Rings of dead grass are typical symptoms of patch disease.
We’ve been encountering a fair amount of “patch disease” on lawns in our customer areas in the past week or so.
The term “patch disease” refers to any of a number of fungal diseases that attack the roots of turfgrass. They have the characteristic symptoms of crescent-shaped or circular patches of dead grass surrounding clumps of green grass (the resulting appearance called “frogeye”). However, streaks of dead grass or incomplete rings can also be seen, especially when the disease has advanced.
When you first spot signs of patch disease, call in your arborist. Though the damage is done, s/he will apply a fungicide to stop the blight from spreading further. To restore a healthy turf, the best option is to core aerate and overseed the lawn — over the next three to four weeks — with better, disease-resistant grasses. Then keep the patch disease from returning by getting on a preventative fungicide program in the spring.
