I am trying now with "Plantella" Incecticid & Acaricid.
First indications are hopefull but it is too early to say anything conclusive.
I don't care about stains on the leaves because deformed leaves mean that I have to grow the plants for some time before they look OK again in any case. Also, my goal is not so much to have plants for show(ing), but to maintain varieties and species in the long term. That they look ugly for some weeks or months is to me not so relevant.