Morning Glory Rust – yellow powder on back of leaves

Q: This yellow stuff is on the backside of my morningglory leaves. When you rub it it seems to be like a yellow pollen.

A: It is morningglory rust. Rust disease attacks many ornamental plants. One way to manage it is to immediately pick and destroy infected leaves. Try to keep leaves as dry as possible.

The fungicides  propiconazole (Banner Maxx) (click for sources) and azoxystrobin (Heritage 50WDG) (click for sources) can be applied if you have a high-value plant.

Rust – Flowers and Vines

Rust diseases of ornamentals