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For many people, a beautiful, dense lawn is just as much a part of the garden as a well-tended hedge or a garden pond with lively residents. Numerous lawn diseases can cloud the green area with unsightly spots or even lead to the loss of entire sections over a long period of time, which have to be reseeded. If the lawn is sick, you need to look at the damage to identify the disease and then take action to treat it.

Lawn diseases from A - Z

Identify and take action to treat

If your lawn no longer looks attractive and does not improve even after intensive maintenance measures, it could be diseased. At first glance, diseases cannot be distinguished from classic deficiency symptoms such as yellow-brown spots or bald spots. On closer inspection, however, the damage pattern helps to identify the diseases more precisely in order to be able to take appropriate treatment measures. The big advantage: Lawns usually suffer from a manageable number of diseases that are easy to recognize. Below you will find an overview of the typical lawn diseases that make your lush lawn difficult to cope with.

tip: Of course, you shouldn't be surprised at a depleted lawn if, for example, you, your children or pets use it for playing or sports. The grasses of a usable lawn often appear a bit exhausted, but withstand the stress sufficiently.

Lawn diseases from A - D


This disease appears from spring to autumn and is caused by thatched lawns, overloading, a lack of nutrients, dryness or permanent wetness. In addition to the red-brown spots, the anthracnose can be recognized by outgrowths that resemble thorns and are very noticeable. At first glance, the disease appears like drought damage, and for this reason many gardeners overwater. However, you should take the following measures to combat anthracnose:

  • mow thoroughly
  • increase soil permeability
  • absolutely avoid dryness or waterlogging

Avoiding lawn thatch is very important. This can be combated by intensive care of the lawn. After mowing, you should compost the lawn clippings and, apart from this care step, regularly work the lawn with a rake.

leaf spot disease

This fungal disease is one of the more harmless lawn diseases and is mainly triggered by poor conditions. Small spots of white or yellow color appear here at 10 °C to 30 °C. Above all, waterlogging or mowing too deep are among the triggers of the disease. Regular mowing of a maximum of one third of the blade length, good lawn fertilization and irrigation are recommended measures. Be sure to remove the lawn clippings after mowing to prevent thatch from forming.

Dollar spot disease (Sclerotinia homeocarpa)

This disease is similar to snow mold, but only occurs at temperatures above 25 °C and comparatively cool nights. The causes for this are usually a lack of nutrients, drought and high stress by humans and animals. The symptoms are:

  • straw-colored spots up to ten centimeters in diameter
  • when damp, a fungal network forms

You should also pay attention to the correct fertilization here. Lawns survive dollar spot disease very well if they are given adequate nutrients again. The soil here is usually too dry and must be regularly supplied with sufficient water. Nevertheless, this should be permeable. If necessary, improve the soil permeability, which is made possible by scarifying or aerating.

Lawn diseases from E - H

powdery mildew

Even powdery mildew is one of the lawn diseases and can be recognized by the typical mealy coating. Lawns become ill because of a poor location in the shade, waterlogging or improper care. It can occur all year round as long as the temperatures are between 0 °C and 30 °C. The only thing that really helps here is improving light conditions and soil permeability. Alternatively, you can provide your lawn with shade-resistant species.


This fungal disease is known as summer fusarium because the typical half rings of light-colored stalks only appear at temperatures above 25 °C. Causes are either lawn thatch, waterlogging or neglect of maintenance. The worse the infestation, the redder or browner the stalks become. Adjust lawn maintenance to address these imperfections. No worries. Fusarium is one of the lawn diseases that can be treated fairly easily.

witch rings

Witch rings are among the diseases with multiple types. However, they have one thing in common: All three types of witch rings develop cap fungi that are clearly visible. The following are the symptoms of each type:

  • 1st type: Dark green rings followed by fungal growth and dying grasses
  • 2nd type: Rings in dark green, followed by fungal growth on lush lawns
  • 3. Type: Mushrooms in rings are formed, lawn is not damaged

The ring-shaped mushrooms are triggered by organic residues in the soil, which decompose and at the same time form a solid network of fungi. If it is now dry for a longer period of time, cap fungi develop from the fungal network in the soil, which mainly occurs on soils with a lot of sand and without nutrients. Water the lawn extensively and remove the fungus by replacing the soil.

