Why are my eggplants' leaves turning rusty and powdery?
Why My Eggplants Leaves Are Turning Rusty and Powdery
It sounds like you may have a couple fungal infections going on. One called powdery mildew and another called rust. I spray all of my roses and plants with a fungicide called Green Cure. It is available on-line here: http://www.greencure.net . It has worked great for me in getting rid of the fungus problems.