Epichloe festucae galls the stems of Festuca species, Koeleria species and Schedonorus species. The gall often has a rather tubular appearance. It is white in the early stages, yellowing when mature.

Other Epichloe species - the identification of the host grass is important in determining likely species.

host

Photograph of the area affected by 'choke' and an image of the host grass.  Please state the host grass species in the comments section.