This wet summer has given us lush growth; it has also given ideal climatic conditions for the invasion of Red Thread, Laetisaria fuciformis, a fungal disease of turf that is more prevalent in wet summers.
At an early stage of development the leaf blade of the grass turns red, patches of grass will then brown off.
There is an increased risk of infection on lawns of low vigour where a nitrogen shortage is evident. For a quick fix an application of Sulphate of Ammonia is one solution to the problem. However we are rather late in the season to go down this path. Applications of excessive nitrogen are never to be recommended and at this stage in the growing season may encourage soft growth which is poor practice for the lead into autumn where a denser sward is ideal.
Scarify and consider drainage of surface water as more permanent solutions. However even with no treatment the grass will recover and lawns will grow together as our summer dries out. Grass cuttings and debris from scarifying must be composted correctly or the fungal spores may remain viable for another cycle of infection.