COURSE CARE
Early Winter Concerns: Disease Activity And Soft, Wet Playing Conditions January 8, 2014 By John H. Foy

Along with leaf spot disease, Pythium disease has been experienced on putting greens at a few golf facilities in Florida. While not normally a problem with bermudagrass putting greens, the weather has been perfect for Pythium and, as seen in the image, turf damage can be severe.

While most of the country has been dealing with winter storms and a recent blast of arctic air that resulted in record-setting cold temperatures, it has been an opposite situation in Florida. So far this winter, average daily temperatures have been running five to 10°F above normal for this time of year. This has made for a very enjoyable early winter golfing season. However, warm temperatures combined with the persistence of high relative humidity and dew points that are 20 percent above normal are also presenting additional course management challenges.

These environmental conditions are ideal for fungal disease activity, and Bipolaris leaf spot disease has been especially problematic for courses in the central to southern part of the region. The continued employment of a preventative fungicide treatment program on putting greens has been required to avoid severe outbreaks and, in turn, maintain a dense and healthy turf cover. It has been found that, in general, the use of contact fungicides and making applications on the shortest label recommended interval has been producing the most consistent and best results. Leaf spot disease is also being experienced on tees and through fairways and roughs. Fortunately, in most cases, large acreage fungicide treatments have not been required.

In mid-autumn there were reports of outbreaks of Rhizoctonia zeae leaf and sheath blight, which is one of the more difficult-to-control diseases of bermudagrass. When outbreaks and damage were experienced, increased nitrogen fertilization was undertaken to produce full recovery as quickly as possible before the onset of winter. While a necessary measure, there have been cases where this resulted in increased Pythium disease problems. There are many fungicides that include Pythium control on their labels, however, when disease pressure is very high, as has been the case for the past several weeks, the use of fungicides that are specifically labeled for Pythium control in a rotation with broad-spectrum fungicides is advised so that problems are not experienced when turf growth and recovery is at its slowest.

In addition to disease concerns, golfer complaints about soft and wet playing conditions have been common. Superintendents are being accused of overwatering, but the reality is that at most golf facilities little or no irrigation has been applied over the past six to eight weeks. The persistence of soft and wet conditions is a consequence of weather. High relative humidity and dew points combined with limited sunlight because of the persistence of moderate to heavy cloud cover greatly reduces evaporation such that the turf surface and soil cannot dry out. This situation is further compounded by occasional periods of moderate to heavy rainfall. Normally, the transition from the rainy season to the dry season in Florida occurs sometime during mid- to late fall, but so far this has not happened. Golfers need to understand and accept that until there is a change in the current weather pattern, there is little opportunity to produce drier and firmer playing conditions.

Source:John Foy (jfoy@usga.org)

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