Unfortunately, there are several fungal diseases that affect turf, two of the common culprits are Fusarium Patch and Red Thread disease.
Fusarium Patch is most likely to leave lasting damage to your lawn. It produces notable yellow / brown patches which can have a white or pink fluffy mould around the edges and is capable of killing the grass. Fusarium will become a problem when the conditions are favourable; a rise in temperature, damp and dewy mornings and lush young growth. Unfortunately, the only guaranteed way to control this is with the application of a professional fungicide.
Red Thread disease is identifiable from thin red / pink needles shooting from the side of the leaf blade. The grass plant also can take on a pinkish tinge and you’ll be able to see a pink candyfloss like growth; this is the fruiting body of the fungus. These symptoms are usually brought on by a lack of nutrients in the soil so an application of a balance turf fertiliser should clear it in most cases. Once the disease has passed it can leave the turf looking bleached in colour and in a strong period of growth this should disappear after a couple of weeks. Thankfully Red Thread isn’t a terminal disease, more like us humans getting a heavy cold.