Independent Cambridgeshire lawn care services

Disease control

There are many diseases that can impact the visual appearance and health of your lawn. Lawn diseases typically cause discolouration and affect the overall health of the grass plant. Each disease can be caused by different problems and environmental factors.

The most common disease are:

Fairy rings

What are fairy rings?

The most damaging fairy rings are slowly spreading colonies of the fungus Marasmius oreades, which live in the roots of turf, altering the appearance of the grass and producing toadstools at certain times of the year, mainly in late summer and autumn or when conditions favour.

Other colonies of fungi cause fairy rings as well, but most have no effect on the turf, or even seem to enhance the growth.

All types of lawns and areas of rough grass can be affected by fairy rings.


Symptoms are variable, depending on the fungi responsible. Most have virtually no effect on the turf and are only noticed if toadstools appear.
You may see the following symptoms:

  • An irregular green ring of grass gradually expanding across the turf (Type 2)
  • An irregular ring of dead grass gradually expanding across the turf (Type 1) immediately adjacent to the dead grass, the grass may be greener than usual.
  • Crops of brown toadstools at certain times of the year (Type 3)


Non-chemical control

Since the toadstools produce huge volumes of airborne spores which are carried long distances, there is little point in removing toadstools from the lawn to try and reduce the risk of infection.

In principle, excavating the active ‘front’ of the colony (ie the ring) and replacing with fresh soil would remove the ring. In practice this would mean removing turf and soil to at least 30cm (1ft) depth, replacing with fresh soil and returfing or reseeding, which would be very expensive and scarcely feasible.

Where dead patches of grass occur, spiking and watering to break up the water-repellent properties of the fungal colony is helpful, as is feeding.

Chemical control

There are some fungicides with a wetting agent added available for fairy ring control, however they are not guaranteed to cure the problem. Please speak to you CTT adviser for more information.

Fusarium patch

What is Fusarium patch?

This disease is caused by the fungus Microdochium nivale (formally Fusarium nivale). It is one of the most damaging diseases of turf grasses and can be difficult to control. It is found most frequently during autumn, winter and early spring, but attacks can occur at any time of the year.

The disease is sometimes very noticeable after thaws of snow, when it is given the common name of snow mould.

Fusarium patch is particularly troublesome on annual meadow grass, but can also affect bents, fescues and perennial rye-grass.


What to look out for;

  • The disease is first noticed as small patches of yellowish, dying grass that later turn brown
  • Patches increase in size and may reach 30cm (12in) or more in diameter, often merging together so that large areas can be affected
  • During wet conditions a white or pinkish, cottony fungal growth may be noticed, particularly at the margins of the patch. This is not to be confused with another fungal disease called red thread, or with slime moulds in turf

Non-chemical control

  • Ensure that the lawn dries rapidly after dews or rainfall by improving the aeration and drainage. This can be done by a combination of scarifying, spiking and hollow- or solid tining
  • Improve general airflow over the lawn by pruning back overhanging trees or shrubs
  • Remove heavy dews in the morning with a switch (a long, pliable rod) or bamboo cane
  • Avoid high doses of nitrogen fertiliser in late summer or autumn – use a proprietary autumn lawn feed instead

Chemical control

A fungicide can be used all year round except during drought conditions or when the lawn is frozen. There is a risk of resistance occurring in the fungal population, therefore, the product should not be applied more than twice a year and is best used in conjunction with other control methods.

Red Thread

What is Red Thread?

Red Thread has become a common disease on lawns, particularly those with poor light, and soil. Red Thread can also occur after periods of heavy rain during which plant available nitrogen is washed from the soil. Red Thread can affect most grass types including annual meadow grass, fescue and bent.


The symptoms are usually seen during late summer when sporadic reddish patches of dying grass appear. It may be on closer inspection red needle like threads can be found growing on the grass leaves.

