In over 20 years, I had never encountered bagworm in the Boston area. This pest is more common to the Mid-Atlantic and coastal regions as far north as Cape Cod. However, I found it in several locations this summer – including in a public parking lot in Watertown, as seen in these photos. These are mature arborvitae, some of which were completely defoliated. It is too late to treat at this stage, so speak to your arborist now and make a plan to manage this pest next spring.