Bagworms can be destructive to a variety of plants, including: arborvitaes, red ceders, junipers, oaks, sycamores, maples, and apple trees, just to name a few. They camouflage themselves by creating a cocoon (or bag) out of debris from the plant they are attacking/feeding off of. The females never leave the larvae stage and will continue to feed off of the host plant throughout the year.

Life Cycle
Eggs (300-1000) overwinter in the bag. In early summer the eggs hatch and larvae crawl out from the safety of the cocoon and drop down by spinning threads of silk which often are caught by the wind, distributing the larvae to new locations and host. This is why local populations can boom while other areas seem unaffected by this pest. Once on a new host, the bagworm will begin to create a new cocoon from it’s own waste (about 1/8” long). There the larvae will continue to feed and collect portions of debris from the host plant, continuously working to enlarge it’s bag to fit it’s growing body size. In late summer, bagworms attach their cocoon to a new sturdy branch with a strong silken thread (like spider silk which can cause girdling of the branch if not removed) and prepare to pupate. The males emerge as large winged insects which resemble fuzzy black bees and the females remain as larvae still attached to the branch of the host plant. After they mate (late summer/Early fall) the female dies within her cocoon and the cycle starts all over again.

Trees and shrubs Attacked: Bagworms attacks a wide variety of trees: Spruce, Firs, Pines, Hemlocks, Arbervities, Junipers, Beeches, Locust, Elms, Honeysuckles, Chestnuts, Maples, Poplar, Sweetgums and others.
Damage to look for : Defoliation, typically from the top of the tree downward Browning of needles (conifers) Holes in leaves