Bagworms are easy to pick out, a nuisance to pick off and tricky to kill with pesticides. They tend to like the cedar family (think arborvitaes and junipers).
What is a bagworm?
Bagworms are bugs that craft houses out of silk and tree debris. They live and mature while feeding on the leaves of their host plant. The female remains caterpillar-like while the male matures to look like an insect. They can do severe damage when left to take over a plant. If caught early enough, it is possible to limit any long-term damage.
If you suspect that you have an infestation here are some tips to keep them from becoming a problem.
1. First, identify that you are indeed dealing with bagworms and not just dead needles, etc. They will look like this picture above. When you pull on them, they will give some resistance. Pull the branches apart to get a better look. You will find them scattered throughout.
2. Pick them off by hand. Because they are encased in a “bag”, it is difficult to spray the bugs/larvae directly. There is a window of time for pesticide application when the larva is more active outside of the bag. Timing will vary by climate (zone).
3. Bag them up. Don’t make the mistake of picking the bags off and dropping them back onto the ground. They will climb their way back into the tree to continue their feeding frenzy. If you hand pick the bags, put them into a trash bag and dispose of them to ensure that they are unable to regroup.
Knowing what you are dealing with is half the battle. If you think your plant issues are the cause of insects, take time to identify them before seeking any chemical solution.