Fungi in the lawn are usually not a serious threat, but they can certainly disrupt the appearance of the lawn. Below we will introduce you to the most common fungal diseases that can affect lawns and which countermeasures are suitable.
Mushroom species
When it comes to fungi in the lawn, a distinction is made between fungal diseases and cap fungi. Cap fungi, which sometimes appear very suddenly and in large numbers on the lawn in late summer and autumn, are usually completely harmless to the lawn, while fungal diseases can kill entire areas of the lawn. In most cases, fungal diseases are not really critical or worth combating immediately. Many of them will soon disappear on their own when the weather conditions change.
Here is a brief overview of a selection of fungal diseases and cap fungi that commonly occur in lawns:
Fungal diseases:
| Lawn rust | Red-tippedness | Snow mold | Dollar spot disease | Slime molds | |
|---|---|---|---|---|---|
| Appearance features | rusty-looking, yellowish-orange spots on the grass leaf blades, mottled overall lawn appearance | Dried-looking grass islands, reddish leaf tips | Light gray to light brown spots in the lawn, sticky leaves after snow melt | Small dry spots in the lawn | Small, greyish-whitish, black or yellow, slimy deposits in the lawn |
| Educational conditions/at what times of the year | Hot, humid weather in summer | Nutrient deficiency, all year round or especially in summer when the humidity is high | Damp, moderately cold weather in winter | In summer on lawns that are permanently kept very short | In summer when the weather is warm and humid |
| Countermeasures/Prevention | Waiting for dry weather/Regular mowing, watering and fertilizing | Fertilize, do not dispose of grass cuttings in the compost | Regular aeration by scarifying and sanding, fertilizing in autumn | Rarely, but water thoroughly, aerate well (scarify, sand), potassium-based fertilization in early summer | No essential countermeasure required due to harmlessness. Scarify, fertilize and water regularly as a preventative measure |
| Swindles | Navellings | Tintlings | Kahler Krempling | Alkaline Rötling | |
|---|---|---|---|---|---|
| Appearance | Small, round mushrooms with thin-fleshed fruiting bodies in brown to white | Small, brown mushrooms with umbrella-like, centrally sunken, coarsely laminated fruiting bodies | White mushrooms, acorn-shaped in the young stage, later bell-shaped fruiting bodies, blackish in color with age | Brown-reddish to yellow mushrooms with medium-sized lamellar caps, relatively fleshy | Light brown, sometimes white or red mushrooms, high stem, flat, sunken to humped umbrella |
| Edible? | Some species edible | Most species inedible | The Crested Tintling in particular is an excellent, mild-tasting edible mushroom | No – poisonous | No – poisonous |
| Inclination towards witch rings | Especially the carnation swindler | No | No | No | Yes |
Excursus
Witch rings on cap mushrooms
In a certain case, cap mushrooms can still damage the lawn, despite their growth behavior not directly affecting the lawn plants: namely with witch rings. A witch's ring, also commonly referred to as a witch's circle, is a circular or semicircular formation of fungal fruiting bodies. This happens when the mycelium grows out at the same speed in all directions due to a lack of nutrients in the middle.
A witch ring expands over the years and, if left unchecked, can lead to discoloration and dry damage to the lawn. Of the cap mushrooms, only around 80 species tend to form witch rings. The species found in garden lawns include, for example, the carnation moth, the alkaline red mushroom and the meadow mushroom.
Remove fungi in the lawn properly
Fungal diseases
Many fungal diseases are not really a threat to the lawn and disappear on their own when the weather changes. Even a period of humid, warm, drizzly weather will eventually come to an end. When it gets drier again, grass rust, red tip and slime mold usually disappear quickly and snow mold is also pushed back as soon as it gets warmer and drier again in spring.
The best way to combat dollar spot disease is to water less often and more extensively and deeply. In this way, the lawn can be supplied with sufficient moisture, but still has the opportunity to dry off well in between.
Basically, you can counteract fungal diseases in the lawn primarily by preventing them. The best way to do this is through the usual care measures that keep the lawn resilient and he althy. So you should regularly:
- Aerification by scarifying and sanding
- Water
- Fertilize
- Mowing
Aerification
How intensively and often you have to scarify or sand depends on the site conditions and the soil properties. A heavy clay soil in a shady location is naturally much more prone to constant wetness and acidification, which on the one hand creates favorable conditions for fungi and moss and on the other hand weakens the lawn grass and makes it more susceptible to infections. When taking these measures, it is best to follow the visual signals of your lawn.
Water
Watering is a sensitive matter in terms of preventing fungus. On the one hand, the lawn needs an adequate supply of water for its he alth, but on the other hand, it becomes susceptible to fungus if it is too wet. Therefore, only blow it up during long dry periods in summer, ideally in the early morning hours or in the evening when the sun is no longer directly shining on it.
