My rubber tree is indoors by a window and watered about once a month. It has new growth but has begun to have spots of yellow on leaves and some have a small hole on them. There are no bugs as far as I can tell. The plant is about 7 feet and is 5 years old. I have never had this problem before and it has been in the same place for years. I have a smaller rubber tree in another room that does not have this yellow stuff. Please advise.
Indoor Rubber Tree Has Yellow on Leaves
Certified GKH Gardening Expert
It is likely a fungus. There are several that can create those yellow spots. Treat the plant with a fungicide. I like neem oil myself as it treats both fungus and pests and is safe for people and pests. This article has more information on it: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm