How to Identify and Treat Rust Plant Disease

Hi Judy!
I am having a problem with my plant. It’s been doing very well for the last three or four months since I brought it home. However it gets these rust-colored areas on the leaves.
It’s not in direct sun, but indirectly sunny spot. It’s close to a humidifier. I try not to overwater and I also try not to let it dry out. Any thoughts? Also, thoughts on how to get rid of fungus gnats would be greatly appreciated! Thank you so much! Melanie


Hi Melanie,

Rust Plant Disease: Your plant has a fungal disease called Rust Plant Disease. The good news is that this disease does not kill the plant, but it does ruin the appearance of the leaves. If Rust is present, the plant gets brownish, rust-colored spots on the back of the leaves and large pale spots on the top of the leaves. The best way to check if Rust is present, is to wipe the spots with a white cloth. If the cloth turns orange, Rust is causing the spotting.

Treating Rust: You need to remove the infected leaves to prevent it from spreading. Get rid of any leaf debris in the soil. Keep the leaves dry. Leave plenty of space between plants so there is good air circulation. Water early in the day, so the leaves and soil have started to dry by nightfall. You can apply copper sprays or sulphur powders to keep it from returning.

With fungus gnats,  allow the soil to thoroughly dry out. This eliminates the eggs and gnats in the pot. Use yellow sticky cards to trap the gnats that are flying around. If this doesn’t solve the problem, spray with the same fungicide you use to treat the rust.