Leaf Spot Disease is characterized by brown, moist spots on the foliage. In a serious attack the spots can enlarge and merge, killing the whole leaf.
The Leaf Spot disease is caused by various bacteria and fungi.
Many houseplants can be infected by Leaf Spot Diseases but Citrus, Dracaena and Dieffenbachia are highly susceptible to this disease.
1.Remove and burn the affected parts to reduce the risk of spread to the rest of the houseplants.
2.Spray the affected plant with a systemic fungicide and ensure all the parts are completely covered with the fungicidal solution.
3.Keep the plant on the dry side and do not mist it for several weeks or employ other techniques to raise humidity for your plant. Read more on how to raise humidity for houseplants.