This is a disease that is caused by the fungus Laetisariafuciformis. It is usually seen during the summer and autumn months but may persist into winter if conditions remain mild.
Red thread appears as patches of damaged grass which often have a red/pink appearance. Red “needles” are present which is an excellent way to identify the disease. The size of the patches can vary from 20mm up to 350mm in diameter and the damage is fairly superficial as the leaves die back from their tips. However, if grass growth is poor and the attack is serious, the damage can be unsightly.
Fescues and ryegrass tend to be more susceptible but all turfgrasses can be attacked under the right environmental conditions. Red thread is favoured by mild temperatures and damp conditions especially after long periods of rain. It is also associated with turf that is growing under low fertility especially nitrogen. However, if the environmental conditions favour the disease, it can still occur.