Question From: Tucson, Arizona, United States
Q: I have a brown film under my geranium leaves that come off when i rub under the leaf its like a powder
A: I believe your geranium has rust. If it is advanced, it's best to destroy the plant. Otherwise, take samples of the leaves ( in a sealed zip-lock bag) to your local independent garden center for an accurate Id and recommendation of a fungicide. Be sure to treat the undersides of the leaves. Best And Happy Yardening, Nancy