you answered your own question.. it is a rust ...

as far as i am concerned.. its cosmetic.. and ignored ...

ken

See Rust Fungus on Wikipedia. Read the second paragraph.

i am really stretching the old gray cells here ....

but i seem to recall .... that it is a secondary issue ...

there has to be an injury to the leaf surface.. for the rust to attack ....

stuff falling out of trees.. cells burst in heat.. slug bites .... something has to 'open' the leaf.. for the rust to set in ...

but maybe i damaged that brain cell ...

ken

Earlier in the season, I moved Victory to a new, very very sunny location. It was clearly a shock to its system as the middle of the largest leaf (about 1/4 of its surface area) blanched to the parchment color associated with sun burn.

Now, that sun burn is completely covered with rust. I did not know, until reading that article, that I need to remove that leaf. Good to know.

Thanks everyone for the info. I bought these 2 hostas from a local place that digs the hostas for you. Their nursery is behind their home and they have a lot of hostas. These were growing in full sun. I noticed a few red spots but they were tiny and I really gave it no thought. I brought them home and put them in large pots and we've had terrible heat, humidity, and tons of rain since. I think this is why they have gotten so bad. I'm sure the weather hasn't helped them. I don't want it spreading to my other hostas, but I did notice some new leaves that look fine. Like I said this is a new one on me. I suppose if I keep them I must treat them some way or it will be back next year. Do you think I should just pitch them? Thanks, Nancy

When you clean up in the fall, be sure that you remove all the dead leaves of this plant from your hosta bed. Next spring, you can treat this plant with a fungicide early (before any symptoms appear), and it should be good to go. The symptoms could be related to being relocated and the weather conditions. The publication below could help you to identify specifically what ails your plant.

Here is a link that might be useful: Diseases of Hosta Iowa State U

manyhosta that was a great website, I put it in my favorites. Thanks!

I been having this same red spot problem on verigatedhostlverigated this year. I've moved the plants in order to alleviate the problem. It seems to have helped somewhat, but I have cut them back to almost nothing. I'm hoping the root system will take off as I've had a few new leaves. Like to hear any comments on the problems solutions.

The link to information from ISU that I posted in 2010 (above) still works and provides illustrations and advice regarding a variety of hosta diseases.