Leaf spot or melting out of Kentucky bluegrass is caused by a fungus. It manifests itself by football shaped blots in a purple or reddish hue with the center more tan colored. The leaf spot fungus can come on at a rapid pace. Not knowing what it is, most people will start watering the spots by hand or turn on their irrigation systems to water more frequently. This is exactly the wrong thing to do. Check the other areas of your lawn to see if they are getting enough water. It they are and the irrigation system has good coverage, then you need to turn back the watering times or frequency to help combat this melting out action of the fungus.
The beautiful fairy ring appears in rings, or semi-circles that are initially one foot or less in diameter. If they are not taken care of over the years, they will expand every year. Typically these rings are spotted with they are in the three to six foot diameter size.
Fairy rings are other type of fungus. Not only will the ring appear in a darker green color, but there will be small mushrooms within the darker green grass that will be a dead give away for identification of “Fairy Ring”. Also the grass affected by the fungus will grow at a faster rate than the surrounding turf.
The annoying Dollar spot will appear as small spots. It will show up as the size of one dollar coins and the color of tan. Many times the dollar spots will grow in size if they are not treated. If this disease is not treated it will kill of the areas affected.
These three common diseases are easily treated. Thru a variety of simple measures, the areas will respond quickly to your care of the affected lawn areas. Mechanical means of treating the diseases are cutting your lawn at the proper height with sharp blades. The best mowing height for Kentucky bluegrass is 3″ to 4″. This will allow the grass to shade the soil beneath it for better use of rain and irrigation water. Also, by keeping the lawn cut high it allows enough of the stem for the grass to photosynthesis and produce all the goodies it needs to keep itself healthy.
Our first recommendation, but listed here second, for lawns that we see is to cut back your lawn irrigation considerably and let the areas affected dry out. Fungus loves the wet, spongy overwatered parts of your lawn.
Property dethatching your lawn every year is a must-do. Thatch build up can can multiple problems with you lawn. We have a great post about that right here!
One other item to think about: Make sure you are properly fertilizing your lawn. A balanced yard with the proper nutrients are key to keeping all those pesky problems from you lawn and making it easier for you to enjoy it while not always working on it.