Geograph - photograph every grid square

The lengths of yellow on four of the stems are a fungus [Epichloe typhina], an ascomycete, causing choke disease of grasses - see NT1512 : Choke disease of grass for more detail. A fifth, white, one to the left is an immature stage. The lowest one was being grazed on by the larva of a fly, possibly Botanophila phrenione [Anthomyiidae], which is known to be associated with choke fungus stromata. It is part of a three-some, the other two being the grass and the fungus, which together form a mutualistic relationship. The affected stems are 'choked' and do not produce flowers. This host here was Agrostis, a Bent-Grass, in the Carrifran Glen.