Recognizing Lawn Diseases and What to Do

lawn diseases

If the curb appeal of your home or business is declining because your turf grass is looking a bit puny, you may have to put on your plant detective hat and go to work. To identify lawn diseases, you need to take a systematic approach to diagnose the problem before you can properly treat your grass.

The Grounds Guys® can help walk you through a little green detective work so you can restore your lawn to health. Check out these pointers:

A good plant detective asks questions first.

  • What type grass do you have? Lawn diseases tend to attack specific types of grass, so if you know what type grass you have, you may be able to rule out some possibilities.
  • What are the symptoms? Do you see bare patches, overall yellowing of the grass or round or irregular patches that are dead or dying?
  • How long has the problem been there? Did you notice the problem just last week? Last month? Last year? Or is it a new condition?
  • Is it localized in one area of your property, or are there other areas similarly affected? Do you notice the same problem in other areas of your landscape?
  • Is it spreading? Since you noticed the problem area(s), is it getting bigger/spreading out?
  • Have you recently sprayed chemicals or applied fertilizer on your lawn? Chemical burns can injure turf grass, so it's important to use the right products and apply them properly.
  • How do you water your lawn – and when? You can invite lawn diseases without knowing it by improperly watering your lawn.

Identify common lawn diseases by appearance.

  • Small, 3-inch-round patches of yellow or brown grass

    • Susceptible turf: warm- and cool-season turf grass species
    • Favorable conditions: warm days, cool nights, heavy dews, nitrogen deficit
    • Round patches may look cottony in the morning dew
    • Suspect “dollar spot” fungus
    • What to do: apply lawn fertilizer that contains sufficient nitrogen according to soil-test recommendations, keep grass mowed regularly, apply fungicides
  • Medium, 5- to 10-inch round patches of brown grass

    • Susceptible turf: cool-season turf grass species
    • Favorable conditions: temperatures below 80 degrees F, heavy rainfall; fall through spring seasons
    • Grass leaf blades rot at the soil level
    • Suspect “brown patch” fungus
    • What to do: don’t supply too much nitrogen, raise mower height, apply fungicides
  • Large, 3- to 25-foot patches of brown grass

    • Susceptible turf: warm-season turf grass species
    • Favorable conditions: temperatures above 80 degrees F; heavy rainfall; spring and fall seasons
    • Grass leaf blades die from the top down
    • Suspect “large patch” fungus
    • What to do: don’t supply too much nitrogen, raise mower height, apply fungicides
  • Irregularly shaped brown or straw-colored patches

    • Susceptible turf: Bermuda, St. Augustine, Centipede
    • Favorable conditions: high soil pH
    • Suspect “take-all patch” fungus
    • This disease is more common on sandy soils, although it can occur on all soil types
    • What to do: correct soil pH, don’t overwater lawn
  • Dark green “halo” ring in your grass, often with mushrooms in the ring after a rainfall

    • Susceptible turf: all turf grass species
    • Favorable conditions: decomposing organic matter, such as tree roots, in the soil
    • Rings range in size from a few inches to 50 feet in diameter
    • Suspect “fairy ring” fungus
    • What to do: prevention is the best treatment – keep your lawn dethatched, aerated, properly watered and fertilized

All lawn problems are not caused by disease. Insects, insufficient (or excessive) fertilization, and even pets can cause your lawn not to perform to its potential. If you’re unsure how to diagnose the problem with your lawn, call on The Grounds Guys. We’ll help green it up again by restoring it to health.