Does rolling greens following a contact fungicide application affect results?

By Gary Deters

Over the last two seasons we have been researching if rolling greens post contact fungicide application affects the efficacy and effectiveness of the fungicide. The results of the trial could possibly take out the guesswork and allow golf course superintendents to make confident decisions. Rolling greens (Figure 1) is a cultural practice golf course superintendents use to help increase green speeds, remove dew, and promote smoothness of the putting surface. 

Figure shows a grass lawn with a lawn mower in the center. It has been shot on a sunny day and the shadow of the lawn mower is visible.
Figure 1. Greens roller. Photo - Gary Deters.

The turfgrass disease involved in the study is commonly called dollar spot (Clarireedia jacksonii) (Figure 2) and it is considered one of the most expensive diseases to treat on golf courses. With the help of Dr. Dominic Petrella, we have a great setup on our creeping bentgrass (Agrostis stolonifera) in order to perform research on greens with a history of severe dollar spot infections.

Figure shows pink flowers with grass in the background
Figure 2. Marked dollar spot infections on research green. Photo - Gary Deters.

The idea of the trial came when a couple golf course superintendents were asking if rolling after the application of a contact fungicide affected its effectiveness. Since this question has not been answered by previous research, superintendents or turfgrass managers would benefit from a replicated research study.

We have a collaboration with researchers at Ohio State University, who are also performing the rolling/fungicide study. Inclusion of fertilizer, systemic fungicides, plant growth regulators (PGRs) wetting agents, biostimulants, and other products would need to be an additional study because we need to make sure nothing else influences the results besides the fungicide application and rolling. By having the same trial in another part of the country it should give us great data and help potentially lead to more studies in the future. So far the research results indicate that rolling does not affect efficacy to any significant degree, but we have more work to do before making a definitive recommendation to superintendents. I am excited to potentially help the golf course industry answer an unknown question (Figure 3).

Figure shows a lawn with dark green and light green patches
Figure 3. Research green post application and rolling. Photo - Gary Deters