Lawn diseases from K - R

crown rust

This is one of the diseases caused by two different rust fungi:

  • Orange rust fungus
  • Brown rust fungus

According to the name, the crown rust can be recognized by spore deposits on and between the stalks, which are kept in the corresponding color of the fungus species. In addition to these, light yellow spots also appear. You have to be particularly careful during the summer, as the fungi get onto the lawn as spores and spread there. From mid-autumn, the lawn will recover if it hasn't been badly damaged by then. High loads and drought stress can also lead to this. The following measures will help to combat the rust fungus:

  • Thoroughly rake the lawn
  • dispose of raked grass in household waste
  • reseed the bare spots
  • mow at regular intervals
  • let the lawn rest
  • fertilize effectively

red point

Red thread is another disease that occurs due to too much moisture and a lack of nitrogen. Laetisaria fuciformis and Corticium fuciforme are the fungi that cause your lawn to become diseased and immediately indicate red thread through characteristic symptoms:

  • Culms discolored brownish or straw yellow
  • Formation of a red fungus lichen
  • this resembles an antler in shape

You can fight these fungi particularly effectively if you administer a little more nitrogen and reduce this amount from autumn. As a result, the plants do not get the idea of using more nitrogen than is necessary and thereby leaching the soil. It is essential to water sufficiently so that the plants do not suffer from drought stress.

Lawn diseases with S

slime molds

Slime molds are created in the same way as witch rings, except the mushrooms stay in the ground. They can only rarely be recognized superficially by drops on the culms in the following colors:

  • violet
  • yellow
  • orange

Soil replacement and a good nutrient supply are also recommended here.

snow mold

Snow mold is a disease caused by the fungus Microdochium nivale. This can be recognized by the following symptoms:

  • brownish spots about three centimeters in diameter
  • can reach a diameter of up to 30 centimetres
  • off-white to pink fungal plexus at the edge
  • Stains appear slimy-moist

In extreme cases, the spots overlap and thus cover large areas. Snow mold is triggered by over-fertilization with nitrogen in autumn, waterlogging, or damp layers of leaves, mulch or snow. The necessary temperature is between 0 °C and 8 °C, but can even be as low as -20 °C to over 30 °C, i.e. all year round. As soon as you notice the spots, you should aerate or scarify the lawn. You should also mow at regular intervals, remove the lawn clippings and fertilize with more potassium and less nitrogen towards autumn.


Blackleg damage is as follows:

  • brown to black roots
  • spots about four inches across
  • Spots are yellow, orange, or reddish
  • can overlap
  • Period: spring to autumn

If you discover spots on the lawn that appear in the colors mentioned above, you should carefully pull some grasses out of the soil in the affected areas. Then check if the roots are black or brown. In this case, we are dealing with blackleg, which occurs due to too high pH values, lack of nutrients, dryness and waterlogging. Take appropriate measures based on the condition of your lawn. If you want to lower the pH value, preferably below 7.0, the following remedies can be used:

  • Oak Leaf Compost
  • coniferous earth
  • Softwood Mulch
  • coffee grounds
  • sulfur

Lawn diseases with W

root burn

Root burn is one of the diseases that often affects newly planted lawns, as they are heavily used in the first few weeks. Only with extremely poor maintenance can root burn occur in well-established areas. Symptoms are light-colored patches with slimy stalks that can be easily pulled out of the ground. When pulling out, pay attention to the neck of the roots, because they should be dark in color. Good care of the lawn with sufficient nutrient supply and good watering helps here. High-quality seed also works well against root blight.

root crown rot

Root collar rot is very similar to snow mold, but the damage is much more pronounced and can affect the entire lawn within a short period of time. Root neck rot, which is caused by the pathogen Typhula incarnata, can be recognized by light brown to brown spots with a diameter of up to 50 centimeters.

Even 100 centimeters under layers of snow or permanently moist mulch. These can overlap. The disease mainly strikes in autumn or early spring at temperatures around 0 °C. The big difference to snow mold is the stalks, which are not slimy and moist, but dry like paper. Root collar rot is treated the same way as snow mold.

tip: Root collar rot is just one of the names for this disease. It is also listed under the term gray snow mold or typhula rot.

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