Sue,
@sooby first THANK YOU for the great article on the rust research!
I'd like to note that after I waded through the whole, one thing did stand out and that is the rust doesn't occur once the ambient temperatures get above a certain level. It likes to grow in more moderate temperatures. So at this hot time of year, you may not see any proliferation of rust anyway. The heat may take care of it for you. I had some rust on my few non-resistant clumps in April but as soon as the heat turned on in May, it disappeared (after I cleaned out all the rusty leaves) and hasn't returned.
If I were going to use the Ultra Dawn treatment (and I'm for sure going to try it!) I will wait until the temperatures start to be more moderate - here it will be late August before it's dependably below 90ish in the daytime, and down into low 70's at night. Using detergent on your plants at this time of year is risky - if you do, be sure to spray in the evening, and rinse the plants off in the morning before the sun hits them.
