Today I got a sample in from a golf course superintendent in New York. The sample was thinning and several of the plants had a bleached appearance almost like you would see following the application of Tenacity (they didn't put any of this out BTW). Upon further inspection, there were no signs of any pathogen (no Pythium, bacteria, or any other fungi...I don't check for nematodes so not sure about this). One thing that was interesting was the elongation (not etiolation) of the stembases and stolons. The symptomatic plants had roots being initiated a good inch or so down from where the plants were tillering. These symptoms made me immediately think of the elongation that has been shown to occur with repeated applications of Proxy (Dernoeden's article), but I wouldn't say that this is a cause/effect in this case.
According to the superintendent, the symptoms are definitely occurring on some of the newer introduced varieties (greens were rebuilt in 1993 I believe). Based on the images, it looks like there are weaker clones that have segregated out and more impacted by whatever is going on. I have seen these symptoms on older/weaker clones following aggressive cultural practices, but am not aware of anything like this on new cultivars. I really don't have an answer, but thought that it was an interesting case that was worth posting if for no other reason than to get comments from any other pathologist or golf course superintendents that have experienced this.
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