Garden Advice

Lawn Diseases In the UK – Identification, Causes, and Treatment

A lush, green lawn can make any garden look more inviting and appealing. After all, wouldn’t you love to spend a sunny summer day lounging outside in your beautiful garden with a refreshing drink?

Well, your luxurious afternoon can easily be spoiled by a bunch of patchy grass that looks three seconds away from meeting its maker.

Knowing what has taken over your turf and what’s causing it is an excellent first step in treating it. That’s why we’ve prepared this guide on 10 of the most common lawn diseases in the UK. We’ll help you identify them and give you helpful tips on how you can handle each one.

So, if you:

  • Are noticing patches of dry or dead grass in your lawn;
  • Want to be able to identify different types of lawn diseases;
  • Want to know how to treat and prevent turfgrass diseases;

Then read on! This post will answer all your questions.

10 types of lawn diseases to look out for

There are quite a few diseases of lawn grasses you might encounter. While you can prevent most of them with proper turf care, that’s not always enough. So, you might find yourself battling a bunch of dried patches of grass, even if your lawn is well-maintained.

So, let’s take a look at some common lawn diseases (and some less common ones), what causes them, and how you can combat them successfully.

Brown patch

Seeing large patches of brown grass in your lawn in mid or late summer? You might be dealing with brown patch.

This disease mostly affects cool-season grasses but can also target some warm-season varieties – zoysiagrass, for example. Tall fescue and ryegrass are at a higher risk of being severely damaged by brown patch.

  • Appearance
    Large, irregular brown patches of grass.
  • Cause
    Fungus (Rhizoctonia).
  • Treatment
    Prevention with proper lawn care, or fungicides for extreme cases.

Appearance

Brown patch disease manifests as large, round, irregular spots of brown-yellow grass. They can vary greatly in size, being as small as 5 cm (2 in) or as large as 60 cm (1 ft). When inspecting the grass blades within the patch, you’ll notice irregular, tan-coloured spots with a darker brown ring around them. On humid mornings, you might see a fluffy, cotton-like material (mycelium) on the leaves.

This disease only affects the grass blades and won’t cause the roots any trouble. Affected blades will likely stay upright, but change colour.

Cause

Brown patch disease is caused by a single type of fungus. It can stay hidden in the ground for quite a while before making an appearance. This fungus is quite resilient and can sometimes survive for years, even during winter, waiting for the perfect conditions to strike.

Usually, this disease appears when the temperatures are high and the air is humid, meaning your lawn is most at risk in mid to late summer. During this time, the weather is consistently warm, even during the night. A prolonged period of rain can also help the fungus spring into action.

Heavily fertilised and watered lawns are also more susceptible to brown patch, as well as those that haven’t been cared for properly. Poor air circulation and soil drainage, compacted soil, and other symptoms of a neglected lawn can make it easier for brown patch to appear.

Treatment

While you can’t control all the conditions needed (weather rarely cares about your problems, after all), you can do your best to prevent this lawn disease. All you can really do is take good care of your lawn and hope for the best. Here are some good practices:

  • Fertilise properly.
    Don’t go overboard with fertiliser and skip this lawn care step on hot, humid days.
  • Water early.
    If possible, water the lawn earlier in the morning – this will let it dry out well enough by the evening.
  • Provide good air circulation.
    Aerating and dethatching are good practices that shouldn’t be neglected.

While spots affected by brown patch can spring back to life without the help of chemicals, sometimes the case can be too severe. In these situations, you can apply a fungicide.

Experts don’t recommend this as a universal solution, though. If you decide to resort to chemicals, you might want to consult a professional.

Dry patch

Is your grass dying in patches? The first question you should ask is, obviously, “Did I forget to water the lawn?” Examine the soil – if it’s bone-dry, try watering. If it absorbs the moisture, then you’re all good and probably just need to water more. However, if the soil won’t budge, letting the water just roll off it, then you’re likely dealing with dry patch.

