Yeah I agree with the others, its time to repot.
You should be able to get the extract at a health food store. Although you could also check the spice ilse at you're local food shops.
I've dealt with these lil buggers a few times being in my phrags. Something that would work well for me was a soak then repot then finally a tablespoon of mouthwash with some water - (beer cup size) then added right down into the fresh media. Not the minty stuff just the regular golden listerine.
Good luck