I hesitated to respond because I have not had rust, but I know that James' directions for cutting back daylilies to near the crown is also shown (with pictures) on Sue Bergeron's rust site, and have been described elsewhere as tried-and-true standards for how to approach it.
http://web.ncf.ca/ah748/newpla...
However, I have often wondered about more resistant cultivars if, after trimming away just parts of the leaves that show rust, any remaining leaf areas might respond to a spray of mild liquid dishwashing soap and water, as the plant recovers.
There was a study done at the University of Guelph in Ontario, Canada (supported in part by the AHS) in 2004 that is also linked to Sue Bergeron's site. I don't know if further research there or elsewhere has found new or contradictory information but they reported that "Among the contact fungicides applied three days after inoculation, the dishwashing liquid was able to reduce rust development to a level not significantly different from that of the systemic fungicides". Perhaps
@sooby would be able to update, comment further, or explain if that would not have any helpful application after rust has already appeared (and whether it is a worse course to experiment than cutting back fully).
http://www.uoguelph.ca/~thsian...
But, since I use a mild soap and water spray to combat aphids, and find that it also improves the look and vibrancy of the leaves here, that is what led me to wonder if daylily plants that are only mildly impacted with rust (resistant to the rust) could still do well with some foliage intact.
Maybe if you have extra fans of a more resistant cultivar that is showing less rust, and at least two areas where they are located, so that you would not lose all of your cultivar by trying it out ... I wonder if it would be worth spraying mild soap and water on one set of the fans to see if they might do okay and still look pretty good in the garden, without having to cut them all the way back (or spraying and alternately rinsing, to keep the soap layer from building up and impeding respiration of the leaves)?
