Red Thread Disease

Red Thread Lawn Disease Treatment

Red-Thread-Lawn-Disease-TreatmentRed Thread is one of the most common lawn diseases seen in the UK and it’s likely to affect your lawn on a yearly basis (provided you don’t take particularly good care of it).

But don’t worry, it’s not as big a deal as you might think.

Even though it will make your lawn look a little poorly (by changing the colour of the grass blades), the disease won’t kill it entirely.

It only affects (and sometimes kills) the blades of grass, not the plant and its roots. So the only problems it will cause are related to the aesthetics of your lawn and not its overall health.

That being said, it will cause the lawn to look unpleasant for a good few weeks so you want to do all you can to reduce the risk of Red Thread lawn disease, or at least catch it early and treat it correctly to prevent a shabby looking lawn.


Even though high humidity is the main cause of Red Thread, there are many other things that can cause it as well, most of which are related to poor lawn maintenance practices.

These include:

This is why those that take minimal care of their lawn are more likely to experience Red Thread in their lawn on an annual basis. A well-maintained lawn could avoid the disease altogether, or at the very least only see minor symptoms of Red Thread.


You will most likely see Red Thread appear during summer and early autumn as this is when humidity is at its highest.

It is a fungus known as Laetisaria fuciformis and it can take one of two forms. It can be seen as pinkish mycelium clusters or, more commonly, antler shaped threads known as sclerotia.

Make sure you are careful when identifying Red Thread. If you are doing so during the summer period, than make sure you don’t get it confused with drought, which can look similar to Red Thread at first glance – both turn your turf into a grey-brown colour.

It can also be confused with dollar spot, pink snow mold and pink thatch. All of these diseases tend to occur at the same time of year as Red Thread.

If you take a closer look at the grass blade, you’ll notice small red straws sticking out from the grass blade, which over time will grow and become more visible.

You don’t necessarily need a magnifying glass to see this, but it will be much clearer if you do so. Look out for the clusters of mycelium or the antler-shaped growth to confirm it is in fact Red Thread.

The patches caused by Red Thread usually grow to about 7.5cm to 25cm but they can grow even larger. In severe cases, these patches start to join leaving large unsightly areas on your lawn.

Resistant and susceptible grasses

Red Thread disease does not affect all grasses and some are more susceptible to the disease.

Most at risk are bentgrass, ryegrass, Kentucky bluegrass, annual meadow grass and particularly red fescue. These are the cool-season grass varieties. More resistant grasses include “Pennant” perennial ryegrass and “Bilart” and “Claudia” fine fescues.

So, if you are planning on re-seeding or re-turfing your lawn you may want to take this into consideration.


As I said above, those that are most likely to see Red Thread as those that don’t take the best possible care of their lawn.

Therefore, in order to prevent the disease from appearing in your lawn at all, you need to KEEP it in the best condition possible.

To do so, follow the steps below:

  • Applying nitrogen to the affected area will often be sufficient to control the disease. The best way to do this is with sulphate of ammonia. Apply at a rate of 15g per square metre.
  • Scarifying the turf (Best Lawn Scarifier and Rake Reviews) will remove thatch and moss and will increase aeration, which will reduce the threat of Red Thatch.
  • Poor drainage and compacted soils can be alleviated by forking or by the use of a solid or hollow tined aerator, which also reduces the threat of Red Thatch.
  • If you have a lawn with Red Thread disease, make sure you dispose of the grass clippings you gathered whilst mowing separately – don’t mix it in your compost. This reduces the amount of fungus present to re-infect the lawn. hollow tined aerator
  • Ensure your mower blade is sharp. A dull lawn mower blade will bruise and damage the grass blades. This reduces the health of the grass and leaves it more susceptible to disease. If you are looking for a new lawn mower, you can see the best mowers I have reviewed by clicking on this link – Best Lawn Mower Reviews.
  • Add iron. Treat the lawn with iron in all but the summer months to toughen the grass up. It will help to reduce moss growth and make the lawn stronger and less susceptible to fungus and disease.
  • If you’re fertilising on a regular basis and still receive Red Thread, then this is just the lawn telling you that it is still running a little low on nutrients.
  • Enrich or replace the soil. If fertilising is not doing the trick it could mean that the soil quality is poor. It might be necessary to add compost and additional nutrients to the soil. In extreme cases, it might be necessary to replace the soil.
  • You could apply a fungicide to treat the affected area, but you’d need to do this before it spreads, which can be difficult to judge. If you do plan to use a fungicide, look for one that contains carbendazim or benomyl. Trifloxystrobin is the main ingredient available to treat Red Thread disease. This should be a last resort and only if you have a really bad case of the fungus. Do not use chemical control when the lawn is frozen or during extremely dry conditions. The treatment can be applied after mowing but you will need to leave at least 2 days after the lawn has been treated to allow for adequate absorption. Application is very easy where the soluble sachet is mixed with water in a sprayer, allowed to stand for 2 minutes until the water soluble bag dissolves, once mixed it is ready to be used on your lawn.

Red Thread Lawn Disease Treatment Video

If you decide to use professional services, for one off treatment this is not going to be too costly. However, if you plan on using them on a regular basis, likely to be needed annually, this could mean the cost will escalate pretty quickly.

Not only that but by applying a fungicide you are not giving the lawn a chance to build up a resistance to the disease, which makes it more likely to return year on year. You are simply treating the symptom and not the underlying cause.

So, for the long-term health of your lawn, you are better off following my advice above to enrich the soil, maintain the lawn and treat the disease. Prevention is always better than cure so a well-maintained lawn is the best way to avoid or reduce the risk of the dreaded Red Thread disease.

Proper lawn maintenance is likely to take a little more work, but it will certainly save you time in the long-run and give you fewer problems to deal with. Not mentioning the beautiful and lush lawn you and your family will enjoy.

Hope you found this article informative. Below I have included a link to other related articles that you may find interesting. Why not visit us on the EasyLawnMowing website where you will find lots more blogs and garden tool reviews to help you with achieving that perfect lawn.

Lawn Care for Beginners – More Tips!!

The Best Way to Cut Your Grass

How to Top Dress Your Lawn



Lawnmower Product Expert, Reviewer and Author at | 01284 615144 | | Website | + posts

As a seasoned expert in the field of garden power tools, I have dedicated over a decade to working with and reviewing a wide variety of lawn mowers. My extensive experience has allowed me to gain a deep understanding of the benefits and limitations of different types of mowers and garden tools.

Over the years, I have honed my skills in writing informative articles and creating helpful videos for various blogs and publications. This has given me the ability to not only recognise what makes a good lawn mower, but also to help you choose the perfect garden tool for your specific needs and requirements.

With my wealth of knowledge and expertise, I am confident that I can provide you with valuable insights and recommendations when it comes to selecting the right lawn mower for your lawn. So, whether you're looking for a battery cordless, electric, petrol, or robotic mower, you can trust in my expertise to guide you towards the best option for your garden.

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