Brown Patch by Charles Bohmfalk

It is that time of the year when we are now entering the fall season that brings cooler weather and humid, rainy conditions.  These conditions when the overnight temperatures are below 70° F and the daytime temperatures are in the 75° F to 85° F range can lead to many problems in the lawn.  Brown patch is one of the lawn diseases that becomes a real problem in our lawns during the cooler and more humid weather conditions in the fall and early winter months.  A number of popular lawn grasses are susceptible to brown patch: Berumda, Carpetgrass, Centipede, Fescue, Kentucky bluegrass, St. Augustine and Zoysia.  Other grasses may be infected as well.  Brown patch may be identified as circular or irregular shaped patches of light brown, thinned grass.  The grass may appear yellowish and have a smoke ring on the outer edge.  Leaf sheaths become rotted and a gentle pull on the leaf blade will easily separate the leaf from the runner.   Most fungicides will do an effective job if used as a preventive treatment.  Brown patch may be harder to control once the fungus is established.  The Texas A&M website (aggieturf.tamu.edu/answers4you/disease/brownpatch.html) lists some of the more effective fungicides.  There are other fungal infections that may resemble brown patch.  The same fungicide may control that problem as well.

I recently had a brown area in my lawn.  Brown areas caused by grub worms will show a browning or the appearance of a lack of water in the area.  The damage may be a small spot or cover a large area and is caused by white grub worms, the larvae of the May or June bugs.  The larvae feed one to two inches below the surface and destroy part or most of the root system of the lawn.  Damage usually appears in late July through early August.  If the damage is heavy, the sod can be easily lifted up or rolled up.  To verify that the problem is grub worm damage, dig one square foot sections to a depth of 4 inches.  Treatment with an insecticide is necessary if more than four grubs are found per square foot.  Since my lawn damage was in an area where I have had a problem with grub worms before, I treated the area with an insecticide.  The grass is already showing good signs of recovery.  If left unattended in the fall, the grub worm will survive over winter and become very active in the early spring.  By this time, the grubs have done more significant damage to the grass roots and large areas of the lawn may not survive the winter.

Cinch bug damage appears as irregular patches in sunny areas, usually along driveways, sidewalks and house foundations.  The grass first turns yellow and eventually dies and turns brown.  To identify a chinch bug infestation, remove both ends of a metal can and twist it into the grass.  Fill the can with water and a little detergent.  In a few minutes, the chinch bugs will float to the surface.  They are black with white wings folded over the body.  Treat with an insecticide that has cinch bugs listed on the label.  Read the label and carefully follow the directions when using any fungicide or insecticide.