Hi all, of one of my Dracs recently some spots occur. In fact however, they were faind only ot the top of the leaf and I didn't pay much attention but they quickly go down and covered the whole leaf. The conditions are right for Dracs, the temps are right, the air movement is right, the water is right, the potting mix is aerated enough, the light and so on. I don't use fertilizers for all my Dracs and they flower happily, even this plant at the moment, so should I be worried and can someone tell me what is it and what to do? Thank you.