Lawn Diseases- Part 1


To help eliminate many problems that cause diseases in your yard, you will need to follow a few simple rules of good lawn care. If these measures are taken and a serious disease still takes hold, chemical control may be necessary. Most diseases may be controlled with chemicals, but some, such as smut fungus, can only be controlled by planting a disease resistant grass. Analyze and identify the disease before you take any action for removal.

  • Plant a grass type that is adapted to your climate  and landscaped area.
  • Fertilize on a regular schedule that fits your lawn growth and grass type.
  • Water for long periods on a regular schedule that fits your lawn growth and grass type.
  • Mow at the proper height for your lawn. Remember that if a lawn is cut longer, it is more likely to be healthier.
  • Aerate on a regular basis. This should be done either yearly and no more than 3 times a year.
  • Power rake to remove thatch whenever needed. Thatch should be no more than ⅓ inch deep.

Recognizing common diseases in grass

Brown patch

You will see large, irregular, circular areas up to several feet in diameter. The spots are usually brown to gray and have a water-soaked appearance around the edges. These signs are usually only seen on leaves and stems. This will look the same as a fertilizer burned area. This affects centipede grass, St. Augustine grass, Bermuda grass, bent grass ryegrass, and zoysia grass.

Cultural control-Aerate and water deeply. Remove causes of excess shade. Do not overdose with Nitrogen. Power rake whenever minimum need arises.

Cottony Blight

Sometimes this disease is called grease spot blight. It can affect an area a few inches or several feet in diameter. The diseased area will be surrounded by blackened blades covered with a white or gray mildew. Dry weather will halt the disease. Most affected grasses: bent grass, Bermuda grass, ryegrass, and fescues.

Cultural control-Aerate profusely. Avoid watering heavily. Do not use excessive fertilizer.

Dollar Spot

A fungus that attacks several different varieties of grass, it kills in small spots that are 3 to 12 inches in diameter. Many spots can, however, come together to form a large dead area. Affected areas usually range in color from dark tan to light yellow. Most affected grasses: Bermuda, all fescues, Kentucky bluegrass, and ryegrass.

Cultural control- Use larger amounts of nitrogen. Aerate and water for longer periods. Decrease thatch through hand or mechanical means.

Fairy Rings

Appears as rings or arcs of dark green, fast-growing grass from several inches to over 40 ft. Fairy rings expand outward at a rate of anywhere from 2inches to 4 feet per year. Rings may spring up as a result of buried organic matter such as lumber, logs, roots, or stumps, and are produced by any one of over fifty different kinds of fungus.

Grasses affected: All grasses

Cultural control: Apply increased nitrogen to hide the problem. Aerate profusely. Keep area wet for about two weeks and mow frequently. If this does not work, replace the soil to a depth of twelve inches or more and sod.

This article and list of disease is continued in "Lawn diseases- Part 2".

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