The disease enters the leaf by the stomata which become the point of infection. Red Thread is more of a leaf disease so is unlikely to kill the root system. Therefore turf can recover adequately given time.


Red Thread is a sign of low fertility, therefore a good fertiliser program and lawn heath check are good ways to avoid this disease.
CTT can take preventative and curative action to reduce the effects of Red Thread to your lawn.

Rust disease

What is lawn rust disease?

Rust is a common foliar disease of turf. It is caused by various fungi, usually Puccinia or Uromyces species. Infected areas may produce huge numbers of air-borne spores. When walking your lawn you will notice the brown from the rust spores covering your shoes.


Typical symptoms of lawn rust include;

  • Affected patches of grass turn yellow
  • Large numbers of tiny, spore-producing pustules break through the leaf surface. The colour of the pustule will depend on the species of rust and the type of spore it is producing. Most commonly the pustules are orange, but in autumn the fungus may switch to producing black pustules containing over-wintering spores
  • When walking over an affected lawn, shoes or clothes turn orange as they become coated with vast numbers of spores
  • Severely affected leaves may turn brown and shrivel, but the rust does not usually kill the grass


Non-chemical control

Feed the lawn regularly during the growing season to maintain vigour

Avoid high nitrogen fertilisers in the autumn, as the resultant lush growth may be more prone to attack by rust and other diseases such as Fusarium patch

Mow regularly to reduce the number of affected leaves, removing the clippings

Improve air circulation by selective pruning of overhanging trees and shrubs and good aeration.

Chemical Control

There are no fungicides for the control of rust on lawns. Chemical control of rust is usually unnecessary as the symptoms are temporary. Even lawns that are heavily infected in autumn will usually produce healthy growth by early summer of the following year.

A lawn care maintenance programme can help prevent lawn fungus.

  • Most fungal diseases use the moisture on the leaves of grass plants to produce and move spores. Avoid watering just before dark as water will remain on the leaf blades longer at night.
  • Mowing less frequently during humid hot weather reduces stress on the grass plants and minimises the possible transfer of grass diseases.
  • The way you mow affects your lawns ability to resist diseases. Mowing too low increases the chances of scalping. Cutting your grass extremely short is very stressful to the plant and leaves it susceptible to lawn diseases.
  • Blunt or dull mower blades shred the tops of the grass leaves, and expose tissue for lawn diseases to enter the plants easily.
  • Often, lawn diseases are specific to certain varieties of grass and one approach may be to introduce other varieties of grass into your lawn.
  • Increase light, air access and movement over the grass by pruning overhanging trees and shrubs, will all help reduce incidences of turf disease.
  • Lawn aeration also helps produce healthy grass.

Implementing the above good practices will help reduce the likelihood of a lawn disease. These techniques along with the potential use of a fungicide will help reduce incidence as part of an Integrated Disease Managment Plan. A professional fungicide may have to be applied to control the most damaging lawn diseases. These products are not available in DIY stores.

What is a turf disease?

There are a number of turf diseases that are common in the UK. The development of most diseases is usually dependent upon weather conditions, so recent weather conditions are considered during any diagnosis. Most diseases will have certain characteristics such as discolouration of the grasses, brown dry patches or signs of fungi (mushroom type growth).

CTT provides lawn disease control programmes to eliminate these diseases from your lawn when required. Some lawn diseases can be controlled with the application of the most beneficial fertiliser for your lawn, at the correct time of year. It takes a trained eye to identify the best fertilisers for your lawn, but this is something that our lawn experts will identify during your regular treatments.
The best way of avoiding these diseases is to have a regular lawn maintenance programme in place. This will keep your lawn free of diseases for the vast majority of time. We only recommend a fungicide treatment programme when normal treatments aren’t enough to stop the disease from progressing.

Speak with us

With a pedigree of specialist experience working with top golf courses and domestic lawns within Cambridgeshire and beyond, you can be assured that we will help you get the very best out of your lawn for seasons to come.
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