A lawn can be affected by various diseases and conditions, the development of which is primarily related to climatic conditions. Early diagnosis of a lawn disease or condition can substantially help limit potential damage. This way, adequately caring for your lawn becomes ecological as well as economical.
A lawn is maintained by sowing and topdressing bare areas, watering and flattening the lawn with a lawn roller if there is a presence of harmful insects and by choosing one of our fertilization programs to maintain a thick and healthy lawn.
1. Anthracnose
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Symptoms
- Yellowish-bronze irregular-shaped patches on the lawn that vary from 2 inches to several feet in diameter.
Appearance
Mostly in the spring and late-summer on areas that are poorly drained. It peaks in very hot and humid conditions (28°C +).
Cause
Anthracnose (Colletotrichum cereale). Anthracnose of turfgrass is a foliar disease or a basal rot of the lower stem found under many climatic conditions. Anthracnose foliar damage appears as irregular yellow or bronze patches of a diseased lawn surface. Symptoms on individual plants first appear as yellow or red lesions on the oldest (outermost) leaves, then progress to a damage of younger leaves and shoots. Anthracnose basal rot symptoms vary depending on the grass species affected. On annual bluegrass, symptoms appear as irregular bright yellow patches. Affected bentgrass turf typically appears as irregular red or bronze patches and rarely appears yellow. On individual plants affected with anthracnose basal rot, a dark brown or black color is present at the base of the plant. Anthracnose is likely to occur when plants are growing slowly (during periods of hot and cold temperatures), during overcast periods, and in high humidity conditions.
Prevention
- Choose one of our fertilization programs, which will keep your lawn dense and healthy.
- Keep your lawn height at a minimum of 3 to 3.5 inches.
- Do not mow a wet lawn.
- Aerate the lawn.
2. Downy Mildew
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Problem
- Presence of a powdery white substance on the lawn.
Symptoms
Patches of lawn that have a powdery white substance on grass blades.
Appearance
Throughout the season.
Cause
The disease is usually associated with poorly drained or over-watered areas. Spores of the fungus-like organism (Sclerophthora macrospora) move via free water. Powdery mildew can appear quickly on a lawn, mainly in shady areas and more frequently during cloudy or overcast periods.
Prevention
- Clear areas that are very shady, if possible.
- Topdress and overseed (with seeds specifically for shaded areas) the affected patches that are sparse with grass.
- There is no fungicide that can control this disease.
3. Snow mould
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Problem
- Presence of grayish or pinkish patches on the lawn.
Symptoms
Grayish or pinkish patches, 3 inches to 1 foot in diameter, that appear on the lawn.
Appearance
In winter on a lawn surface that is not frozen or in the spring, while the ground is thawing and the snow continues to melt.
Cause
Snow mould is a type of fungus and turf disease that damages or kills grass typically in late-winter, especially when snow is slow to melt. If the lawn is healthy, the mould, which resembles a grayish intertwined spider web, will disappear quickly once the lawn is raked. The damage, if any, is minimal. If, however, the lawn is in poor condition, the grass in the affected areas will die, leaving bare patches behind.
Solutions
- The last mow before winter must be done well before the first frost and the grass should be left at a height of 2.5 to 3 inches so that the lawn is protected from frost. It is essential to remove grass clippings after the last mow of the season in order to allow the lawn to breathe.
- Never mow the lawn after the first frost, so as to maintain the ideal height.
- Aerate your lawn.
- Topdress and overseed the affected areas in the spring.
4. Fairy rings
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Problem
- Ring of dark green grass.
Symptoms
The appearance of a dark green zones 2 inches to 1 foot in size that form circles of 2 to 15 feet in diameter. Mushrooms may also appear after it has rained.
Appearance
All throughout the season. Between the months of May and September, depending on atmospheric conditions. Mushrooms may appear as well.
Cause
Fairy rings also known as fairy circles or elf rings. They are usually noticeable after heavy rains when tan mushrooms appear in a ring-shaped pattern or during regular weather when circular or semi-circular areas of dead/dying turf appear. These areas have a margin of darker green turf just next to them. These darker areas are due to the fungus releasing nitrogen. As the rings develop, they grow outward and down – the fungi can extend down into the soil several feet. Fairy rings are spread either by spores or infected soil.
Prevention
- Choose one of our fertilization programs, which will keep your lawn dense and healthy.
- Water your lawn regularly (once a week).
- Aerate the lawn.
- Keep your lawn height at a minimum of 3 to 3.5 inches.
Control
- Keep your lawn height at a minimum of 3 to 3.5 inches and remove and dispose of infected grass clippings.
- Dig up the affected areas and replace the soil and grass.
5. Rust
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Problem
- Red powdery patches.
Symptoms
Grass that yellows and dries out, followed by the presence of scorched patches.
Appearance
From May to October, peaking in autumn or in persistently humid conditions (shaded areas, too much watering, lingering dew or poor drainage, etc.).
Cause
Rust is a fairly common lawn disease caused by fungus. Rust usually appears in shaded areas first, during warm humid weather. The fungi symptoms of this lawn disease begin as tiny yellow spots on the grass blades. These spots become elongated and eventually rupture into clusters of rust-orange spores that give the disease its name. When touched, the powdery dust-like rust spores leave a colour a lot like the fine particles of rust from metal. Rust spores are tiny and very lightweight. They can be carried long distances by the wind, which means that even the best kept lawns can be infected.
Prevention
- Choose one of our fertilization programs, which will keep your lawn dense and healthy.
- Keep your lawn height at a minimum of 3 to 3.5 inches.
- Do not overwater.
- Aerate the lawn.
6. Dollar spots
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Problem
- Presence of round spots on the lawn.
Symptoms
Clearly delimited discoloured spots that are green to brown in colour and 2 to 5 cm in diameter, reaching up to 15 cm. In the case of a strong attack, spots may converge. Affected areas clearly stand out from remaining healthy lawn. A spider web looking mould appears on the lawn when the humidity level is high.
Appearance
Spring and autumn, during the lawn’s main growth period.
Cause
Dollar spots (Sclerotinia homeocarpa).
Detection
The grass stem dries out from the middle. The mould (mycelium) can also produce a toxin that blocks the root system, which causes the plant to quickly dry out.
Prevention
- Choose one of our fertilization programs, which will keep your lawn dense and healthy.
- Keep your lawn height at a minimum of 3 to 3.5 inches.
- Water regularly (once a week).
Control
Topdress, overseed and add potassium.
7. Necrotic ring spots
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Problem
- Presence of yellow rings on the lawn.
Symptoms
Circular patches that are 6 inches to 1 foot in diameter, within which a small patch of green grass can often be found.
Appearance
All throughout the year.
Cause
Caused by the fungus Leptosphaeria korrae, in its advanced stage the damage takes the form of rings or crescents of dead grass. Cool wet weather promotes its growth in spring and fall, but the dry hot summer reveals its arcs and rings more blatantly by attacking the roots.
Prevention
- Choose one of our fertilization programs, which will keep your lawn dense and healthy.
- Water often during dry periods.
- Keep your lawn height at a minimum of 3 to 3.5 inches.
Control
Dig approximately 2 inches outside the rings, removing between 6 to 10 inches in depth and making sure to dispose of the soil and grass removed. Topdress and sow new grass seed or lay down sod strips.