How to rid Leland Cypress of Bagworm
Yes, that is quite an infestation of bagworms. Most of these look like old bagworms from last season. Have you seen any evidence of them hatching out yet? Right now you would see small, dark caterpillars moving around feeding on the trees. The bags don't develop until later in the summer. Most likely, the damaged areas will not regenerate. So it is up to you whether you want to treat them and give them more time or not.
As soon as you see bagworm feeding you need to treat as the caterpillars have to ingest the insecticide. It will not work preventively. When it is time, and it should happen shortly, spray the trees with Bt.
Please refer to the information on our website for more details,