In the last ten years, Anthracnose has become a serious problem we expect to see in summer during warm to hot weather. Normally it responds to curative fungicide applications under these conditions but increasingly fungicides appear to be having little or no impact. Possibly, but there are many other explanations including poor timing of applications, misdiagnosis of symptoms, and failure to coordinate cultural practices with disease control efforts thus stressing turf at a time when infection is likely. As bad as the apparent summer Anthracnose problem is, a bigger problem seems to be cool weather or winter Anthracnose. This disease occurs as scattered yellowing of individual tillers which slowly die and cause turf to thin out over a period of weeks or months.
Fungicidal control is often ineffective once symptoms are observed.
Anthracnose may be due to incorrect diagnosis, or more likely to poor timing of applications. Since we are dealing with the crown rot phase in winter it may be that sprays will have to be timed earlier or be applied as drenches to better target infection sites. Currently our efforts to understand these problems are hampered by the lack of any active turf pathology research in the Northwest region. Other diseases are generally easily controlled using standard fungicide application strategies. As long as turf managers accept the reality that annual bluegrass is susceptible to many common diseases and plan accordingly disease control on Poa annua putting greens is no more difficult than on bentgrass.