What are the implications of this very warm winter on anthracnose for 2012?
I don’t think anyone really knows the impact of the winter on the population of the fungus. If there’s a lot of winter damage, is anthracnose coming in on weakened turf and causing a problem that way? I think we’ve seen more severe anthracnose coming in mid-to-late spring on top of areas that have been severely damaged by winter, maybe something like what we had last year. This year is probably one of the mildest winters we’ve had in many years. The only way I could see anthracnose being more severe is if it’s colonizing turf with these temperatures in the 50s and 60s. The caveat is that we really don’t know the impact of the mild winter on fungus.
What should superintendents do to prevent anthracnose from becoming a problem this spring?
The bottom line for superintendents is trying to follow the best management practices that we’ve developed over the past 4 5 years to try to maintain vigorous, healthy turf. That’s the best way to deal with anthracnose before you start considering fungicide strategies.
Whether warm or cold, try to improve your cultural program in the spring or summer. Anthracnose is a stress-related disease. With a mild year where the turf is not stressed as much, I would think it might play to the advantage of a superintendent. The turf is not damaged as much, so we go into the spring in a healthier condition.
You want to look where you’ve had a history of anthracnose before, and you want to maintain a healthy level of nitrogen, in particular. You might want to increase your spoonfeeding programs. Take a look at mowing heights. You don’t want to mow below what that species has been developed for: a tenth of an inch and below and continually mowing at that height would weaken the turf. Maintain an reasonable height of cut, with increased rolling and topdressing, which we’ve learned is a really important agronomic practice from the perspective of anthracnose in particular. Sand tends to reduce the severity of anthracnose throughout the season. A little more heavily in spring going to light or moderate in summer is a good approach to reduce the severity as well.
Avoid wilt stress, which tends to predispose plants to anthracnose. You can run your greens dry, but not to the point where you’re getting repeated wilt.
What we don’t know is the impact of winter temperatures on the survival of the anthracnose pathogen.
How should superintendents look for anthracnose, if it is showing up already?
Supers have to always be on the lookout for the yellowing associated with anthracnose. Look for the black porcupine spines of the fungus. Even if they see a small amount in the spring, always send it off to have a lab examine it.
From the standpoint of wet conditions, you need moisture for the disease to occur, but for the most part it’s much more prevalent where there’s desiccation.
When should a superintendent start to really look for turf disease this spring?
I think it basically goes back to control. For people who are using early spring applications for dollar spot, typically those go out on the second mowing in very early spring. This year, if turf starts growing a little earlier, that application might go out a week or two earlier than it has in the past. Keep an eye on the turf: when it’s actually picking up green tissue that’s about the time to do it. I can see how that might get pushed up a little because you’ll probably get growth a lot earlier this year unless we get another strange cold spell. It may only be a week or two sooner. I don’t know if there’s a big impact with this winter, but they should just keep their eyes open a little earlier than they normally would.