The last 3yrs or so, around July 4, I get this problem(s). This year the edges got a burnt appearance. In the past we had a flea-eaten appearance, which your associates felt was flea mite. I’ve been diligent with malathion prewinter and thoughout the spring and summer. I’ve checked for slugs using a board. These hostas have been in place for 30yrs and just recently became problematic. Any thoughts?