This is another lawn disease in the “patch” family, albeit a bit of an enigma. In the case of dry patch, the problem is in the soil, not the grass itself.

  • Appearance
    Patches of dried, dead grass with bone-dry soil underneath.
  • Cause
    Unknown, speculated to be fungus or changes in the soil.
  • Treatment
    Prevention with proper lawn care, chemical intervention, or soil replacement.

Appearance

When dry patch appears, the grass in your lawn will start to die off in patches of various shapes. First, the blades will turn a darker green, then brown. Apart from dead grass, you’ll also find arid soil underneath that won’t let water penetrate it at all. You might notice these symptoms first appearing during dry spells.

While grass can also start drying out due to hot weather, it will usually bounce back after a rainy day. If you’re dealing with a case of dry patch, even a good amount of rain won’t save your grass from kicking the bucket. So, inspecting the soil is crucial when diagnosing this type of lawn disease.

Cause

We still don’t quite understand what causes dry patch disease, only that the soil becomes essentially water-repellent. Experts speculate that this might result from fungal growth, where soil particles get covered in waterproof chemicals. Another possibility is that some sort of change happens in the soil, either physical or chemical, causing it to repel water.

Some symptoms of poor lawn maintenance can also make the soil more susceptible to dry patch – soil compaction and thick layers of thatch are among them.

Treatment

The best thing you can do is take good care of the grass to try and prevent dry patch from tormenting your lawn in the first place. Some steps you can take are:

  • Scarify the lawn.
    Don’t let a thick layer of thatch accumulate – scarify your lawn, preferably in late spring or early autumn.
  • Prevent compaction.
    Aerating the lawn will help you avoid compaction while providing good water penetration and air circulation.
  • Feed properly.
    Make sure you fertilise the lawn properly to ensure the grass roots are healthy and sturdy.

If dry patch does end up appearing, you’ll have a more difficult task on your hands. There are a couple of things you can try to fix the issue.

First, try spiking the problematic area well and watering. You don’t need to go overboard – just water a little bit every day for a while to see if the soil will accept it eventually.

If this doesn’t work, you might need to resort to a chemical wetting agent. This is a product specifically designed to deal with dry patch by helping the soil absorb moisture. You’ll probably have to treat the lawn once a month for at least 3 or 4 months, though.

And, if none of these methods work, the only option left will probably be to replace the affected soil altogether.

Take-all patch

If you have a bentgrass lawn (or a mixture that includes it) and you notice the grass starting to die off in patches, we have bad news – you might be dealing with take-all patch.

This lawn disease hides away in the soil and affects bentgrass exclusively, targeting its roots and killing the grass.

  • Appearance
    Round patches or rings of red, brown, or yellow dying grass.
  • Cause
    Fungus (Gaeumannomyces graminis).
  • Treatment
    Sowing resistant grasses, soil cultivation, lowering the soil pH.

Appearance

Take-all patch appears as circular spots of dying grass. When it affects the turf’s roots, the blades start turning a red or yellow colour, then brown as the grass begins to die.

It can take years for this lawn disease to manifest. Once it does, it will keep reappearing yearly in the right conditions, with the patch growing by around 7.5 cm (3 in) every year.

Cause

The culprit behind take-all patch is, once again, a fungus. This one hides away in the soil, and it’s still uncertain exactly what makes it appear. While it’s present in most UK soil, you have no reason to worry about it.

Unless you’ve chosen to turf your lawn with bentgrass, of course.

Take-all patch can do a great deal of damage in certain conditions – moist soil, temperatures between 12 and 18°C, and soil pH above 7 can mean your lawn is at risk. Sandy soils and shallow roots also make this disease more destructive.

If the temperatures fall outside of the fungus’ preferred range, take-all patch can gradually disappear. But that doesn’t mean you’re safe – on the contrary, it’s just lying in wait. Once the conditions become favourable again, it will spring back up.

