White Leaf of Annual Bluegrass

Phytoplasma

A few reports are coming in on "white leaf blades" on golf course turf.  The turf is primarily annual bluegrass but can occur on other grasses.  If it is what we are mentioning below, there is not much you can do but wait for it to disappear...

On some golf course fairways through central Ohio a rather odd looking disease is beginning to appear. The disease is sometimes known as white leaf of annual bluegrass. Symptoms appear as white spots on Kentucky bluegrass (Poa pratensis), annual bluegrass (Poa annua), perennial ryegrass (Lolium perenne), and to a lesser extent on creeping bentgrass (Agrostis stolonifera). The leaf symptoms appear as white or completely bleached out leaf blades caused by the degradation of chlorophyll.

Photograph 1. White leaf symptoms on a Kentucky bluegrass/perennial ryegrass turf. The white leaf blades are caused by a phytoplasma that degrades the chlorophyll.

The pathogen is a phytoplasma which is classified in a group of similar prokaryotic organisms known as mollicute. The difference between normal bacteria and mollicutes, like phytoplasma, is no cell wall is present with mollicute organisms. Phytoplasma appear to be transmitted through leafhoppers which deposit the pathogen in the plants phloem.