10 common lawn diseases with picture | Instructions on how to combat it

Grasses infested with lawn rust seem as if the ravages of time are gnawing at them. Yellowish and dark pustules colonize the leaf tips. Seen from a distance, the green area resembles a yellow-brown spotted carpet. Without countermeasures, the fungal infection spreads over the entire length of the stalk. Fatally, the spores are so robust that they multiply equally under snow and in summer heat.

Causes:

• Imbalanced water supply
• Persistent rainy weather

Combat:

• Sprinkle lawns when the ground is noticeably dry
• Water in the early morning to allow the grass to dry
• Apply lawn fertilizer in spring and autumn

Reaching for the fungicide is neither necessary nor useful. In dry weather and with a balanced supply of nutrients, the disfigured green space regenerates within a few weeks. By regularly mowing the stalks by a maximum of a third and sweeping away the clippings, you prevent the further spread of rust fungi in the lawn.

Rotspitzigkeit (Laetisaria fuciformis, Corticium fuciforme)

A lawn can suffer from red tipped spots at any time of the year. The fungal infection develops its highest infestation pressure in warm and humid weather with temperatures between 15 and 25 degrees Celsius. Classic symptoms are the eponymous red leaf tips, followed by a reddish, antler-like fungal network. Furthermore, irregular, straw-yellow, dried-up areas appear on the green area.

Causes:

• Inadequate nutrient supply (primarily nitrogen deficiency)
• Too high humidity

Combat:

• Fertilize the lawn in a balanced way in spring and summer
• In addition, give fertilizers with a high concentration of potassium in autumn
• Mow regularly (cut no more than a third of the length of the stalk)
• Scarify at least once a year

As long as your lawn suffers from red tipping, please dispose of the clippings in the household waste. Thanks to this care, the fungal spores cannot spread any further in the garden. Chemical fungicides are not permitted for home and allotment gardens. The sooner you diagnose and treat the infection, the better your lawn can regenerate on its own.

Snow mold (Microdochium nivale)

The common lawn disease occurs in winter, hidden under the blanket of snow. If the snow allows a clear view of the green area, silvery shimmering stalks catch the eye. Gray and brown spots with sticky leaves quickly form. Sometimes brown-gray patches of lawn have a pink border.

Causes:

• Fungal infection on weakened lawn
• Nitrogen oversupply in autumn
• Compacted, waterlogged soil

Combat:

• Scarify or aerate once or twice a year
• Lawn sand
• Fertilize with potassium emphasis in autumn

By optimizing the care of your lawn, weakened lawn grasses can recover from spring. The regeneration is strengthened by rising temperatures, so that the fungi are displaced by vigorous grass growth. Where your lawn won’t drift by itself, repair bald spots with fresh seeds.

Hexenringe

Witch rings are a well-known phenomenon on green spaces, which were said to have magical powers in the distant past. In truth, it is a striking presence of hat mushrooms. At the beginning, dark green rings form, the diameter of which increases from year to year. Sooner or later the subterranean fungal plexuses break through and numerous hat-shaped fruit bodies sprout.

Causes:

• Nutrient-poor subsoil
• Decomposition of old cuttings and organic substances by fungi

Combat:

• Pierce the digging fork several times into the witch’s ring
• Slightly lift the sward with the mushroom mesh
• Then water the areas intensively
• Sanden pushes back witch rings
• Repeat the measure over several weeks

As a preventive measure, you should not leave any clippings on the lawn. To prevent hat fungus pathogens from finding attack surfaces, remove lawn thatch and organic substances by scarifying them regularly in spring. You strengthen the resistance of noble grasses by applying a special lawn fertilizer in spring and not using conventional complete fertilizers. A potash-emphasized autumn lawn fertilizer at the end of August / beginning of September optimizes winter hardiness and the immune system.

Leaf spot disease (Drechslera poae, Curvularia)

The common lawn disease owes its name to whitish-yellow to brown spots on leaf blades. A characteristic symptom of the fungal infection are yellow leaf tips, as if the entire lawn had dried out. The disease occurs predominantly at temperatures between 10 and 30 degrees Celsius.

Causes:

• Lawn weakened as a result of incorrect maintenance
• Mowing too deep

Combat:

• Mowing according to the golden one-third rule (1/3 of the stalk height)
• Consistently sweep away cuttings and leaves
• Water regularly when dry
• Scarify or aerate, sand and fertilize every spring

The aim of the control strategy is to improve the maintenance program. A lawn can only recover from leaf spot disease over the long term if ideal framework conditions are created. On the other hand, spraying fungicides at certain points or for a limited period of time does not work.

Powdery mildew, powdery mildew (Erysiphaceae)

Grasses in the shade are primarily affected by powdery mildew. Where warming rays of the sun are rare, damp lawn grasses dry slowly. Permanently moist leaf blades offer the fungal spores ideal attack surfaces to settle down and expand explosively. Mealy-white, cotton-wool-like spots are a significant distinguishing feature of powdery mildew, which increasingly develop into a covering covering the leaf surface.

