Have you noticed orange or rust-colored dust on your shoes after you walk through the lawn? Or your mower or pets suddenly covered in an orange powder?
Although this may look alarming, this is most likely lawn rust, a common disease that frequently appears on lawns during the summer and early fall. The good news is that lawn rust is typically a cosmetic problem. It rarely kills an established lawn and most lawns can recover once growing conditions improve.
what is lawn rust?
Lawn rust is caused by several related fungal species, most commonly fungi in the Puccinia genus. It primarily affects cool-season grasses commonly found in Northeast Ohio lawns.
The fungi produce yellow-orange or reddish-brown spores on the grass blades. These powdery spores easily rub off on shoes, clothing, lawn equipment and pets.
According to Purdue University Extension, rust is largely cosmetic on established turf, although a severe outbreak can weaken grass that is already stressed. Newly seeded lawns may be more vulnerable, especially when young grass loses vigor during hot or dry conditions.
why does lawn rust develop?
Rust is most common when grass is growing slowly. Conditions that can contribute to an outbreak include:
- Summer heat and drought stress
- Low soil moisture
- Low nitrogen availability
- Compacted soil
- Excessive shade
- Poor air movement
- Long periods of morning dew
- Watering late in the day or at night
Rust frequently appears during mid- to late summer as cool-season grass naturally slows its growth. Moderate temperatures, high humidity and extended leaf wetness allow the fungus to infect the grass.
This combination explains why rust can become noticeable after a period of dry summer weather followed by cooler nights, heavy dew or intermittent rainfall.
will lawn rust kill the grass?
In most established lawns, rust will not kill the grass. The disease affects the leaves and is usually more of an appearance issue than a threat to the entire lawn.
However, a heavy or prolonged outbreak can weaken turf and leave it less able to tolerate other stresses. Newly seeded lawns require closer attention because young grass can be more seriously damaged.
Rust is also a sign that the lawn may not be growing as vigorously as it should. Drought stress, inadequate nutrition, soil compaction or excessive shade may be contributing to the problem.
how is lawn rust managed??
The most effective approach is to improve the lawn’s overall health so the grass can grow faster than the disease develops.
- Water deeply in the morning. If rainfall is limited, water deeply rather than applying small amounts every day. Morning watering allows the grass blades to dry during the day. Avoid evening watering, which can extend the amount of time the leaves remain wet overnight.
- Maintain proper lawn nutrition. Low nitrogen availability can slow grass growth and make rust more noticeable. A properly timed fertilizer application may help the lawn regain vigor and grow out of the infection.
- Continue mowing regularly. Regular mowing removes infected portions of the grass blades and encourages new growth. Keep the lawn height at 3.5″ or higher. Mowing too short can add more stress to the lawn making it hard to recover.
- Temporarily bag clippings. Removing the grass clippings when a lawn is heavily affected by rust will help reduce disease severity. Once the outbreak has cleared, healthy grass clippings can be returned to the lawn.
- Address soil compaction. Compacted soil restricts root growth and limits the movement of air, water, and nutrients. Core aerations can improve growing conditions and help strengthen chronically thin or slow-growing turf.
does rust require a fungicide?
A professional fungicide treatment may be considered when an outbreak is severe, continues despite improved lawn care or threatens newly seeded grass. The fungicide suppresses the rust fungus and slows additional disease development. It does not completely eradicate the fungus from the lawn or instantly remove the orange spores already present. The orange or damaged portions of the lawn will remain visible until they are removed through mowing and replaced by healthy, new growth.
Purdue University Extension describes fungicides as remedial treatments for severe or unacceptable rust outbreaks. Purdue also recommends combining treatment with practices that encourage healthy grass growth.
For the best results, fungicide treatment should be paired with proper watering, balanced fertilization, regular mowing and temporary bagging of heavily infected clippings. These practices help the lawn grow out of the existing damage while the fungicide limits continued disease activity.
Will rust harm dogs or people?
The orange spores can make a mess, but lawn rust is not generally considered harmful to people or pets. Purdue University turfgrass specialists specifically note that it will not harm dogs.
You may still want to wipe your pet’s paws and coat after walking through a heavily affected lawn to prevent the orange powder from being tracked indoors.
how long does rust last?
Rust often begins to fade once cooler weather, adequate moisture and proper nutrition encourage the grass to grow more vigorously.
As the lawn produces new growth and is mowed regularly, the infected portions of the grass blades are gradually removed. The lawn’s color and appearance should improve as long as the underlying stress is addressed.
is your lawn covered in orange dust?
Orange grass does not automatically mean your lawn is dying. In many cases, it means the grass is stressed and growing slowly.
Custom Lawns can evaluate the affected areas, check for conditions that may be contributing to the outbreak and recommend the appropriate fertilization and lawn-care plan. Contact us if you are seeing orange powder, thinning grass or other unusual symptoms in your Northeast Ohio lawn.