Hi Ron,
I can't really tell by your photos if there is rust on the foliage or not, when I enlarge then they get a little blurry.
The foliage on daylilies that have rust will eventually yellow and die
http://www.daylilies.org/ahs_d...
It also looks like it could be summer dormancy which will tend to happen toward the end of the season (doesn't neccessarily happen in the summer, just when it's really hot). Sometimes the roots will be rotting off and this will cause it to look like this. I have heard it referred to as summer rot (again doesn't have to be in the summer). It's not the same as crown rot, but the plants will shrink and the foilage will look like yours.
Since they have been in the bed for about 5 years they may have sunken too deep and just need to be lifted up so the crowns isn't more than an inch below the soil. This can cause the plants to start rotting also, being too deep.
