Are Bagworms Dangerous, and How Can I Get Rid of Them?
It’s magical to watch a butterfly emerge from its cocoon. You marvel at the kaleidoscope of fluttering hues before you as it expands its wings!
That feeling of awe, however, is lost as a black, fuzzy moth emerges from its sack! Before making their appearance, the moths, most likely bagworms, were busily munching your evergreen or tree.
Jodie H., a Davey Blog reader, saw them on her tree and inquired, “My mimosa tree has bagworms.” “How am I going to get rid of them?”
Learn about bagworms, the harm they do to trees, and how to manage them in the sections below.
Bagworm Infestation and Control
How do bagworms appear?
You’re more likely to observe the 2″ dwellings bagworms build in your trees than the bagworms themselves. In the autumn, the insects combine their silk and tree parts to make a cocoon-like bag, which they fill with up to 1,000 eggs!
When the eggs hatch in late spring or early summer, tiny black larvae emerge. They’re slightly bigger than a pinhead at 2 mm, making them as light as a feather. The caterpillars travel to nearby trees using their silk thread as a parachute and begin building a new home (or bag) there.
The pests remain in their sacks until the adult males emerge to breed in late summer or early autumn. Male bagworms are ashy-black moths with translucent wings that are about the size of a quarter.
Bagworms originate from where?
They are native to North America. However, they are mostly found in the Eastern United States, with populations spread over the East Coast and much of the Southeast.
Bagworms do what kind of damage?
Bagworms will attack around 120 distinct tree species. They do, however, favor evergreens such as juniper, arborvitae, cedar, and spruce.
Bagworms begin chewing after they’ve picked a tree to call home.
They devour a lot of the buds and leaves on evergreens, causing the branch tips to become brown and die. However, if they consume more than 80% of the tree, the whole evergreen may perish.
Bagworms nibble tiny holes in the leaves of deciduous trees (those that lose their leaves in the winter) and may cause defoliation. If the bagworms are removed, these trees will generally recover.
Bagworms also wrap silk around the twigs on which they construct their bags, which might kill the tree twigs in a few years.
What is the best way to get rid of bagworms on arborvitae, evergreens, and other trees?
You won’t enjoy it, but the simplest approach to get rid of bagworms is to cut off the bags by hand and destroy them. Make sure to remove all of their silk as well, since this might choke (and kill) twigs later.
If that’s too unpleasant for you, or if there are too many bagworms to remove, we can assist! When the larvae are active in late spring or early summer, a qualified arborist may apply a treatment to the tree until they are no longer visible and feeding. This varies by region, so check with your local arborist to find out what is best for your area.