Tent worms

I went out to check on the plants the other day i saw some tent worms in a tree on the trail i take to get to my plants, we havent had tent worms in this part of michigan for about 5 or 6 years but there back. i was wondering if these are a threat to my plants?




http://www.apartmenttherapy.com/uimages/chicago/082708-ambermain.jpg

thats a link of a picture. thats exactly what they look like.

So far as I know tent worms and their kin (we have a form of them down here too) are mostly tree lovers and generally prefer trees to smaller plants.
I can't speak specifically towards their affection (or lack there of) for marijuana, but I wouldn't think it would be high on their target list. For one thing a colony that size on a pot plant would almost certainly kill it in short order, leaving the little buggers without food