Bag worms

Anyone ever dealt with bagworms in their evergreens? We have a row of 60+ foot high cedars that act as a screen and windbreak. This year, the bagworms are overtaking them, no matter how much we spray (you can only get so high on that tall a tree). A couple look like they're dying, others have big brown areas. We've hand-picked thousands of them off. They're even getting in the landscaping shrubs.

I hate losing these nice old trees. Ideas?