Dollar spot
A lawn fungus that produces small, round, straw-coloured spots about the size of a coin, which merge into larger irregular patches.
Also known as: Lawn dollar spot
Symptoms and identification
Sunken spots 2 to 5 cm across bleach to a straw colour and merge into larger patches. On blades, tan lesions with a reddish-brown border girdle the leaf. In the early morning dew, fine white cobweb-like threads cover affected grass.
Causes
The fungus is most active in warm days and cool, humid nights with long periods of dew. Low nitrogen, dry soil, thatch buildup and drought stress make lawns far more likely to be hit.
Organic treatment
Feed the lawn with a slow-release organic fertiliser and water deeply, as a healthy lawn usually recovers within a few weeks. Remove clippings from affected areas.
Prevention
Feed lawns regularly with nitrogen, water deeply and infrequently in the early morning, and keep thatch under control. Mow at the right height with a sharp blade and brush off dew in the morning.
Chemical treatment (use with care)
A fungicide labelled for dollar spot can be used on valuable turf, following the label, but correcting feeding and watering is usually enough.