How To Identify Diseases In Your Nebraska Lawn
Nebraska is known for hot summers, freezing-cold winters, and periods of high humidity, creating the perfect environment for a variety of lawn diseases. Typically in the form of fungal infections, lawn diseases can ravage a lawn and make your grass weak and unsightly. To help our readers, we have put together this list of common diseases to look out for so you can protect your Nebraska lawn!
Brown Patch
Brown Patch is a fungal disease caused by Rhizoctonia solani. It thrives in the warm, humid conditions typical of Nebraska summers. This disease is particularly harmful to cool-season grasses like tall fescue, perennial ryegrass, and Kentucky bluegrass. Brown Patch typically develops when nighttime temperatures remain above 65°F and the lawn is exposed to excessive moisture due to overwatering, heavy rainfall, or poor drainage.
Temperature Range:
- Nighttime temperatures above 65°F and thrives when daytime temperatures reach 80-85°F with high humidity.
The disease starts as small, circular brown patches that can expand rapidly, especially under favorable conditions. The affected grass blades display a water-soaked appearance, and lesions with a tan center and dark brown border may form. If left untreated, Brown Patch can cause significant damage by killing large sections of turfgrass.
Key Identifiers:
- Circular patches of brown, dead grass.
- Tan lesions with dark brown borders on grass blades.
- Rapid spread in warm, humid weather.
Dollar Spot
Dollar Spot is caused by Clarireedia spp. It primarily affects fine-textured grasses such as bentgrass, Kentucky bluegrass, and perennial ryegrass. This disease thrives in conditions of warm days, cool nights, and high humidity. Poor soil fertility, especially nitrogen deficiency, can exacerbate the problem.
Temperature Range:
- 60-85°F, particularly during periods of warm days and cool nights.
This disease manifests as small, silver-dollar-sized patches of straw-colored grass, hence its name. Over time, these patches may merge, forming irregular patterns of dead grass. Upon closer inspection, infected blades reveal straw-colored lesions with reddish-brown borders. While Dollar Spot rarely kills the entire lawn, it can significantly weaken the turf, making it susceptible to other stresses.
Key Identifiers:
- Small, circular patches resembling dollar coins.
- Straw-colored lesions with reddish-brown borders.
- Most active during humid conditions with nitrogen-poor soil.
Fusarium Blight
Fusarium Blight develops with the spread of fungi in the Fusarium genus. It is a destructive disease that affects cool-season grasses like Kentucky bluegrass and tall fescue. It typically occurs during hot, dry summer weather, especially on lawns stressed by drought, over-fertilization, or excessive thatch buildup.
Temperature Range:
- 80-95°F, often active during hot, dry summer conditions.
Fusarium Blight starts as small, circular patches of wilted grass, which turn tan or reddish-brown. These patches often develop a "frog-eye" pattern, with green grass in the center and dead grass surrounding it. Fusarium Blight can weaken the lawn’s overall health and reduce its ability to recover from stress, leaving it vulnerable to further damage.
Key Identifiers:
- Circular patches with a "frog-eye" pattern.
- Wilted grass that turns tan or reddish-brown.
- Typically occurs in hot, dry weather with high thatch levels.
Fairy Ring
Fairy Ring is a fascinating but problematic fungal disease caused by a variety of fungi, including Marasmius oreades. These fungi thrive in organic matter such as decaying roots or buried wood. Fairy Rings often occur in poorly aerated soils and are most visible in well-fertilized, irrigated lawns.
Temperature Range:
- Wide temperature range. Typically active during warm, moist weather, around 60-85°F.
Early in its development, Fairy Ring manifests as rings or arcs of dark green grass, sometimes accompanied by mushrooms along the perimeter. The fungi decompose organic matter, releasing nitrogen, which stimulates darker green growth. In severe cases, the soil develops a low tolerance for moisture, leading to areas of dead grass inside the ring. Fairy Rings are notoriously difficult to control and often require a combination of aeration, dethatching, and fungicide applications.
