What is Rust in the Lawn and How to Get Rid of It

grass rust on various of blades of grass

Do your shoes look covered in Cheeto powder after walking on the lawn? Then your turfgrass may be suffering from rust (no, not the kind that forms on metal). Rust is a turfgrass disease that ruins your lawn’s cosmetic appearance, and its fungal spores get on almost everything that touches the infected grass, including Fido’s paws. 

So how do I get rid of rust in my lawn? The secret lies in a new lawn care routine.  

What is rust in the lawn?

Rust diseases aren’t caused by one type of fungus. A variety of related fungi cause rust in turfgrass. The most common turfgrass rust diseases are:

  • Stem rust (Puccinia graminis)
  • Crown rust (Puccinia coronata)
  • Stripe rust (Puccinia striiformis)
  • Leaf rust (Uromyces spp.)

Rust is mainly a cosmetic disease that ruins your lawn’s beauty, but a severe rust infection can kill your turf. 

How to identify rust on turfgrass

Orange dust on your shoes and clothes is a good sign your lawn has rust, but how do symptoms appear on the individual grass blades? Let’s take a look: 

  • The lawn appears yellow or orange when you view it from a distance.
  • Small yellow spots develop on the grass leaves.
  • As the disease progresses, the yellow spots expand into raised pustules that are yellow or orange.
  • The pustules burst and release powdery masses of spores (aka Cheeto dust). The spores are often orange, but they can also be brown, yellow, or red. 

What causes rust in the lawn?

Just like a poorly maintained garden tool rusts over time, a poorly maintained lawn can rust, too. If you’ve been skipping your lawn care chores, or even performing specific treatments incorrectly, then your lawn may be susceptible to rust disease.  

But lawn maintenance isn’t the only factor that encourages rust problems. Weather conditions also will have an impact on disease development. 

So, what could be causing your lawn to rust? Here are some conditions that encourage the disease: 

  • Rust thrives when air temperatures are warm (optimal temperature range is 68 to 85 degrees Fahrenheit)
  • Rust pathogens target lawns that are slow-growing due to environmental stressors or poor maintenance
  • Long periods of leaf wetness
  • Low nitrogen levels
  • Drought
  • Shade
  • Poor airflow
  • Soil compaction
  • Low mowing heights
  • 10 to 12 hours of dew covering the grass

How to get rid of rust in the lawn

Steel wool won’t cut it for this kind of rust. You’ll need to make some changes to your lawn care routine if you want to remove this turfgrass disease. 

The key is to reverse the environmental factors that made the lawn so attractive to rust in the first place. For example, if your watering habits left your yard wet for long periods, you’ll need to adjust your watering routine so the lawn dries faster. 

Ready to have regular shoes again with no Dorito dust on them? Here’s what you’ll need to do: 

  • Raise the mowing height. Mowing the lawn too short often leads to exposed stems and the turf struggling to photosynthesize (cutting this low is known as scalping the lawn). 
  • Improve your fertilization regime. Rust fungus favors an environment with low nitrogen levels. 
  • Amend irrigation practices. The best time to water the yard is in the early morning before 10 a.m. This allows enough time for the lawn to absorb the moisture before the afternoon sun evaporates the water. Avoid watering in the evenings; otherwise, the water will cling to the leaf blades overnight and encourage leaf wetness. 
  • Improve air circulation and increase sunlight by trimming and pruning landscape plants near affected areas. 
  • Remove grass clippings after mowing to help prevent the disease from spreading. 
  • Aerate the lawn to relieve compact soil. 
  • Fungicides aren’t always necessary for rust control. Why? Because they aren’t a suitable replacement for good lawn care practices. But when a severe rust infection persists despite cultural measures, fungicides can be helpful. Always use fungicides according to the product label. 

How to prevent lawn rust (and other turf diseases)

Rust is similar to many other lawn diseases (you mean there are other turf diseases? Yikes!) –– it strikes lawns that are weak and poorly maintained. 

Delaying yard work is tempting, but it could result in something strange growing on your lawn. And who wants to deal with that headache? It’s best to stick to a good lawn care routine so that you don’t have to sweat over a turf-killing fungus in the future. 

If disease continues to recur despite lawn care measures, consider applying a preventive fungicide. Fungicides are typically more effective as a preventative treatment than a curative one. 

