is this 'red blotch' or leaf burn?
put my bulbs on the balcony 2 weeks ago. were healthy. been raining a lot, especially last week, they got drenched, but are mostly in bark and perlite, so drain well.
some days were very hot and sunny. just noticed on the underside of one leaf red blotches, feels rough to the touch. not insects. top of the leaf looks ok. other leaves on the same bulb ok, except some have small red spots on the underside only. I think 1 week ago they were all fine.
the affected leaf is the newest one, it was turned underside to the sun. could it be 'sun burn' or might it be virus?
other bulbs next to it have no problems.