Key Identifiers:
- Rings or arcs of dark green grass.
- Mushrooms appearing along the ring’s edge.
- Dry, dead grass inside the ring in severe cases.
Rust
Rust is a fungal disease caused by various species of Puccinia. It typically affects cool-season grasses such as Kentucky bluegrass, perennial ryegrass, and tall fescue. Rust thrives in mild, moist conditions and often appears during late summer or early fall when lawns experience slow growth due to nutrient deficiencies or drought stress.
Temperature Range:
- 68-86°F, with high humidity and slow grass growth.
Rust begins as small, yellow-orange flecks on the grass blades, which later develop into powdery pustules containing orange or rust-colored spores. These spores can rub off onto shoes, pets, or lawn equipment, spreading the disease further. While Rust rarely kills the lawn, it weakens the grass, making it more vulnerable to other stresses.
Key Identifiers:
- Yellow-orange flecks on grass blades.
- Powdery orange spores that rub off easily.
- Most common during late summer or early fall.
Red Thread
Red Thread, caused by Laetisaria fuciformis, is a common fungal disease in cool-season grasses like perennial ryegrass, Kentucky bluegrass, and fine fescues. It thrives in cool, moist weather, especially in nitrogen-deficient lawns and lawns that deal with frequent rain or moisture that may wash away nutrients in the soil.
Temperature Range:
- 60-75°F, particularly during prolonged periods of cool, damp weather.
The disease gets its name from the red or pinkish thread-like structures (sclerotia) that form on infected grass blades. Patches of affected grass take on a reddish hue and may eventually die, leaving the lawn looking thin and patchy. While Red Thread primarily causes cosmetic damage, it indicates poor lawn health and the need for proper fertilization.
Key Identifiers:
- Red or pink thread-like structures on grass blades.
- Reddish patches of grass in the lawn.
- Most active in cool, moist, and nutrient-poor conditions.
Powdery Mildew
Powdery Mildew is caused by Blumeria graminis and is a common issue for lawns in shaded areas with poor air circulation. This fungal disease thrives in cool, humid conditions, often appearing in spring or fall. Standing water and compacted soil commonly lead to the development of this disease.
Temperature Range:
- 60-70°F, prefers shady areas with high humidity and cool temperatures.
Affected grass blades develop a white, powdery coating, which can spread rapidly if conditions remain favorable. Over time, the infected grass becomes weakened and may turn yellow or brown. Powdery Mildew is more of a nuisance than a severe threat, but it can detract from the lawn’s appearance and vigor.
Key Identifiers:
- White, powdery coating on grass blades.
- Yellowing or browning of infected grass.
- Most common in shaded, poorly ventilated areas.
Snow Mold
Snow Mold is a fungal disease that develops under snow cover during winter. It is caused by Typhula spp. (Gray Snow Mold) or Microdochium nivale (Pink Snow Mold). The disease becomes apparent as the snow melts in early spring. It is most severe in areas where snow remains for prolonged periods, especially if the grass was left tall before snowfall.
Temperature Range:
- 32-40°F, develops under snow cover or in cold, wet conditions in early spring.
Snow Mold appears as circular patches of matted grass with a gray or pinkish tint. The fungus damages grass blades and crowns, potentially killing sections of turf. Proper lawn care in the fall, including mowing and dethatching, is essential to prevent this disease.
Key Identifiers:
- Circular patches of matted grass with gray or pinkish coloring.
- Damage becomes apparent after snow melts.
- More severe in areas with prolonged snow cover.
Call Summit For Lawn Disease Prevention In Nebraska!
Thankfully, most lawn diseases are treatable if the damage is not too widespread, and proper lawn care can always help prevent a fungal infection. Aeration and proper irrigation are critical in the prevention of lawn diseases because most fungi thrive in moist, compacted soil. While treating diseases with fungicides can be effective, there are certain hazards that come with this method if you are inexperienced with such products.
If you think your turf may be suffering from a fungal infection, call Summit Lawns today to see the difference we can make!
