Thanks for your response, Lars. I just removed them for not to think every day what it can be. Now I have another problem - small spots on the leaves tips. They grow biggger with time but never cover the whole leaf. Usually they appear at the end of July. First I thought it was because of the Danish cold summers with everyday rains, high humidity and lack of the sun. But this year they appeared again, on all my pleiones. Does anyone have an idea of what it can be? I have tried several fungicides but with no result at all.