Nematode Nick's Landscaping

A Beautiful Yard Naturally

Brown Patches

(Rhizoctonia solani)

 

Brown patch symptoms can be different depending of turf grass species, weather and severity of infection.  Brown patch is most susceptible in our area in the St. Augustine species.  The blades first will be purplish and appear to be water logged, then will dry out and turn straw colored.  The affected turf will normally be circular and after a time healthy turf start to grow in the center of the circle looking like a doughnut.  These circles can be anywhere from 1 to 60 feet across.  This fungus lives from year to year in plant debris and thatch and in the top ½ inch of soil.  The brown patch fungus (Rhizoctonial fungus) can live away from the host as a "saprophyte" (An organism, especially a fungus that frown on and derives its nourishment from dead or decaying organic matter).  Brown patch can be spread by attaching itself by mycelium (hair like growths on the fungus) to objects such as mower wheels and transferring to healthy turf grass, turf infected this way may have an elongated pattern (due to the wheels) instead of the circular pattern.

 

Conditions conducive for Brown Patch infection:

· Hot humid weather (day time temperatures over 85 degrees F and night temperatures above 60 degrees F)

· Lawns heavily fertilized with chemical fertilizers, especially those high in nitrogen and low in phosphorous or potassium.

· Poorly drained soil.

· Irrigation at night.

· Dull mower blades "chew" the blades off causing excessive damage to the blade increasing the chance of infection.

 

Prevention and elimination:

· Develop a healthy organic lawn.

             A.  Use only organic fertilizers and pesticides on lawn

             B.  Core aerate and add ¼ to ½ inch of organic compost to lawn, preferably once a year.

· Irrigate in morning so the grass blades will not stay wet over long periods of time.

· Proper mowing techniques.

             A.  Sharp blades

             B.  Proper height

             C.  Frequent mowing (never remove more than 1/3 of the blade at a time.

· If brown patch is present treat with one of the following.

             A.  Apply agriculture corn meal at the rate of 10 lbs. per 1000 sq. ft. 

             B.  Apply garlic spray

             C.  Apply solution of potassium bicarbonate