Conserve (active ingredient is spinosad). It isn't cheap though. http://www.dowagro.com/turf/products/insecticides/conserve.htm
Do you think the Malathion may take care of the problem?
My dad picked and burned, picked and burned. Then he paid us a penny each to pick and burn.
Remember that the earlier the treatment the more effective it will be. Here's a list of other control options. I think I'd try one with Bt, Bacillus thuringiensis:
Kathy, bagworm is listed on the Malathion label, but I don't think it is very effective. It is very difficult to actually kill a bag worm.
And so...we are back to burning them. Of course, at the time of our infestation, the impacted trees were within reach.
They killed 6 of our 10 foot cedars. By the time I figured out they were BAD for the trees it was too late. We burned the trees. Chopped them down. :(