Yes, I do have a scope, the $10 one from radio shack. I can't find any bugs at all. Or egg masses. I even shook the leaves over paper to knock anything loose. Nothing.
Running a 600w air cooled. I have misted the leaves before (R/O), but I don't think it's that since lower leaves are affected as much, or more than upper leaves.
MG organic potting soil with composted manure, perlite, and granulated lime is the medium. Go box nutes, heavy schedule. R/O water mostly. Used rain water the last couple of times. Adding GO box "cal-mag" as well. Jamaican Dream, about a month old.
That scope should be enough to see bugs, right?
Also, they were in/out from seed up until about a week ago, right next to the tomatoes.
Outside during the day, in the tent at night to finish the on cycle. Been at 19/5 for about 10 days. (that works better for me than 18/6 schedule-wise)
I know that's risky for all sorts of reasons but I deemed that risk acceptable, and I'm not yet convinced that's what started it.
Thanks for the help, fellow growers. What can I do to help you with a better diagnosis?
Unfortunately, I can't take a leaf to the neighborhood nursery.