Thursday, May 31, 2012

Despicable Dollar Spot

Dollar Spot is the most common turfgrass disease around. Traditionally, the disease is easy to diagnose both by the lesions it inflicts on the grass blades, as well as the tell-tale mycelium that can be seen in the early morning. People often refer to this as having the appearance of a white cobweb. Interestingly, over the past few weeks, we have seen some Dollar Spot damage on the fairways, however it was not widespread, and there was no sign of mycelium. All indications were that a fungicide application in early May knocked down the disease, and we were just seeing the remnants of earlier activity. As the days passed though, we saw no recovery in these areas, and the patches of turf with Dollar Spot damage were slowly growing larger.

Dollar Spot disease on a fairway.
Since we weren't seeing any clear signs of active disease in the field, a plug was taken from a fairway and placed in a plastic bag outside for 24 hours. As you can see in the picture below, the greenhouse effect of our home made incubation chamber did the trick in forcing the pathogen to show itself.  There was no question that this was, indeed, quite active, and a fungicide application was made to take care of this problem. 

An abundant quantity of mycelium on this plug.

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