Rainfall has definitely returned after a dry July in Lemont. So the moisture component of the environment needed for fungal development has returned and with some cloudy nights the temperatures have been favorable too. Lately, dollar spot has taken off and so has brown patch here on Sunshine Course. After such a slow start for turf diseases this summer, I decided to look up the levels of dollar spot in our untreated plots at North Shore CC (north suburb) and Coyote Run GC (south suburb). In 2008 we had a slow start for dollar spot development, but we saw a large difference in our two locations. Now this year we had a cold spring combined with a cold and dry July. This year our two locations are more similar, but it is interesting to see that dollar spot at Coyote run is taking a similar spike as last year but the development is still a month behind (see graph below).
Our data at North Shore CC seems to be bouncing up and down this year as it did late last year. Why would we see that? Well Derek reminded me of all the differences between each site. Besides turfgrass differences of L93/Southshore vs. bentgrass/Poa annua blends and weather differences, there are differences in management. Dave Ward at Coyote Run has kept our plots on a practice facility dry. After dollar spot comes in less water keeps the bentgrass from recovering. There are many differences of each location, and that is just the reason for testing multiple years and locations. For now the research continues.
In other disease news, the rain has relieved moisture stress and rust is no longer an issue in our tall fescue trial. Rust is interesting that it tends to become visible during dry conditions but that is when the plants are stressed and rust pathogens do their best work. I made an attempt at rating the disease across all the varieties and was surprised to see some differences (see graph below). Some plots had many leaves affected which flagged bright yellow while other varieties were all green. Out of 58 varieties 2 showed the most symptoms with 10 percent of the leaves affected.
Derek Settle, PhD
Director of Turfgrass Program
Chicago District Golf Association
11855 Archer AveLemont, IL 60439