comprised could potentially be a hazard in the upcoming winter.