We have 200+ blue spruce on the west side of our property. Bagworms love them. Last summer we drenched the trees with Thuricide. We sprayed around the 1st of July. Now, it seems they have mulitplied! Never seen so many bags! Was last summer a late summer for bagworms? Should we have sprayed earlier or later. Is there something else to use that won't hurt the birds? Too many questions, I know. We need to thin the trees as they are crowding each other. But, the bagworms have us worried.