Necrotic Ring Spot
Good Day, I have a HOA which has been treating for NRS for a few years. The treatments have not solved the issue and we keep spending money on them. Is there a treatment which works or are there other ways to rid or control NRS?
Adams County Colorado
NRS is a difficult issue to treat. There is a very narrow range of chemicals which are effective and they need to be applied in the spring. Even with the best treatment all that is normally achieved is suppression of the fungus. Fixing the underlying cultural issues which are creating conditions favorable to the fungus is the long term solution.
Conditions which favor the disease include; over watering in the spring, over fertilization in the spring (especially with quick release fertilizers) and mowing the turf short (2.5 inches to 3.5 inches is a good height). You might also consider starting to over seed with a NRS resistant variety of bluegrass or perennial rye grass (which is immune to the fungi). Our factsheet on NRS goes into more detail: http://www.ext.colostate.edu/pubs/garden/02900.html
The first step you might consider taking is confirming that you do in fact have NRS. Many things can be misdiagnosed as NRS. If you would like to send in some pictures or bring in a sample we would be happy to look at it. We also do site visits for which there is a small charge if you would like us to come out and look at it. Hope this helps please let me know if you have any further questions.