Treatment

This can be a severe lawn disease, we know. Unfortunately, if you’re hoping that fungicides will save the day, you’ll be sorely disappointed.

There are no fungicides available to domestic clients that can deal with take-all patch. Some companies might offer to deal with the disease for you, but since there are quite a few restrictions on fungicide use in domestic properties in the UK, you might want to double-check their credibility.

When it comes to take-all patch, the best course of action is prevention. And the best prevention method is simply avoiding bentgrass. Of course, that’s not always an option. So, here are some things you can do to try and prevent this lawn disease, or at least make it milder.

  • Take proper care of your lawn.
    Healthy grass with deep, strong roots will have an easier time recovering from take-all patch.
  • Try lowering the pH levels.
    If you manage to keep the soil pH below 6, you’ll see improvement. You can do this with an acidifying fertiliser.
  • Replace the turf.
    If the disease has already killed your lawn and you’re going to replace it, you’ll want to adjust the pH and cultivate the soil (15-30 cm from the top) before laying new turf. Otherwise, the fungus will just infect the new roots, too.

Dollar spot

This lawn disease often appears in summer and autumn, and is usually quite recognisable due to its – you guessed it – dollar-like patches. It’s fairly similar to brown patch in appearance, though spots caused by dollar spot are a lot smaller. Still, if you’re not familiar with the differences, you can easily confuse the two.

  • Appearance
    Small, round patches of pale grass.
  • Cause
    Fungus (Sclerotinia homoeocarpa).
  • Treatment
    Prevention with proper lawn maintenance, or fungicides.

Appearance

If dollar spot takes over, you’ll start noticing small, light patches in the grass, where the blades look almost bleached. The spots themselves can merge and form larger patches if growing closer together, making identification slightly more difficult. Upon closer inspection, you can find small, tan spots with a reddish-brown ring on the grass blades.

Sometimes, the patches can appear sunken, which can help you differentiate between dollar spot and brown patch, where the grass remains upright. And, as with other fungi-caused diseases, you might see white mycelium on dewy mornings.

Cause

Once again, this is a disease caused by a fungus that naturally occurs in lawns. Usually, you shouldn’t have any troubles with it, but if the conditions are favourable, it can spring up and wreak all kinds of havoc.

Dollar spot won’t affect all kinds of grass equally – lawns with lots of fescue grass are its favourite, though it can also target bentgrass or annual meadow grass.

Several things can contribute to the appearance of dollar spot: lawns mowed too short, high humidity and moisture, and poor air circulation are among them.

Treatment

While you can rely on fungicides to treat this lawn disease, you’ll likely be able to avoid it altogether with some good lawn care practices.

  • Prune trees and shrubs around the lawn.
    Improving air circulation and reducing shade will help the lawn dry out quicker, lowering the risk of dollar spot appearing.
  • Water properly.
    To avoid constantly wet grass, water less often, but more thoroughly.
  • Provide good lawn care.
    Aerate compacted spots of soil, remove built-up thatch, don’t overfeed the grass, and don’t mow too short.

Rust disease

Rust is one of the oldest lawn diseases out there and, luckily, is one of the easiest to recognise. It often appears in late summer or early autumn. And the good news is that it’s not as destructive as some of the other bad guys on this list.

  • Appearance
    Red or orange grass blades that leave a rusty residue on your clothes.
  • Cause
    Various fungi (commonly Uromyces or Puccinia kinds)
  • Treatment
    Prevention with proper lawn maintenance.

Appearance

Rust disease will make your grass blades appear red or orange in colour, which probably isn’t much of a surprise. If you look at the affected leaves closely in late autumn, you might notice that a black, powdery substance has appeared – this means the fungus is preparing for winter.

The powder covering the blades is, in fact, spores. A foolproof way to identify this lawn disease is to look at your clothing – after coming into contact with the affected grass, your shoes, clothes, or anything that has touched it will have a red or orange tint to it, as the spores will have transferred.

