What are Those Things Hanging in my Trees and Shrubs?

Updated: Aug 19, 2019

Giuseppe Baldi, GM Baldi Gardens, Inc


Our certified experts are here to answer the What, Where, Why and How of those pesky Bagworms you keep hearing about. Read more to find out how to spot them and what to do to get rid of them before they ruin your landscape!



What?

Those are bagworms! These caterpillars don’t typically present a problem every year and you may notice small numbers of them in any given year, but some years they emerge in droves and can completely cover and defoliate trees. It looks like this is going to be one of those years!


Where?

Bagworms typically make their “bags” in conifers (junipers, cedars, cypress, arborvitae, pines, spruces, etc.) and some broadleaf shrubs. The females construct these bags to protect themselves, their eggs, pupae and larvae. There are many different species of bagworms each species has slightly different life cycles and growth habits. Most bagworms pupate in late summer and after about 3 weeks the adult moths will emerge from their bags. This typically coincides with mating season, after which the femaless will deposit their eggs and die.


Why?

The bags these caterpillars construct are woven from silk and are reinforced with layers of leaves, twigs and bits of bark. There is typically a small opening at the bottom of the bag where the worm can expel refuse and waste. There is also a larger opening near the top of the bag where the worm can exit to feed or make repairs to their bags as needed. This upper opening is closed by the worm before each molting period a