Is There a Fungus Among Us?

Brown Patch

Summer has arrived with its excessive heat, limitless sunny days, and absence of rain.  The struggle for the homeowner is deciding what is responsible for the brown sections of the lawn.  Is it the sprinklers that aren't covering well?  Is it the lawn guy’s fault because he just fertilized, broke a sprinkler, or repeatedly cuts the lawn too short?  Did someone in my family toss or leave something on the lawn causing it to turn brown?  Is the neighbor’s dog or cat squatting on the lawn?  Are there lawn bugs?  Is it bad soil?  Aliens landing?  Perhaps even a fungus?

An experienced and knowledgeable professional should be able to identify and eliminate most of the above causal agents by taking soil samples, looking at patterns, asking questions, and getting on their hands and knees to look at the soil, thatch, and leaves.  I maintain that lawn diseases are too often made the scapegoat when really something else is causing the problem.  I can’t tell you how many times we have been told that ”My gardener says that I have a fungus” when they just have dry spots in the lawn.

Make no mistake.  We do experience a good deal of disease activity on tall fescue, bluegrass, and ryegrass lawns in the summer months.  Many of these are soil borne or at least lay dormant in the soils or thatch until the proper conditions arrive.  Symptoms are usually spots or circular rings in the lawn unlike many sprinkler or insect patterns.

Brown Patch is probably the most common lawn disease in our market.  It likes hot sunny areas, ample irrigation, poor air circulation, warm nights, and late evening watering.  You can’t control the weather, but you can manage the amount, frequency, and timing of your irrigation.  Deep, less frequent watering that is done between 3-6 am is best.  The sun can then dry out the lawn and leaf blades by mid morning reducing the period of leaf wetness.  

Southern Blight is another fungus that infects the same cool season grasses during the summer.  It has sclerotia, seed like structures, that hibernate in the soils and thatch until the conditions are favorable for “germinating”.  Typically yellow to brown rings of 1-12 feet in diameter will form. We do not feel the watering schedule has a significant impact on its spread or damage.  A preventive fungicide is the key for this one.

Pythium is a water mold and it loves wet and saturated conditions for its spread and infection of the cool season grasses.  It will appear as spots of greasy matted leaves in lawns generally over watered.  This is the least common of the three and can mostly be managed with proper watering practices and use of a fungicide as needed.

We have found that prevention with fungicides is a terrific option. Some offer up to 30 days of protection in our area.  

For more information on lawns please check out our website at Fresno.WeedManUSA.com or call us at 266-1624.