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Patch Diseases

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Patch diseases cause frustrating yellow areas in your lawn. The two most common are Summer Patch and Necrotic Ring Spot. Both are caused by root-eating fungi. Your local Weed Man Madison, WI professional will be able to advise you on treatments or cultural practices that will help the turf recover!

What is Summer Patch?

Madison, WI summer patch is a root disease that commonly affects lawns with Kentucky bluegrass and fine fescue grasses. As the fungus responsible for the disease invades the lawn's roots, circular patches, around 2 - 3 inches in diameter, will begin to appear. They often start as a yellow color, turning straw-brown as the lawn disease causes the grass plant to die, and can spread to be as large as 12 inches in diameter.
Conditions Favoring the Disease
Summer patch often occurs in mid-summer when wet weather or heavy irrigation are followed by extended periods of high temperatures exceeding 82˚F. Lawns that are shaded, have poor drainage, or are compacted have a much higher chance of suffering from the disease.
Cultural practices that promote positive root growth, such as aeration, help to improve drainage on lawns suffering from compaction. Additionally, raising the height of your mower blade may lessen the extent of summer patch injury.

Weed Man Lawn Care Madison, WI Can Help!
Weed Man Lawn Care Madison, WI is here to help. Weed Man Madison, WI’s turf specialists can recognize Summer Patch disease and make recommendations to help your lawn. Weed Man Madison, WI’s specially blended slow release fertilizer applied at the right time is the first step in preventing Summer Patch. Weed Man Madison, WI’s fertilizer helps create healthy turf by slowly feeding the lawn as it needs it encouraging deep rooting systems. 

What is Necrotic Ring Spot?

  • A troublesome disease that infects lawns across WI
  • This disease is a parasitic form of plant life called fungi. Fungi live in the soil, thatch and dead leaves all year round. These fungi feed off the grass by drawing nutrients from it.
  • The disease spreads throughout the lawn in the form of spores. Wind, air, water, and humans spread these spores. (spores are minute reproductive cells) The disease may occur from year to year depending on environmental and cultural conditions.
  • The disease may be caused by improper mowing and watering. Discuss maintenance procedures with your Madison, WI Weed Man. If the lawn is put under stress the disease may occur.
  • The disease takes the form of perfectly shaped rings of yellowed out grass with healthy grass growing within the ring.
  • The grass blades appear straw yellow and die from the tip down.
  • As a result of its appearance, the disease is also referred to as "frog-eye".
  • The disease first attacks very early in the season and becomes especially visible during warm weather.
  • Necrotic Ring usually attacks sodded lawns but may also attack seeded lawns in both sun and shade.


  • Necrotic Ring is a very difficult disease to control.
  • When the disease first occurs rings may be dug out with a shovel to rid the soil of the disease spores. Remove the grass and soil to a depth of 6 to 8 inches (15-20 cm). Wash the shovel before using it again.
  • Rake the area open; fill in the hole with some potting soil to create a seed bed.
  • Overseed the area with a perennial ryegrass seed mixture and rake the area lightly. Step on the area lightly to ensure good seed-soil contact. Keep the seed bed moist for at least 21 days. 
  • If the area becomes so infected that removing the rings becomes unreasonable, correct maintenance practices must be used to control the problem.
  • First and foremost, prevent your lawn from becoming droughty. A lawn requires 1 to 11/2 inches (3-4 cm) of water weekly. According to recent theories a lawn should receive light, frequent watering to control Necrotic Ring. WATER SHOULD NOT BE APPLIED AT NIGHT. Water laying on grass plants overnight encourages disease to spread in the water droplets.
  • Mow your lawn frequently to a desirable height of 2 to 21/2 inches (5-6 cm) with a razor sharp blade.
Promoting a healthy lawn is the key to preventing Necrotic Ring from appearing. Have your Madison, WI Weed Man fertilize your lawn and advise you on correct maintenance practices to ensure a healthy disease free lawn. Fungicides are not an economical form of control. They are regarded only as a temporary control.

Fungicides only control Necrotic Ring until heavy rains wash the fungicide off the grass blade. Fungicide applications would have to be done every 10-14 days all season long and are very expensive. Weed Man Madison, WI strongly advises against the use of fungicides. Cultural control is superior and more effective.