By Cole Stover, Oregon State University
It’s fall in Oregon and that means microdochium patch season has begun. With cooler temps and wetter mornings we’ve begun to see signs of disease and are excited to share our progress with you.
Microdochium patch is typically seen during fall, winter, and spring in the Willamette Valley (Figure 1). This spring we began a trial looking at whether the annual rate of nitrogen and potassium on annual bluegrass fairways has an effect on disease pressure. We applied various rates of nitrogen (1-4 lbs/1000 ft2) and potassium (0 – 4 lbs/ 1000 ft2) to our Poa annua fairway. At the same time we began a study to look at whether or not the timing of the last application nitrogen and potassium (Sept, Oct, or Nov) plays a role in disease pressure. Plots will receive no fungicide treatments through spring. We will take photos of the study area that will be analyzed to see what percentage of each plot is infected (Figure 2).
We expect to see higher amounts of Microdochium patch in the plots receiving high amounts of N and K. We also expect to see higher amounts of M. patch in the treatments that receive applications later in the year. We hope that the results of this study will inform superintendents about how their annual fertility plan can affect Microdochium patch pressure.