Yep, that looks like Dollar Spot, and it appears to be coalescing together in one area. As you are mowing, you are spreading the mycelium to other parts of your yard. You also need to make sure you wash off your mower after each use. Go get some Immunox from Lowes or Home Depot and apply according to label directions. I would suggest mowing the afternoon or evening before you apply, then apply Immunox early the next morning. Then do not water or mow for 24 hours. A repeat application will probably be needed 14 days after the first application. As I have stated on other threads, whenever I see Dollar Spot, I immediately think of a lack of Nitrogen, especially this time of year. Another way to tell if it is Dollar Spot is to go out to those areas early in the morning and see if they have a cottony, web-like appearance.

How tall is the parent plant? I you hold up the canes, they are about 4.5 feet tall. The habit is spreading. Does it repeat bloom? I didn't notice it bloom in summer and fall. It was nowhere near this big when we moved in last June. Do the bases of the blooms have a white-ish cast to them? Yes. How wide are the blooms, when they open, in inches? 2 inches. It also has a nice "tea" scent, not citrus, not overpowering. Thanks for your response, Ann !!!

Thank you all for your responses, especially to Jim for helping out. I also sent a picture to our local Agricultural extension office. They forwarded it to the plant pathology department at Kansas State University and this was the response from the plant pathologist "My first thought is physiological since all of the spots are clustered along the margins. Diseases tend to be more scattered. Another vague thought would be a Cercospora leaf spot. I tend to see it on roses in wet years. It is pretty minor. It has a light colored center with a reddish purple border. The symptoms here look similar but I still don't think the pattern fits because it is usually more scattered. At this late in the season I wouldn't recommend any control measures and next year it likely won't be a problem if it is drier and warmer". The county extension agent said "Most likely non disease. I think it looks like a scorch symptom from a spray. Often the oil carriers in pest control products can cause a burn like this if used above label rate or when temperatures are too high". Once again thanks to all. This is a great forum!

Its not environmental stress; like I said, all of my plants look that way, even the ones that have been transplanted. I haven't planted any more seedlings into the garden because I want to get rid of whatever fungus/ insect damage this is. It does look a little like the four lined plant bug damage, but the spots are irregularly shaped. I got some all-purpose insecticide/ fungicide anyway.