Why do grass turn yellow? Here is the solution to the mushroom problem

Brown and yellow spots in the lawn: Water is not always lacking / Why do grass turn yellow? Here is the solution to the mushroom problem

Snow mold, red thread or witch rings are fungal diseases that can ruin your lawn. How to recognize, fight and prevent the diseases.

In the lawn that was just completely green, small mushrooms are suddenly growing everywhere – individually or in groups. Or coin-sized spots form, such as in dollar spot disease. Above all, too intensive or incorrect care can be the reason for eyesores in the lawn. With a few tricks, you can prevent a fungal infestation and prevent it from coming back.

Mushrooms often grow in a specific spot

Mushrooms appear particularly often in those places in the garden where a tree or bush previously stood. Some of the remains of the dead plant are still in the ground and are rotting there. This is an ideal breeding ground for the organisms.

What is not allowed with mushrooms in the lawn

The fungi are usually not harmful. If you simply mow them off, however, there is a risk that the spores will spread even further in the lawn. That is why it is advisable to cut them out before mowing. After removing the fungus, it is important to clean the tool thoroughly.

Chemical agents are also not a solution for combating fungal infestation in the home garden, as they are not permitted.

Red thread leaves reddish spots in the lawn

If, for example, light brown irregular patches spread across the lawn and the stalks have pink-colored branches, then the lawn is probably affected by red thread. The disease occurs, among other things, as a result of waterlogging, but it can also be due to an unbalanced supply of nutrients. The fungus spreads particularly well in warm, humid temperatures.

To fight the disease, it is necessary to strengthen the lawn. It is often sufficient to provide the grass with a long-term nitrogen-based fertilizer. In the long term and as a preventive measure, it is important to scarify the lawn sufficiently. If the lawn thatch is not removed, it promotes fungal infestation.

Witch rings are formed by mushrooms

Another lawn disease caused by fungi is the so-called witch rings. Ring-shaped discolorations form from dead stalks in the lawn or small mushrooms grow in circles in the lawn. The rings are usually lined with dark grasses, which grow particularly well because they use the ammonium compounds secreted by the fungi as a source of nitrogen. The circular shape arises because the fungi spread evenly outwards from an infection site. The diameter can be several meters. Up to 50 different fungi can be responsible for the damage.

To prevent this from happening, the lawn should always be sufficiently fertilized and, if necessary, scarified in the spring, advises the plant protection service of the North Rhine-Westphalia Chamber of Agriculture.

Anything that strengthens the lawn will prevent the rings from appearing. You should also mow the lawn – even where there are mushrooms. This would remove the mushroom fruiting bodies and make it harder for the mushrooms to spread using spores.

If a “witch ring” has formed, garden owners should know that the so-called mushroom mycelium in the soil often has a water-repellent effect, the experts explain. This can lead to the grasses drying up, even though they are actually watered sufficiently.

In order to prevent drying out, the area around the “witch ring” should be punctured with a spade to a depth of 25 centimetres, loosened and then thoroughly watered, advises the plant protection service. This way, excess water could kill the mushrooms.

Dry soil favors dollar spots

You can tell if your lawn has been infested with dollar spot disease by the small, light-colored, coin-sized spots (one to two centimetres). In the early stages, these are reminiscent of the size of a dollar coin. Over time, however, the spots can grow up to 15 centimeters in size. Only the stalks are affected by the fungus called Sclerotinia homoeocarpa.

You can also recognize the disease by the light-colored constrictions on the stalks, which look like straw. Depending on the cutting height of the grass, large round patches are formed that can be easily distinguished from a healthy lawn. The infestation is promoted, among other things, on very dry soil and by a lack of nitrogen and potassium. The danger is particularly great when it is warm during the day and rather cool at night.

If your lawn is infested, you should water it thoroughly once or twice within the next ten days. This is enough to rehydrate the soil. Do not water too often, otherwise you create ideal conditions for renewed or further fungal infestation. It is best to water in the morning so that the lawn can dry faster. If the infestation is severe, the affected areas must be reseeded.

To prevent and combat the disease, you should not mow the lawn too short, give it balanced fertilizers and be careful when watering. Avoid too long dry periods – water your green space regularly.

Our photo show gives you a quick and easy overview of what you need to consider when caring for your lawn.

Recognize and combat snow mold

While red thread and dollar spot occur mainly in the summer and witch rings all year round, snow mold is most common in spring and autumn. The lawn disease can be recognized by grey, greasy, damp spots in the lawn, which expand as the infestation progresses. Snow mold tends to develop in damp, cool weather on felty lawns.

Even if the name suggests otherwise: the fungal disease can also break out without snow. Clippings or leaves can also impede air circulation and thus ensure that the floor dries poorly. Snow mold can be recognized by grey, damp patches that appear on the meadow.

This can be prevented by regular and balanced fertilization. An oversupply of nitrogen should be avoided. Horn meal should therefore only be used with caution. It is also advisable not to walk on the lawn when there is snow. This also prevents typhula rot, which occurs under comparable conditions with a similar damage pattern. However, the spots are rather grey-brown and orange outgrowths can be seen on the culms. Scarifying helps with both diseases.

Infested by pests

In addition to fungi, pests can also be to blame for the brown and yellow spots in the lawn. For example, the larvae of grubs, which attack the roots of the blades of grass, causing them to wither. It is therefore important to recognize and combat the larvae and, preferably, the parents early on.

Caution: sprays must not be used for this. It is better to use nematodes against the larvae and to lure the natural enemies of the grubs into the garden.

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