RUST, LEAF SPOT, AND DOLLAR SPOT
I am currently teaching the advanced turf course, Hort 451, on the web. A part of that course, each student completes a paper or project. Mary Broadfoot, a senior in Animal Ecology, chose to do 9 extension type bulletins. Three of these are on turf diseases, three are on insects, and three are on weeds.
These tuned out so well that I have decided to share them on the blog site. I will include them three at a time over the next few days. The first three are on diseases. She chose Rust, Leaf Spot, and Dollar Spot.
They are attached as pdf files below. You can get the full text by clicking on the individual words below. Several of the pictures used are from the internet. She has sited each location from which information was used.
LEAF SPOT SHOWING UP ON CREEPING BENTGRASS FAIRWAYS
Conditions have been very wet in the Midwest this spring, which has resulted in a very fast growth rate of turf. Most of us are having a hard time keeping up with mowing. These wet conditions in spring are often followed by a leaf spot breakout in turf. The picture below is from the Chicago area. It shows the typical leaf spot symptoms on fairway bent.
Symptoms generally include blighting from the tip down on bent, rather than the standard leaf spot lesions seen on other species. The turf on the area may also look like it is dry, even if the soil is wet. The grass also takes on a brown "haze" when you look at it from a distance.
The fungi that causes this is usually attributed to Bipolaris or Dreschslera (formerly Helminthosporium), depending on the author. I will let the pathologist sort that one out.
Chlorthalonil (Daconil and other commercial names) is the standard answer for this problem, although there are several fungicides labeled for this disease.
This disease can also hit greens, but most golf courses are treating greens and it is not as common as it once was. Because of the cost, fewer superintendents are treating fairways and that is where we are seeing most of the problem this spring.