Fertilize
For basic lawn he alth, it is recommended to give it a long-term fertilizer once in spring and again in late summer. To avoid snow mold in winter, it is important to use a potassium-based fertilizer in the fall.
Tip
During the period of a fungal disease, mow around the infected areas in the lawn first and cut them last. This will prevent the spores from spreading to areas that are still he althy. Dispose of the clippings in the household waste until the fungal disease has subsided.
Mushrooms
If a homogeneous, clean lawn appearance is important to you, excessively sprouting fungi are of course annoying. Most species found in garden lawns appear as small brown, gray, white to orange mushrooms. However, cap mushrooms do not penetrate the grass plants with either their underground mycelium or their fruiting bodies, so they are really only a cosmetic problem.
With cap mushrooms, it often happens that many mushrooms suddenly appear in the lawn overnight, so to speak. That's no reason to worry at first. Only when they form so-called witch rings can discoloration and dry damage occur.
Suitable control measures are as follows:
- Depriving the mushrooms of their nutritional basis
- Tear open mycelium with digging fork
- Earth Exchange
Withdraw food base
If you want to permanently remove cap mushrooms, you should carry out continuous pruning and scarifying care. It is best to mow regularly with a grass catcher and reduce the thatch by scarifying in a grid pattern. This deprives the mushroom mycelia of their nutritional basis. In addition, it helps to loosen and aerate the soil by sanding.
But be careful: mowing alone doesn't help at all with cap mushrooms. On the contrary: they only promote the spread of the spores, while the actual fungus, the underground mycelium, remains undamaged. With the result that even more fruit bodies shoot out of the ground.
Specifically damaging mycelium
You can also specifically target the fungal areas: arm yourself with a digging fork, pierce the ground several times in the fungal areas and lift it slightly. This can rupture the fungal mycelium and cause it to die
Earth Exchange
Soil replacement helps with many fungal diseases
In the case of clearly demarcated mushroom areas, especially in witch rings, soil replacement can also be an option. To do this, remove the top 30 cm of the soil layer, fill it with fresh soil and reseed with the highest quality grass seed possible.
Tip
In order not to spread the cap mushroom spores unnecessarily, it is advisable (in addition to disposing of the clippings in household waste) to remove the fruiting bodies by hand before mowing. If it is an edible species, collect something for lunch at the same time.
Fungicides
In most cases you should not and cannot work with fungicides. For many fungi that occur in garden lawns, no chemical agent is permitted. This is particularly true for the cap mushroom species. Apart from that, it is generally not advisable to use chemical agents, herbicides and fungicides to combat undesirable phenomena in the garden. In doing so, you not only upset the biological balance of your garden but also that of the wider environment.
Causes of fungi in the lawn
The causes of fungi in lawns and beds are relatively diverse and are not just limited to favorable growth conditions for the fungi. Certain site conditions and care habits can also make the lawn simply too susceptible. The main causes of fungal diseases and annoying cap fungus accumulations are as follows:
- Lawn and air permanently too wet
- Too little light
- Matted, poorly ventilated lawn
- Soil acidification
Too wet
As with all fungal diseases on plants, conditions that are too humid are also the decisive cause of the development of fungi in the lawn. If it is constantly too wet, fungi feel particularly comfortable on it. Warm, humid phases in summer with stagnant air are particularly responsible for some fungal diseases. Long-term temperatures of 20 to 30°C and persistent, drizzly precipitation or damp weather in winter create optimal conditions for various fungal diseases.
Cap mushrooms also like it moist. Especially under trees, with which many species form mycorrhitic symbioses and where moisture lasts longer, the risk of fungal growth is increased.
Too little light
Lack of light does not necessarily promote the spread of fungi, but it weakens the lawn and thus increases its susceptibility to fungi. Under tall, dense-crowned trees, the lawn grasses cannot form a strong turf and become holey and permeable to dreaded disturbing combinations such as fungi plus moss and fungi plus weeds.
Matted Lawn
Scarifying prevents fungal diseases
If a dense thatch of lawn has formed due to years of neglected care without regular scarifying, watering, mowing and fertilizing, the lawn no longer gets any air, which weakens it and makes it less competitive. On the other hand, the thatch forms an ideal breeding ground for fungi. As a prevention against fungi and also in the case of existing fungal infestation, grid-like scarification is helpful, with which the lawn thatch is combed out.
Soil acidification
If many fungi sprout from the ground despite good lawn care with sufficient aeration, watering and fertilization, this may be due to acidification of the soil. Check if the pH is below the lower limit of 5.8 with a simple soil test. If this is the case, balance the value according to the package instructions with lime.
At what times of the year do fungi appear in the lawn?
