https://www.campmor.com/c/72-in-tight-weave-no-see-um-mosquito-netting-61001?...Check that out.
Tight weave flexible screen
Might be able to use a mosquito net head protector. Check the Wal-Mart camping section.
I Guess polyester would be able to take the environment.
Heck, a patch of a piece of 100% polyester cloth, painted , squegeed in, with the glue, like you'd do fiberglass..
Might hafta glue it up, then cut to size.
Probably cut the perimeter out except for one or two Tails to hold it down by, smear it good, trim and apply.