Damage rating


Type of disease


Red thread - Laetisaria funciformis

How to recognise it

Irregular, reddish patches of dying grass appear in the lawn up to 45cm in diameter in late summer. Pinkish strands of fungal mycelium can be seen among the grass leaves, with red-pink, needle shaped growths coming out of the strands.

Why it’s a problem

It rots the leaves and stems of the grass (although the root is usually unaffected), leading to the top growth dying back.

Where you are likely to find it

On lawns, particularly on light or poor soils or after prolonged periods of heavy rain (which washes the nitrogen out of the soil).

Many types of turf grass are affected, although red fescue is most susceptible.

How to prevent it

Ensure good drainage (eg through scarification and aeration) and an appropriate feeding regime (including nitrogen). However, don’t overfeed with nitrogen in the autumn which can make the grass susceptible to other problems such as snow mould.

Applying the fungicide trifoxystrobin can protect against infection.

How to get rid of it

Improve soil fertility with a feed including nitrogen, which will normally encourage fresh growth and allow the bare patches to recover. Grass seed or re-turfing can be used for any patches which do not recover.

Is it good for anything?!

The onset of fungal diseases in a lawn is a good indicator that the grass is not as healthy as it can be and needs some TLC to prevent more dangerous diseases or weeds taking a hold of your lawn.

Other useful information

The pinkish strands are the mycelium (the thread like structure most fungi consist of) and the needle-like structures growing from them are stromata. The stromata survive in the soil for up to 2 years before germinating and infecting the grass plant through the leaf stomata.