Cause

There are several different species of fungus that can cause rust disease to appear. Luckily, these can only affect actively living grass blades and can’t live in the soil. This means it can cause the leaves to turn yellow and stop growing, but it won’t kill the entire lawn as it doesn’t affect the roots.

The perfect conditions for rust disease are humid, warm weather and the distinct lack of fertilisers in the lawn.

Treatment

Sadly, you won’t find any approved fungicides to use to combat rust disease. But why would you want to use fungicides if you can just prevent the infection in the first place? All you need to do is take good care of your lawn.

  • Fertilise properly.
    Not too little, but not too much – overly-fed lawns can be more susceptible to some diseases.
  • Mow regularly.
    Mowing often can help you get rid of the affected blades. Throw away the clippings afterwards, as they’re infected and aren’t suitable for composting or other uses.
  • Water smart.
    Improve the soil’s drainage when you can, and don’t saturate the ground too much.

Powdery mildew

A common occurrence when trying to grow turf against the odds, this disease can quickly turn your lawn into a nightmare. Nevertheless, it’s one of the easier ones to avoid – you just need to know what you’re working with.

  • Appearance
    A white, powdery substance covering the grass blades.
  • Cause
    Fungus.
  • Treatment
    Prevention with proper lawn care, sowing grass in suitable locations, or fungicides.

Appearance

When this lawn disease appears, you’ll notice small spots of a white, powdery substance covering the grass blades in affected areas. Over time, powdery mildew can spread, turning into larger white patches.

You’ll likely find powdery mildew more often on longer grass and in dry or shady spots.

Cause

This lawn disease, like most others on this list, is caused by a fungus. However, this one likes targeting grass growing in places where it shouldn’t.

Along with improper maintenance, overly shady areas are another aspect that can result in powdery mildew taking over. Grass needs the right conditions to grow healthy, after all, and most infections find weak turf to be a great target.

Treatment

If the disease has already spread too much, you can use a fungicide to keep it at bay temporarily. However, this really is just a short-term solution – powdery mildew will come right back if the growing conditions remain the same.

The best course of action is providing your lawn with good conditions and proper maintenance.

  • Fertilise properly.
    Apply less nitrogen fertiliser to shaded spots, as the grass in those areas won’t need as much.
  • Let more sunshine in.
    Trimming back trees and shrubs surrounding the area will reduce shade and improve air circulation.
  • Mow properly.
    Leave the grass in shady areas a little longer than the rest and remove the grass clippings afterwards.
  • Water well.
    Water less frequently, but saturate the soil well. Also, water early in the morning to give the lawn a chance to dry out by nighttime.

Red thread

This type of lawn disease is relatively common in the UK, but luckily, it’s rarely fatal, as it doesn’t affect the roots. It mostly appears in spring or summer, but a milder winter might not make it go away, either.

  • Appearance
    Patches of bleached turf with pink, cotton-like fluff.
  • Cause
    Fungus (Laetisaria fuciformis).
  • Treatment
    Prevention with proper lawn care, or fertiliser.
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Appearance

Red thread appears in your lawn as patches of lighter turf. Its most notable characteristic is that, apart from the bleached grass, you can see spots of pink, cotton-like fluff on the blades, hence the name – red thread.

Cause

This lawn disease is caused by a fungus that lives in the soil and waits out favourable conditions before attacking. For red thread, this means humid weather and temperatures from 15 to 25°C. So, it should come as no surprise if you see it in late spring or summer.

While some grasses are more resistant to red thread, and proper lawn maintenance should help protect you from it, it’s not always enough – this disease has been seen in healthy lawns, too.

In any case, if your turf is overwatered, still young, or stressed in any way, you can consider it more prone to red thread.

