Anthracnose Basal Rot Disease
This fungal disease is presently found only on Poa annua in the UK and Ireland. It has been found on other grasses across Europe and is now being seen on creeping bentgrass in the USA.
It is caused by the fungus Colletotrichum graminicola.
The fungus that causes this disease is favoured by periods of cool, wet weather. The disease is generally considered to be an indicator of low fertility and compacted rootzone conditions.
Initial symptoms are a yellowing of individual plants in the sward. This yellowing changes with time to an orange or red colour and plants can be easily pulled from the turf as their crown tissues are completely colonised and rotted by the presence of the fungus.
C. graminicola may also cause what is called a 'foliar blight' infection which can develop on any turfgrass sward during warn, humid conditions. The turf takes on a dull, slightly darkened appearance, usually as a general effect across the entire turf area. The discoloration is due to the presence on the leaf surface of countless numbers of dark brown fungal fruiting structures. The foliar blight undoubtedly decreases the visual quality of the sward but is unlikely to kill the plants. The spores that are released during this foliar infection may lead to increased basal rot infections during suitable conditions.