We’re having some problems getting our high school football field to withstand traffic as well as we would like. I’m going to send you a series of pictures. Hopefully pictures will be good enough to indicate the problem. Is it Poa trivialis that’s causing the problem?
Doug Watt, West Marshall, IA
When Doug called and submitted this photo it sure looked like this was an open and shut case of bentgrass contamination since the picture seemed to fit the problem. Creeping bentgrass is very intolerant of traffic and will become “puffy” with tufts of grass plants growing on elongated shoots when mowed at 2 inches. Tenacity herbicide would have been our recommendation to control bentgrass in Kentucky bluegrass.
But Doug was insistent that he already had a bentgrass contamination problem on his baseball infield and that the problem grass on the football field was something different. His first picture just didn’t have the resolution to zoom in on what we really needed to see.
When identifying plants or pests try to take and send a focused picture that is at least two megabytes so we can zoom in on roots, crowns, ligules, leaf blights, seeds, etc. Doug took some really great pictures that are posted on a November 16 blog at www.iaturf.blogspot.com/ .
We were also able to rule out Poa trivialis when he brought us some live samples. The field is a mixture of Kentucky bluegrass and perennial ryegrass that has been infiltrated with some patches of K-31 type tall fescue. Over the years it has been seeded with a mixture of Kentucky bluegrass and perennial ryegrass, including some of the newer Grey Leaf Spot (GLS) and tetraploid perennial ryegrasses.
We are fairly confident that there is a ryegrass component in the grass that is creating the aerial shoots and poor wear tolerance. Usually we think of perennial ryegrass as a very traffic tolerant grass system. We’ll follow up in the future when we get this completely figured out. Some of the other possible explanations that we are exploring are insect mites, some type of hybrid between tall fescue and ryegrass, or atypical growth from spreading ryegrass.
Our intent is to simply determine if others have observed this type of growth and if you consider it to be a positive or negative type of turf performance. At Doug’s field it’s some type of ryegrass with inferior traffic tolerance and that makes it a very unusual problem. Let me know if you have seen this at your facility.