Treatment

Put down the chemicals – using fungicides to treat red thread disease is not recommended in domestic properties, and it’s also not necessary in most cases. Usually, you can fight the infection with just fertilisers, but it might take several years to eliminate it completely. Still, healthy roots will help the grass recover from this disease.

Still, if you try your best but don’t see any improvement, you can consult a professional. They’ll know whether you need to use fungicides or if you’re simply missing an important lawn care step.

Snow mould

You might have already guessed by its name, but snow mould appears when the weather is too cold and the grass is not growing. But there can be several culprits behind this type of lawn disease. Here, we’ll talk about the two most common versions – Grey snow mould and Fusarium pink patch.

  • Appearance
    Patches of tan leaves with grey or pink mycelia, depending on the type of snow mould.
  • Cause
    Fungus (Typhula incarnata or Microdochium/Fusarium nivale).
  • Treatment
    Prevention with proper lawn care, or fungicides.

Appearance

While they do look similar, different kinds of snow mould have different characteristics.

Grey snow mould appears as patches of light tan turf, covered in grey mycelium. This fluffy covering can usually be seen in the morning when the grass is wet and dewy. With this particular lawn disease, you can also see sclerotia forming – these are small, seed-like particles that the fungus forms to protect itself from the elements. They usually form after a few months of consistently cold weather, though, and they might not always appear.

Fusarium pink patch looks similar, but with two key differences – the mycelium is red or pink in colour, and this fungus doesn’t form sclerotia.

Cause

With both of these snow mould types, the cause is a fungus that naturally appears in the soil. However, in order to infect your turf, it needs cold, wet weather.

With grey snow mould, the fungus takes a while to develop. The disease can start in autumn, but you might only start seeing its effects well into winter.

On the other hand, Fusarium pink patch doesn’t waste time – it only needs about a month of cold weather to start wreaking havoc on your lawn.

Treatment

The best thing you can do is to try and prevent this lawn disease from taking hold in the first place.

  • Mow properly.
    Mow the grass at the right height and make sure it doesn’t get too long by the time it stops growing.
  • Fertilise at the right times.
    Avoid fertilising the lawn for a little while before it stops growing in autumn.
  • Don’t walk on frozen grass.
    Keep off the turf while it’s frozen, as damaged grass is more susceptible to snow mould.

If your lawn has been infected with this disease, encourage it to grow – it normally only attacks the grass blades and not the roots, and this will help it beat the fungus. Usually, snow mould disappears in the spring and your turf will likely recover.

However, this doesn’t mean it won’t reappear when the chilly weather returns. So, you might want to consider chemical intervention.

Treating snow mould with fungicides can be tricky, though. Several things need to be considered – the time of application, the exact type of fungus, etc. So, we recommend that you turn to experienced professionals.

Leaf blight

Leaf blight is another type of lawn disease that’s normally not fatal, but if left unattended, it can cause severe damage to your turf. It doesn’t discriminate, either – with the right conditions, leaf blight can target any lawn.

  • Appearance
    Small spots on the grass blades – yellow, tan, or black in colour.
  • Cause
    Various fungi.
  • Treatment
    Prevention with proper lawn maintenance, or fungicides.

Appearance

This lawn disease appears as small, yellow spots on the leaves. Over time, they can turn tan or even black, and you can sometimes find a red border around them. Longer grass blades suffering from leaf blight are usually more noticeable.

Cause

There are a variety of fungi that may cause leaf blight in your lawn. Still, most of the time, they develop and are treated in a similar way. The fungus only attacks the leaves and produces spores that can spread the disease in the turf.

Leaf blight can appear during longer periods of cooler, more humid weather. Underfed lawns are especially at risk, as the lack of proper nutrients can let the disease increase in severity until it kills the grass. These cases are rare, though, and usually, once leaf blight stops developing, the lawn springs back to life.

Treatment

Some grass types are more resistant to certain diseases, including leaf blight, but that’s still not a 100% guaranteed fix. However, with good lawn care practices, you should be able to prevent leaf blight completely.

