Photo of the week: salts or rapid blight?

This poa green was experiencing damage that appeared to be related to elevated salinity, with 3.8 dS/m saturated paste equivalent readings in the damaged areas, and much lower electrical conductivity (EC) readings in the healthy areas. However, poa can tolerate EC levels of up to 4 dS/m, so the damage is probably not due to salinity alone. It is likely that rapid blight is involved in the damage, because this disease can attack at EC values above 1.9 dS/m, as…