Causes:

• Too high a lawn cut
• Waterlogging
• Warm and humid weather
• Nitrogen excess, potassium deficiency
• Zu hoher pH-Wert (idealer Wert liegt bei 6 bis 7)

Bekämpfung:

• Kranke Rasenstellen ausharken, neu einsäen mit Saatgut für Schattenrasen
• Lichtzufuhr verbessern, beispielsweise durch Auslichten schattenwerfender Gehölze
• Stets mähen nach der Ein-Drittel-Regel
• Jedes Frühjahr vertikutieren und sanden
• Stickstoff-Überdüngung und Kalium-Mangel vermeiden
• Nur dann kalken, wenn ein pH-Wert-Test den Bedarf anzeigt

Im frühen Stadium verhelfen Sie Ihrem Mehltau-geplagten Rasen zu altem Glanz mit einem bewährten Hausmittel. Vermischen Sie je 1000 ml mit 125 bis 250 ml frischer Milch und füllen die Lösung in eine Sprühflasche. Behandeln Sie die Grünfläche zwei- bis dreimal wöchentlich mit Milch-Wasser, bis die Krankheitssymptome verschwunden sind.

Dollarflecken-Krankheit (Sclerotinia homoeocarpa)

Coin-sized, dried-up areas of lawn signal that a lawn suffers from dollar spot disease. The clear demarcation from healthy green is unmistakable. The fungal infection occurs primarily in summer on short-mowed green areas such as ornamental lawns, soccer fields or golf courses. The telltale, white network of mushrooms can be clearly seen in the presence of morning dew or high humidity.

Causes:

• Too short a lawn cut
• Fungal susceptible seeds
• Excessive watering
• Compacted soil

Combat:

• Comb out the sick spot
• Reseeding with largely resistant varieties of ostrich grass (Agrostis)
• Mow the lawn no shorter than 3.5 to 4.5 cm
• If it is dry, water in the early morning
• Scarify and sand once or twice a year
• Apply potassium fertilizer in late summer and autumn

According to the database of the Federal Office for Consumer Protection and Food Safety, fungicides for combating dollar blotch are not approved. In any case, lawn experts are registering an increasing build-up of resistance to spray agents that are permitted in the commercial sector. By scrutinizing and optimizing the care of your lawn, you will reduce its susceptibility to most diseases.

Schwarzbeinigkeit (Gaeumannomyces graminis)

The disaster begins with yellowish to orange-colored spots. The initially 5 to 10 centimeters small damaged areas eventually reach a diameter of 100 centimeters and more. Fatally, the fungal infection spreads to the roots of lawn grasses, which turn dark brown to black.

Causes:

• Too high pH
• Vulnerable to drought stress or waterlogging
• Nitrogen overfertilization

Combat:

• Rake out damaged areas and repair with lawn plaster
• Measure pH
• Liming at a pH value greater than 7
• Fertilize balanced with lawn fertilizer
• Aerate and sand compacted subsoil

Lawns near grain fields are explicitly endangered by black-leggedness. The pathogens are not picky and like to be carried into the garden by wind and rain to attack grasses. The better a lawn is cared for, the stronger its defenses against fungal invaders.

Slime mold (Mycetozoa or Eumycetozoa)

Slime mold in the lawn draws attention to itself in different colors. The variants range from yellow to orange to purple. The fruiting bodies settle on the stalks in the form of drop-shaped pustules. The infection usually occurs in summer when warm, humid weather dominates.

Causes:

• Persistent rainy weather in summer
• Organic substances on the green area, such as cuttings, mulch, root residues

Combat:

• Scarify, re-sow healthy seeds, sand
• If the infestation is stubborn, peel off the lawn and re-sow

So that you don’t have to bother with slime mold in the lawn in the first place, please consistently remove grass clippings and leaves. Planned fertilization, watering, liming and sanding will thank you for the noble grasses with their reliable resistance to lawn diseases. On a vital, lovingly cared for lawn, fungi have a hard time finding a target at all.

Root burn, root rot (Pythium ultimum)

When a newly laid lawn weakens, it is the victim of damaged seeds. Root burn is one of the most common lawn diseases that give gardeners a headache after planting a new one. Light, sunken areas can be seen on the green area. Characteristic are limp, drooping stalks with a slimy consistency. On closer examination it is noticeable that the root neck is darkly discolored. Furthermore, the noble grasses can easily be pulled out of the earth. In rainy weather, a white mycelium appears visibly.

Causes:

• Damaged seeds of poor quality
• Overfertilization
• Lawn thatch
• Drought stress

Combat:

• Scarify or aerate the lawn
• Reseeding with high-quality, premium-quality seeds
• Nutrient supply with special lawn fertilizer
• Regular watering in case of summer drought

As a rule, freshly laid lawns should not be scarified or aerated in the first few years. If, on the other hand, you are affected by root burn as a result of poor quality seeds, this measure is recommended from the second year onwards. The scarifier combs out the damaged stalks to make space for fresh lawn seeds of harmless quality.

Conclusion
Ten common lawn diseases lose their horror when the gardener is familiar with characteristic symptoms. This guide not only names the causes, but also has the right picture for every disease. This enables you to make the correct diagnosis at an early stage and initiate effective control measures. Comprehensible instructions explain how you can arm your lawn for the silent fight against fungal pathogens.