Sometimes it’s difficult to tell whether dead or dry patches on your lawn are caused from lack of water, the neighbor’s dog, or from lawn fungus. With all the hot, rainy weather we had this summer, lots of folks called us saying that there grass was “browning out” or dying. “Brown patch” is a fungal disease of hot, humid weather. It is most common when night temperatures and relative humidity stay high for several days and are accompanied by rain. Disease development can be very rapid under such conditions. Expanding patches of discolored grass up to several feet in diameter mark the presence of a severe outbreak.
There are two things you can do that will limit brown patch in lawns: (1) Avoid nitrogen fertilizer applications just before or during hot weather. (2) Water deeply and late in the day. When a lawn has had previous brown patch problems, fungicides may be applied when humid weather and hot nights are predicted. Applications should continue according to the fungicide label for as long as the hot, humid weather persists.