Clarification on dollar spot in home lawns

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.  

In our last Landscape Alert issue, I wrote about some of the turfgrass diseases we’ve been observing on turfgrass sites (see Turf diseases getting pesky in turf).  With respect to dollar spot I wrote, “Dollar spot is also a disease that occurs on turfgrass that might be under fertilized.  This is especially true on home lawn situations and just like red thread a light fertilizer application will help the turf recover from the symptoms.”  Apparently some have construed these comments to mean that dollar spot is only a problem on under fertilized lawns.  That is certainly not the case, I was trying to make a point that in some situations we do see dollar spot on lawns that might be a little lean and a fertilizer application may help the turf out-grow or creep back over the damaged areas. 

Dollar spot could be argued as our most prevalent disease on turfgrass in Michigan.  Dollar spot occurs when temperatures are between 60°F and 90°F, which covers pretty much all of summer.  In Dr. Vargas’ book,
Management of Turfgrass Diseases, the cultural management practices he recommends for dollar spot infestations include keeping nitrogen fertilization levels and soil moisture adequate to facilitate turfgrass growth.  However, in some cases the cultural management practices will not be enough to suppress or mask the symptoms of dollar spot, and a fungicide program may be necessary.  Don’t make the simple assumption that the only reason you have dollar spot is because you haven’t fertilized, if it was that easy golf courses would not have nearly the challenges with managing dollar spot that they do.

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