Click here to see the original posting (5/24/09).
In the case of the photos posted in the quiz, this was a case of several factors that resulted in the perfect storm. This research putting green has two different soil mixes. The healthy turf on the left was predominantly a native soil, while the discolored turf on the right had been excavated about 4 to 5 inches deep and filled in with sand several years ago. The end result was a fast wilting of the turf during a high and dry period. In this case, the turf starting to head south in a matter of a few hours. Exacerbating the problem and likely putting it over the edge was an excessive thatch layer and moderately aggressive vertical mowing. Some things that I found interesting and helped in the diagnosis were:
1. Notice the wilted turf surrounding the vertical mowing. The only area damaged, however, is the area where sand is the primary growing medium. Turf growing in the native soil (left) appears healthy. (The area on the far right was growing in sand, but not vertically mown)
2. Turf around the irrigation head was likely under less drought stress and therefore did not wilt.
3. Wicking. Bentgrass growing in the sand, but within about 3 inches of the native soil putting green was healthy. This was the result of the water "wicking" into the drier sand mix and therefore providing enough moisture to keep the turf from wilting.
The photos can be deceiving and most probably thought that this problem was caused by a misapplication of some herbicide or fungicide. The bottom line is that turf diseases "generally" don't appear in straight lines! This is a good example of how turfgrass managers must investigate well beyond the visual symptoms. I just can't wait for the TV show next season..."Turfgrass CSI".