I've had a small cinnamon tree in my apartment for 3 years and last week I noticed the leaves were begining to drop off. On closer inspection of the soil I found spider mites. I talked to the garden expert at Lowes and she recommended an insecticide soap. I've applied the soap but now there seems to be a kind of white fungus appearing in the soil around the roots. Do I have an additional problem?
The white fungus, may be fungi consuming the possible oil/fat based part of the product you applied. On closer inspection it may also be the oil/fat component that has risen to the top, fungi,bacteria... will move in and partially metabolize it. Try sprinkling some Store bought Cinnamon on it, which is generally made from a Cassia species, Cinnamon, is a Cinnamon species., if you are concerned. Both are quite strongly antibacterial, in general. Good luck.