The healthier your lawn, the more resistant it will be against disease. And the better you maintain it, the healthier it will be. Here are 15 lawn care treatments that will boost your lawn’s health and strength: 

  • Remove leaves and other debris from the yard. A thick layer of leaves on the yard will prevent the turf from photosynthesizing. Plant debris also makes excellent real estate for dormant fungus. 
  • Mow your lawn regularly (and correctly). Never cut off more than ⅓ of the grass blade at a time. Stick to your grass type’s recommended mowing height –– you might scalp your lawn if you mow too low. But if you cut too high (or not at all), then your yard may invite snow molds. 
  • Leave behind grass clippings. Grass clippings are a healthy mulch for the lawn and decompose quickly. However, don’t leave behind diseased grass clippings; otherwise, the disease might spread. 
  • Perform proper irrigation practices. The best way to promote a healthy root system is to water less frequently and for long periods. Watering too often and for short periods encourages a weak root system. The best time of day to water the lawn is before 10 a.m. 
  • Invest in a sprinkler system. If sticking to an irrigation schedule proves difficult, an automatic sprinkler system may be just what you need. 
  • Plant grass seed that’s disease-resistant and suitable for your lawn. Talk to a local lawn care professional about disease-resistant cultivars. Many advanced lawn grass varieties are bred to combat diseases. You’ll also need to determine whether warm- or cool-season grass is best for your yard. 
  • Test your soil. A healthy lawn will struggle to grow without nutrients. Perform a soil test to see what nutrients your soil is missing and learn how to make amendments. 
  • Fertilize your grass. A soil test will often reveal how much fertilizer your lawn needs. Prepare a fertilization regime that meets your lawn’s needs without going overboard (too much fertilizer is bad for the environment and will even attract some diseases). 
  • Aerate compact soil. Compact soil prevents water, oxygen, and nutrients from accessing the lawn’s root system. Aeration relieves compaction by creating holes in the ground.
  • Remove thatch that exceeds ½-inch thick. Do you ever notice a buildup of dead plant debris between the soil’s surface and your turf? It’s called thatch. A thin thatch layer is good for the lawn, but a thick layer may weaken your lawn and harbor dormant fungi. 
  • Overseed the lawn. Encourage a dense, green lawn with routine overseeding. 
  • Remove existing weeds. Your grass should spend its energy growing healthy, not combating weeds. A weed invasion forces your turf to compete for space, sunlight, nutrients, and moisture. Remove existing weeds with a post-emergent herbicide or pull them by hand. 
  • Apply pre-emergent herbicide. If weeds continue to invade your lawn, apply a pre-emergent herbicide to block them from growing. 
  • Control grubs and other pests. Grubs love to snack on your lawn’s root system, which weakens your turf as a result. 
  • Spread compost across the lawn. Compost is a nutritional organic fertilizer for the soil. You can apply compost by raking it across the lawn as a top dressing or spread compost tea with a sprayer.

How does rust spread in the yard?

Grass rust spreads via its spores. Walking through infected areas will disturb the pustules and cause them to release the orange spores that cling onto your shoes or Fido’s paws. Wind, grass clippings, and lawn equipment also can spread the spores. 

The rust spores are produced in spring, summer, and fall and survive the winter in living plant tissue. 

What grasses are susceptible to rust?

Rust diseases occur on all turfgrasses. However, your lawn is particularly susceptible to rust if you grow Kentucky bluegrass, perennial ryegrass, tall fescue, Zoysiagrass, or St. Augustinegrass.  

What if I can’t identify the disease in my lawn?

Correct identification of lawn disease is essential if you want your control measures to be effective. Why? Because the control methods that work for one lawn disease might not work on another. If you misidentify the fungus, your control efforts may prove futile and allow the disease to progress. 

Sometimes identification requires the eye of a professional. If you can’t identify the disease, consider contacting a diagnostic lab or turfgrass pathology lab for help. These labs specialize in diagnosing infected turf and are typically located at state universities.

What other turf diseases can infect my grass?

Your lawn may be susceptible to several fungal diseases, including: 

Don’t let a fungus steal your fun

Removing a fungus from the lawn is hard work. It often calls for significant changes to your lawn care routine and hours in the sun. And when you’re dealing with a severe infection, you might even rake or mow the weekend away. 

If you don’t want to hand over your valuable free time to a fungus, hire a local lawn care professional to remove the disease for you. Not only can a professional remove a fungus from the lawn, but they also can prevent future outbreaks from occurring. Leave the fungus to the pros, and don’t let a fungus steal your fun (unless you love mycology or mushroom hunting).  

Main Photo Credit: Scot Nelson | Flickr | public domain

Jane Purnell

Jane Purnell is an artist, writer, and nature lover. She enjoys teaching readers about the importance of eco-friendly lawn care, integrated pest management, biodiversity, and sustainable landscaping.