  • Mow regularly.
    If you let your grass grow too long, it will trap more moisture, encouraging leaf blight.
  • Water well.
    Water in the morning to let the lawn dry out before the evening chill sets in.
  • Fertilise properly.
    Don’t over or underfertilise, as this can make diseases more destructive.

If you’ve tried everything but still can’t seem to control leaf blight, then you can turn to a fungicide. Before you do this, though, it’s best to consult a lawn care expert, so they can recommend the right course of action.

Fairy rings

A fairy ring sounds like something out of a bedtime story, doesn’t it? Well, to your turf, it might seem more like the fairytales of old. You know, the ones that would traumatise your kids instead of lulling them into a gentle sleep.

  • Appearance
    Rings or arcs of dark, discoloured, or dead grass. Mushrooms may or may not appear.
  • Cause
    Various fungi.
  • Treatment
    Prevention with proper lawn maintenance, fungicides, or soil replacement.

Appearance

Fairy rings develop in your turf as just that – rings. However, there are specific differences with each type of fungus that causes the disease.

With the most common kind, the ring of grass may appear a darker green. Some types can turn the grass blades yellow, some can stunt the turf’s growth and cause it to turn a reddish-brown, and others can just dry out and kill the grass. In some cases, if you cut across the fairy ring, you’ll notice white mycelium within the thatch layer.

If several fairy rings grow in the same lawn and meet, they won’t merge together. Instead, one ring will stop where the other starts, forming an arc. Arcs can be from 7.5 to 20cm wide, and full rings can grow up to 1m in diameter.

Sometimes, you might see mushrooms growing in a ring on your lawn. This is what many people think of as a “classic” fairy ring, due to the stories in mythology.

Cause

There are many, many different species of fungus that can cause fairy rings to develop. It’s not fully understood what causes them, but fairy rings often appear in moist lawns with a thicker layer of thatch.

While these fungi don’t usually attack the grass, they can cause a fair bit of trouble to it. When the fungus settles in the thatch, it will dry out, making it fairly resistant to watering. This can result in the turf lacking in moisture. And we all know how that turns out after a while.

Treatment

High-quality grass and proper soil preparation can reduce the risk of fairy rings appearing. However, if they do end up in your lawn, you can give it some more tender loving care to reduce their severity.

  • Aerate.
    Aerating the lawn will help water make its way through to the roots.
  • Fertilise.
    Proper use of fertiliser can help reduce or prevent the fairy ring.
  • Topdress.
    Occasional topdressing can prevent a fairy ring from developing.

If this lawn disease proves too tough, you might end up considering a fungicide. If you do get to that point, you should talk to a lawn maintenance specialist. Some fungicides can be used to treat fairy rings, but the results aren’t guaranteed and are often inconsistent. Another option is to have the soil sterilised.

If you don’t want to use chemicals or sterilise the soil, you can replace the soil (technically). This process, however, is cumbersome, complicated, and not recommended.

Need a hand with lawn maintenance?

If you require expert lawn care, look no further! Fantastic Services can tend to all your gardening needs and make sure your turf is properly maintained, lush, and thriving. Mowing, watering, weeding, you name it! So, save yourself the time and effort – turn to a lawn care specialist today!

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Takeaways

  • Most of the common lawn diseases in the UK are caused by various species of fungi.
  • Some grass varieties are more resistant to certain diseases than others, and some types of fungi only attack specific grasses.
  • Most infections can be prevented or treated with proper lawn maintenance.
  • For more stubborn diseases, a fungicide can be applied. However, that’s not the case for all types, so consult a professional before resorting to chemicals.

If you’re left with bare spots in your lawn, take a look at this post next to find out how to fix patchy grass!

***

We hope you found this article helpful and informative. If you have any other questions about common lawn diseases, don’t hesitate to share them in the comments!

Image source: Shutterstock / SingjaiStocker

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