As is the case with all fungal lawn diseases, Red Thread can quickly spread its damaging effects all across your lawn if it is not addressed. This disease, which is caused by the Laetisaria fuciformis fungus, is known for the unique-looking red strands it leaves behind in the areas it infects. Red Thread is one of the more common lawn diseases in the Kansas City area, so it is becoming increasingly important to know how to prevent and identify symptoms of Red Thread in your own yard.
Though it mainly affects cool-season grass types, Red Thread can infect all types of turfgrasses under certain environmental conditions. Tall fescue and Kentucky bluegrass are two of the more commonly afflicted turfs in our area, but L. fuciformis is also known to spread across bentgrass, perennial ryegrass, bermudagrass, and more.
Red Thread lawn disease gets its name from the reddish strands produced by the L. fuciformis fungus, which are known as sclerotia. Under close examination, the sclerotia are often described as having an antler-like appearance towards the tips of the affected grass blades, and they create the appearance of tangled red threads when observed from a distance. The sclerotia will become hard and brittle if conditions are too dry, and they will turn pink and cotton-like when wet.
L. fuciformis initially makes its presence known by damaging turf and causing small spots of tan/yellow grass to appear, similar to the effects of Brown Patch or Dollar Spot. Those spots will begin taking on a reddish or pinkish color as the sclerotia form, which is how you can differentiate patches of Red Thread from other lawn diseases.
As it spreads, you may notice cottony tufts of mycelium expanding over newly infected blades of grass, and larger areas of infection will likely appear as matted entanglements of red strands.
Lawns are most likely to see a Red Thread infection in spring and fall because L. fuciformis thrives in cool-to-moderate temperatures. Generally, temperatures between 40 °F and 80 °F will promote the development and the spread of Red Thread, with 65 °F to 70 °F being the ideal range for this particular fungus to grow. Along with the ideal temperature range, environmental conditions most conducive to the growth of L. fuciformis include prolonged rain and/or humidity and low levels of sunlight.
Red Thread is a foliar disease, meaning it does not infect the root or crown of a plant, and the damage caused by the disease is limited to the appearance of the individual grass blades. Though it does not directly kill turfgrass, Red Thread is naturally drawn to lawns that are already severely struggling due to poor nutrition and undesirable environments. Due to the unique conditions of each affected lawn, the symptoms may go away on their own after a single season, or the damage may return every spring. After repeated attacks on weakened turf, it is possible that the combined effects of Red Thread and poor nutrition could lead to dead grass.
As winter approaches, L. fuciformis goes dormant by attaching its mycelium to dead/previously infected grass. This mycelium is extremely resistant to the elements, which makes it the perfect method of overwintering for fungi. When the warmer temperatures begin to return, and if the same developmental factors are present in the following spring, the mycelium will start growing and spreading once again, and the symptoms of Red Thread will reappear.
Many of the factors that lead to the development of Red Thread in a residential lawn are also some of the leading causes of other fungal lawn infections. Because many fungi thrive under similar circumstances, your lawn may be vulnerable to all sorts of lawn diseases if certain maintenance tasks are consistently neglected. Below is a list of a few major causes of Red Thread and some easy ways you can avoid this unsightly disease.
Low Nitrogen Levels - Lawns that are under-fertilized are especially vulnerable to Red Thread. Turfgrass struggles to grow properly if it does not have adequate levels of nitrogen, among other nutrients. Using a season-appropriate fertilizer that contains proper levels of nitrogen is a quick and easy step you can take to dramatically reduce the likelihood of a Red Thread invasion. Fertilizers with nitrogen will also help your turf regenerate if your lawn is recovering from a prior lawn disease.
Excess Thatch - Red Thread is quite common in lawns that have excessive thatch buildup. L. fuciformis can survive for years after attaching itself to thatch in the soil. Reducing thatch in the soil of your lawn will create a less attractive environment for this fungus, and core aeration is a great way to dethatch your lawn. Thatch, which is a layer of organic material that has been compacted under the soil surface, can be decomposed and broken down by core aeration, making a healthier and more disease-resistant lawn for your home.
Poor Sunlight - Similar to all living things, lawns need sunlight to grow. To avoid an infection from forming across shaded areas of your lawn, you may want to consider trimming any large bushes or trees that may be blocking sunshine from reaching your turf. Adequate sunshine will help keep your lawn dry and warm the turf, both of which are factors that deter Red Thread.
Improper Watering - When it comes to preventing fungal lawn diseases, few things are as important as monitoring the dampness of your turf. Having a wet lawn during the daytime that stays damp as cooler temperatures arrive at night is a sure way to invite harmful fungi. To avoid this, water your lawn early in the morning. By watering in the morning, your lawn has the entire day to absorb the moisture and dry itself out before temperatures fall in the evening.
Improper Mowing - Several aspects of lawn mowing can lead to a fungal infection, and steps should always be taken to avoid them. Keeping your lawn at a healthy height for your grass type is vital to making sure your lawn gets enough nutrition to stay healthy; never mow too low if you are worried about lawn diseases. If your lawn is already showing signs of a Red Thread infection, you will want to make sure to clean mower blades after every use and bag grass clippings as mowing occurs. Infected grass blades being transferred via lawn mower blades is always a major factor in the spread of lawn disease.
The good news about Red Thread is that its effects are primarily cosmetic. With proper preventive and/or curative measures, lawns should be able to fight back and recover from Red Thread relatively easily. Because Red Thread may clear up on its own, and it does not affect the roots of turfgrass, fungicides are not always used (or even recommended) to treat it. Of course, every situation is unique, and some lawns may be damaged worse than others by Red Thread.
No matter what your lawn disease control needs are, Heartland Turf & Landscape can help! Whether you want to utilize our services to avoid the issues listed above, or if your lawn is ravaged by disease every season and you want to begin fungicide treatments, we have the services and expertise to help you reclaim your turf! Call us at (913) 238-9278 for more information on Red Thread, other fungal diseases, and all the ways our services can improve your lawn!
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