Red thread
A lawn fungus that leaves pinkish-red, needle-like threads on grass blades and tan or bleached patches, especially in cool, damp weather.
Also known as: Pink patch, Laetisaria
Symptoms and identification
Irregular tan or pinkish patches 5 to 50 cm across appear in the lawn. Fine, pink to red, thread-like growths stick out from the tips of grass blades, and in wet weather a pink cottony growth may be seen.
Causes
It occurs in cool, damp weather, mainly in spring and autumn, on lawns that are low in nitrogen, slow-growing or poorly drained. It rarely kills the grass.
Organic treatment
Feed with a slow-release nitrogen fertiliser and the lawn grows out of it, usually within a few weeks. Collect clippings from affected areas.
Prevention
Feed the lawn with a nitrogen fertiliser at the right time of year, aerate and improve drainage, and avoid long periods of leaf wetness. Choose resistant grass seed when sowing.
Chemical treatment (use with care)
Fungicides are seldom needed because the damage is mostly cosmetic and corrects itself with feeding.