Talk about taking one for the team. If you're an eco-friendly earth muffin who refuses to use anything chemical-ridden on yourself and the environment around you, then there exists a gnarly - though effective - approach to killing a tent worm infestation that you may want to try out if you're not squirmy.
Rather than spraying insecticide onto a tree, which works but also depletes populations of good bugs in the process and may make you grow a third arm from all the contaminants, you can simply pick an unlucky tent worm and squish it with your finger.
According to this video, squishing one will freak the other tent worms out and they'll quickly bounce.
Tent worms usually leave after a couple of weeks. They'll either turn into moths, or just leave your tree. But, before they leave, they do cause a lot of damage to your tree. An easy option to killing tent worms is insecticide. But, insecticide can also be a problem because it can kill bugs that need to be on your tree to pollinate. And, it can also be harmful to humans. So, if you are a bark licker or a bark eater, or anything like that, this might be a problem for you. Now, if you don't want to use insecticide, I have an option. But I must warn you, it's a little gross. You see, if you see a tent worm, you just go up to it, and you just squish it. And then all of the other tent worms around it will get freaked out and just leave. It's only temporary, but it will get rid of them for a while.