Red Thread (Pink Patch)

The causal agent for red thread or pink patch is Laetisaria fuciformis and Limonomyces spp. It is generally noticed as brown patches appearing in the lawn. Closer inspection particularly at the outer edges of these brown areas will reveal the characteristic red threads of mycelium growth. This is the most common disease exhibited on lawns comprised particularly of ryegrass or fine fescue, however, it can affect all other turf species.

It is primarily a function of nitrogen deficiency and can occur at any time of the year, but tends to be more common from autumn until spring when consistently moist leaf blades provide ideal conditions for its propagation. It can be very site specific particularly in areas that are well sheltered or shady. Red thread can be prevalent on new sites particularly when the original topsoil has been removed and replaced.

The base saturation fertility level on these soils is low and as a result the plants struggle to uptake sufficient nitrogen to meet their requirements. It can take some time to build this fertility back to desirable levels. Therefore, during this period of time a regular balanced fertilizer regime is recommended.