Much a Do About Nothing

Twas the week before Field Day and not a disease was stirring. Relative humidity levels have plummeted in the Midwest and consequently so has disease activity. The main news throughout the Midwest is the Upper Midwest is extremely dry. Just today the Department of Natural Resources in Wisconsin has enacted a burn ban in Northwest Wisconsin. Fortunately the rest of the Midwest is not as dry. Dr. Derek Settle in Chicago only reported some minor problems with foliar anthracnose on annual bluegrass and reported a dollar spot lull.

Foliar anthracnose is fairly common throughout the Midwest. One superintendent in Madison equates it to a glorified skin rash. The picture that accompanies this post shows the extent of symptoms were are seeing in the Midwest. When symptoms are not severe, it appears that increasing nitrogen, even slight really helps. Dr. Lane Tredway and Dr. Bruce Clarke reported in a recent Golf Course Management article that a tank mixture of Signature and Daconil was quite effective against anthracnose.

If you recall from a few posts ago, I mentioned our efforts with Dr. Damon Smith to develop a dollar spot forecasting model. To date the model has only kicked off twice this year. Partly because the model requires a 5-day average of 70% relative humidity. We have sprayed a series of plots immediately adjacent to our main dollar spot fungicide trial based on the model. Non-treated controls in the main fungicide trial have averaged 65 to 100 spots (largely in part to a week and half of weather in June), yet the forecasting plots remain perfectly clean. I recently spoke with a local golf course superintendent in Madison and he indicated that if he had followed the model he would have saved at least two fungicide applications this year!

These results are promising, but still very preliminary. We still need to see what happens later in the season. Interestingly enough the dollar spot fungus seems to induce symptoms under slightly different environmental conditions during the fall. At least this seems to be the case in Oklahoma. Only time will tell if this is true for the Midwest. Please stay tuned.