More troubles, woolly aphids this time?!?!?!?

There are more troubles brewing in one of my cultivated tanks. What I thought initially was nothing more than some white fungus growth due to my use of BE-1 organic fertiliser (it was written on the packaging that "useful" white fungus growth would be expected) turned out to be some sort of pest attack again under scrutiny.    

Could these be woolly aphids? I was very tempted to use Provado Ultimate Bug Killer but I suspect that the cryptocorynes would not be able to take the pesticide. My mum recently used it on her plants which were hanging over my submersed cultivation tank and I suspected that that was the cause of a sudden cryptocoryne melt in that tank.

I guess I am left with no choice but to rely on the flooding + guppies technique again...