Difficult to see with that picture, but I know the name of it in French, you can have a look :
https://www.google.de/search?q...
Thanks for the link
It is write to treat it with Insecticidal spray: soap, horticultural oil, neem.
I use black soap + natural oil + alcohol.
I never eard about "neem", if I understand correctly, this is a tree oil wich make the plant disgusting for insects ?
Interresting !