2024 - What I did today

Sounds like mites - they are too small for me to see: I know they are there by the damage they cause and when it is really bad, the webbing, leaf on the right. The one on the left is just starting to show damage.

You might be right. The leaves look very similar to mine, although there's no sign of webbing. Next trip to the greenhouse I'll take powerful lens to see if they are visible. Next question, what do you do about them?