only with a picture(s) can you get help. Bagworms are seldom found in pine and locust.
Might be a climate difference...bagworms are quite common on honey locust and not uncommon on white pine up here (northern Ohio). They are most common on arborvitae and they hit blue spruce pretty hard - sometimes eastern redcedar too. Quite a bit on crabapple. I have found them on Norway spruce...but the I have seen other infestations where they are heavy on a blue spruce and there are NONE on the adjacent Norway... There is a wide list of trees they get.
Not too much of a problem when they do get into honey locust and crabapple because it is usually such a late season defoliation so the tree comes back fine next year. However on evergreens, they can defoliate and kill entire (medium-sized) trees.
If reasonable pick them off and put the bags in soapy water. Of course most people don't notice them when the population is small enough to do this. It is getting a little late for effective chemical control - but I don't think the door is shut quite yet. If you spray too late, the will just stay in their bags and decide they are done eating.
Ohio State lists: acephate (Orthene), bendiocarb (Ficam, Turcam)(*), bifenthrin (Talstar), carbaryl (Sevin), chlorpyrifos (Dursban), cyfluthrin (Tempo)(*), diazinon, dimethoate (Cygon), fluvalinate (Mavrik)(*), malathion, nicotine sulfate, pyrethrum, permethrin (Pounce)(*), rotenone and trichlorfon (Dylox, Proxol)(*) in
this fact sheet.
I sub-contracted to have some trees sprayed August 15 and Talstar gave a good kill. If you can get them earlier in the season
Bt is the preferable treatment to me because it is not a broad spectrum.