Gray Leaf Spot 
A rare disease of turf in the UK, first identified in 2020, caused by the fungal pathogen Pyricularia grisea or Pyricularia oryzae, with synonyms of Magnaporthe grisea and Magnaporthe oryzae respectively.
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Helminthosporium spp
A genus of fungal pathogens, which are now mostly reclassified as Dreschlera spp.
Leaf Dieback
Disease infection can cause grass leaves to dieback, however, a common cause of a grass leaf dying back is due to its natural lifecycle, from being a young leaf, to maturing, aging and then senescing (aging without cellular division), which results in dieback, progressing from the leaf tip towards the base of the leaf (basipetally). (Aldous, D.E. & Wilson, J.R. ‘Turfgrass growth and physiology', p55, in Aldous, D.E. (Ed) (1999), International Turf Management Handbook).
Leaf Spot
The leaf-blighting phase of Melting out disease. The symptoms are typically those of small brown spots on a leaf, but also yellow mottled streaks. It is a minor disease of smooth stalked meadow grass in particular; as well as perennial ryegrass. It is caused by numerous fungal genera, with Drechslera species being relatively common. Leaf spot can progress on to the more damaging melting out aspects of this disease complex.
Melting Out
A continued development of Leaf spot, which causes damage to the base of the surface vegetation. It affects the leaf sheath at the plant's crown (called the crown rot phase) where leaves originate from, and it can also develop to its root (called the root-rot phase). The infected parts turn a yellow brown, may be darkened and moist in appearance, along with the presence of white fungal spore deposits. A range of fungal genera cause the symptoms shown by Melting out.
Microdochium Patch
Mildew
Pink Patch
A fungal disease caused by Limonomyces roseipellis. It will typically occur with red thread, under the same conditions and host plants, with a pinkish mycelium initially growing on the margins of grass leaves but without fine needles (unlike red thread). Summer to autumn can be key times for this disease to attack, primarily when there is a lack of nitrogen for strong, but not lush, grass growth. Control methods are essentially the same as for red thread disease.
Pink Snow Mould
This is caused by Microdochium nivale (the same as for Fusarium Patch disease) and results from conditions present under snow cover of at least 10 days duration, being exposed when the snow melts, leaving dead areas with either a white or pink coloured mycelium (the pink colour especially develops after being exposed to day light), often in mats, being present on the sward surface.
Post-emergence Damping Off
Seed germination has been successful, however, seedlings which become infected, often appear in initially yellowing, then red and bronze tinged, patches, collapse and die, forming moist patches of decaying seedlings. Common fungal pathogens include Fusarium spp, Pythium spp, and Rhizoctonia spp.
Wet soil conditions, high density of seedlings through high seeding rates, poor air circulation, high relative humidity amongst the grass leaves and slow leaf development following germination all increase the chance of this damping off occurring.
To reduce the chance of this type of damping of
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