Historically, anthracnose is a problem on golf courses during middle and late summer when cool-season turf is most vulnerable to stress. This year, it already is a problem in some areas where mild conditions prevailed throughout the winter.
Once turf becomes infected with the anthracnose pathogen, it usually is a problem for the rest of the season. It is prevalent so early this year in areas that either had it last summer or have a history of it and where winter temperatures were so mild that it never really left, according to Ohio State University plant pathologist Joe Rimelspach, Ph.D.
"To clarify, this is on greens on Poa annua. Most likely, it infected those plants last year, because of the mild conditions in continued right on through the winter months," Rimelspach said.
"This is a nasty disease and one you want to get under control now before the heat of summer. You don't want crowns weak and infected going into the the summer."
The average daily high temperature in Columbus in January was nearly 45 degrees, which is 6 degrees above the historic average, according to the National Weather Service. In February, it was 54, which is 12 degrees above normal.
"If you have it, or have a history of it, make sure you are doing proper scouting," said Todd Hicks, program manager in OSU's turf pathology department in a video published on the Ohio Turfgrass Foundation Turf Tips page. "Once you have it, it's going to be with you for the rest of the season."
So long as it's going to stay wet you're going to have leaf spot. It doesn't matter if it's warm or cold. It likes both."
Ohio State's turf pathology department has published an anthracnose management guide that offers preventive tips, curative strategies and the role of cultural practices in avoiding the disease entirely or at least minimizing the risk.
A total of 12 inches of precipitation was recorded in central Ohio through the first quarter of 2017, and about 99.999 percent of that has come in the way of rain during what was an abnormally warm winter.
The wet ground has made it difficult for superintendents in many areas to find windows where it has been dry enough to pull plugs, spray or even mow.
"What this has caused is a lot of spraying nightmares," Hicks said. "People have had a hard time getting out trying to make their applications, trying to mow, trying to do aerations on golf courses and get those cores up without it being a sloppy, muddy mess."
Those conditions have joined forced to give way to a few other problems as well, including leaf spot.
"If this has been a problem for you, you need to get it under control now because it's only going to get worse," Hicks said.
"So long as it's going to stay wet you're going to have leaf spot. It doesn't matter if it's warm or cold. It likes both."
Rimelspach and Hicks have observed dollar spot only on a couple of occasions, but said it will be a full-blown problem soon. Fortunately, they added, there are several new products on the market that offer good control.
Check out their family of fungicides chart for more information on control options and how to avoid resistance issues.