Mystery disease

Though we have diagnosed thousands of turf disease samples over the years, we were confronted this week by symptoms that we have never seen before, nor are they described in any of the turf pathology texts.

The host is Poa annua on greens in the San Diego area. In our first look at the problem, we saw these green rings showing up following fungicide applications that were made to control brown ring patch (Waitea circinata).

An application of Heritage (azoxystrobin)…