what is this disease like, can you describe it ??

It looks like orange spots of pollen on the leaves,but will eventually kill the leaves. It starts on the bottom leaves & continues up .
Arlene

Arlene , i am bumping you up , got the same problem , cant be helped this year anymore , but i sure would like to know how to prevent it in the next season.
Anette

This sounds like what is happening to my Wyoming cannas. Is this really rust? What can I do to keep it from spreading to my other cannas? Is it possible to spread to my organic vegetable garden?? Please tell me if there is a treatment. My deceased Nana dug these beautiful cannas up the week before she died and gave them to me. I just can't thrown them out!
Distraught canna lover in TX

Don't know how effective these two treatments are, but I've heard anecdotal advice about pouring diluted milk on the plant to kill fungal disease, just the milk & water from rinsing out the milk jugs, poured over the affected plants. Secondly, spreading corn meal on/around the plant.

Last year I had rust terribly on many plants from the wet spring, and when I heard about the corn meal, I sprinkled it on the plants. The rust did clear up some, but, the weather was also drying up by then, so it wasn't a very conclusive which worked. I learned about the milk later, so didn't try it last spring.

I sprinkled the corn meal liberally on my aspen trees this spring, and they are almost fungus free, but we've had a dry spring.

Of course, in this hot weather, with the milk and corn meal, you might just be baking corn bread! (Oh, and your dogs will enjoy snacking on any clumps of corn meal you leave.)

Thanks so much, Kent. Your answer needs to go in the FAQ! I spent Friday evening trimming off infected leaves and squashing leaf rollers, and by the end of it I was almost ready to chuck all the cannas, but they're too gorgeous for that.

I also sprayed with a fungicide and of course it started to rain soon afterwards, but not too hard and not for very long... so I'm hoping maybe it had some effect. I'll get out there and re-spray when it dries up a little (probably September, at the rate we're going.)

The gardening expert in the newspaper printed the picture of my canna leaf with all the orange spots on it in the article where he said the only cure is to cut off any diseased leaves. I followed his advice and now my cannas are strong and flowering with no spots. Today I saw a leaf with several spots on my Canna En Avant and carefully removed it. I keep 11 different cannas, each in a large pot and watch them carefully daily. Some people tell me that dwarf cannas can develop orange spot from over-watering. I notice that my two giant red cannas can never get enough water and never get rust spots.

Because I cannot bear discarding a canna, I am willing to try anything to save my plants from rust spots. Rather than paint the infected leaf with cupric oxide and turn it blue, I tried a radical approach: I took a bottle of Isopropyl 91 alcohol and a cotton swab and painted over the rust spots for two days. The spots do not go away but they are stunted and do not further infect the leaf which is not harmed by the alchol. Now that I see this working I am no longer cutting off infected leaves. I have six potted cans on stands and I only notice the rust spots on my En Avant, Miss Oklahoma, and Wyoming cannas. I think thick leaf cannas like Tropicana are less likely to be infected than thinner, green leaves.