The following tips apply to all regions where Tall Fescue is grown.
Brown patch, caused by the Rhizoctonia species fungus, is the most common disease that can develop in a Fescue lawn. It appears as a brown or yellow circular patch of grass that can vary in size from a few inches to several feet in diameter. Tall Fescue grass is more susceptible to brown patch during the hot, humid summer months. Lawn fungicide or fungus control can be applied to the lawn after brown patch has appeared, but it is best to take preventative action and begin applying fungus control for the duration of the summer months.
We recommend beginning lawn fungicide applications when nighttime low temperatures rise to 60°F. Typically, preventative applications are made at 14 to 30 day intervals, depending upon the fungicide. There are an abundance of lawn fungicides available that prevent brown patch and other lawn diseases. Many of our stores carry these fungicides.
Following good lawn care habits can also help prevent diseases. Here are 4 tips:
Avoid over watering by only irrigating when there has not been sufficient rainfall. An established fescue lawn needs 1 inch of water per week (maybe more in the height of summer).
Also, keep Tall Fescue grass mowed to a minimum height of 2.5 inches, never cutting more than 1/3 of the blade height at each cutting.
In addition, do not fertilize tall fescue grass during the warm months; fertilize only when this type of lawn, classified as a "cool-season grass," is actively growing during the cool months of early spring and late fall.
Topdressing in the autumn with organic compost is a sound organic fertilization practice that also provides good types of bacteria to the lawn that may out compete disease-causing pathogens.