The “bags” of a bagworm are constructed by spinning the foliage of the tree with their silk. These bags can often be mistaken with a cone on a conifer.
What are Bagworms.
They usually feed on the foliage of many conifers but occasionally can be found on deciduous trees. The bagworm damages its host tree by eating away large quantities of foliage that can cause the branch to die back. This leads to patches of dead branches. In extreme cases of repetitive defoliation a tree can be stressed to the point of dying.
Treatment of Bagworms
Bagworms are difficult to keep controlled due to the fact they go undetected until late in the summer when it is usually too late to treat effectively. For the best control, treatment needs to be done in early to mid summer. In the fall and winter the bags can be picked off and raked up around the base of the tree to help keep the population low for re-infestation the following year.
Trees that Bagworms feed on.
Bagworms do not have a specific tree they target, although they do prefer conifers. The following is a list of trees that are commonly susceptible.