Mushrooms are primarily associated with autumn. However, this association primarily refers to the world of edible mushrooms. When we talk about fungal diseases in the lawn, summer is the more important season. This is because many of the common fungal lawn diseases develop in warm, moist conditions. Fungi that are less of a disease but can disrupt the appearance of the lawn - especially cap fungi - actually appear mainly in autumn. Isolated fungal diseases only occur in winter, even under a blanket of snow.
Avoid care errors
watering too much
Regular watering is a perfectly good care measure for a he althy, well-maintained lawn. But you shouldn't overdo it either. If the lawn doesn't get a chance to dry out between spraying, grass rust and red tip have an easy time, especially when temperatures are in the 20s. So only water your lawn during long dry periods and, if possible, in the early hours of the morning, when the sun is not yet scorching down on the grass, but its first, soft rays can dry it gently.
mulching too much or incorrectly
Mulching the lawn is generally highly recommended. If you mow frequently and leave the clippings lying around, all the nutrients remain in the lawn soil and can be recycled. This means you need to add less additional fertilizer. The activity of microorganisms living in the soil is also stimulated and the turf is compacted, so that typical combinations such as mushrooms plus moss and mushrooms plus weeds have fewer chances.
Research has shown that mulch mowing makes the lawn significantly stronger and more vital than conventional mowing (in which the clippings are collected in the lawnmower's catcher basket).
In order for the advantages of mulching to be realized, the method must be used correctly. This means: Above all, you have to mow regularly and at short intervals (preferably weekly during the vegetation phase). When mowing, the lawn should also be as dry as possible and free of other organic material such as fallen leaves. Clippings that are too long or wet and clumped with leaves can also clog the lawn and lead to a lack of light and air. This in turn weakens the lawn and increases its risk of infection.
Overfertilization
Regular fertilization is recommended for a strong lawn that is more resistant to fungal diseases. But you can also be overly generous with the fertilizer application - when it comes to fertilizing, the rule always applies: less is more. Especially if you fertilize with too much nitrogen in the fall, this can quickly lead to snow mold in the winter. Long-term fertilization twice is ideal for a lawn, once in spring and once in autumn. In the fall you should use a high-caliber preparation.
Frequently asked questions
Which mushrooms in the lawn are edible?
The clove moth (Marasmius oreades) is edible
Of the cap mushrooms most commonly found in lawns, the swindles, only a few species are edible. In addition, because of their measly size, most of them are not very suitable for a proper, substance-rich mushroom ragout. However, the real garlic swindle is often used as a seasoning mushroom, especially in France, for example in dried form. The spicy-sweet-tasting clove moth can also be eaten, which is actually the best way to combat its damaging effects on the lawn. For example, it is particularly good in mushroom soups.
Tintlings are also excellent edible mushrooms and have more substance due to their size. They can be eaten raw in salads or fried in a pan. But you should harvest them in good time before the hat opens up and secretes the black ink liquid that gives it its name for self-digestion.
If you're lucky, perhaps the kings of edible mushrooms, meadow mushrooms, will settle in your garden lawn. The versatility of their usability does not need to be explained in more detail. However, extreme caution is advised because of the slight risk of confusion with the highly poisonous green death cap mushroom.
Which mushrooms in the lawn are poisonous?
When it comes to cap mushrooms, a general distinction is made between edible, inedible and poisonous species. There are also representatives of all of these categories among the species that are more common in garden lawns. The Kahler Krempling and the Alkaline Rötling are poisonous.
The Kahle Krempling contains, among other things, hemolysins and hemagglutinins, which can lead to severe, possibly fatal, gastrointestinal inflammation. However, the poisons are destroyed by intensive heating. In addition to the poisons, the Kahle Krempling also contains a dangerous allergen that can lead to the formation of antibodies, which can also be fatal.
The Alkaline Rötling is also poisonous, but its pronounced ammonia smell is not exactly inviting to try.
Whoever has certain deciduous trees such as oaks, copper beeches, chestnuts, birches or hazels growing in their garden may also be home to the green death cap mushroom, which enters into a mycorrhitic symbiosis with these trees. As most people know, this mushroom is one of the most poisonous species of all. The amatoxins and phallotoxins contained in its pulp can lead to liver failure and death even in small doses. The poisons are not destroyed even by heating.
The most important distinguishing features between the green death cap and the similar-looking but highly edible meadow mushroom are, on the one hand, the lamellae: these are pure white to greenish in the green death cap, white-pink in the meadow mushroom, later brown and finally black. On the other hand, in contrast to that of the meadow mushroom, the stem of the green death cap is surrounded by a thin, slightly greenish skin sheath.
Are there home remedies for fungus in the lawn?
Using home remedies in the garden is generally not particularly advisable. Many remedies that you have in the household often have more ecologically problematic side effects than harmful benefits against undesirable phenomena in the garden. No special home remedies have proven effective against fungi.
