Bag worm prevention

Asked May 8, 2018, 8:54 AM EDT

Hello - we had bag worms last year pretty bad on our evergreen arborvitae trees. They were black worms in sacs that hung from the trees - two of the trees died. We are trying to catch them in the Spring with some preventative care. I read that there was a way to stop them before they start - if we can take care of it in the Spring. What can I do to prevent them? Last year we sprayed them with a nasty chemical to kill them. There are still some dead sacs hanging from the tree. Do I need to remove them? Thanks!!

Anne Arundel County Maryland

2 Responses

Yes, if you can reach the bags, by all means pick them off. They could each have hundreds of eggs. Don't merely drop the bags on the ground where they can still hatch eggs. Drop in buckets of soapy water and let them 'drown" or dispose of in the trash.

Even if you get all the bags, you may want to spray this spring, just in case some are still in the area. The good news is that the recommended bt is a very safe product for humans and animal-life, too. Click here for info on what to do and when:


Thanks so much for the info!