Anthracnose (Collectotrichum Graninicola)
What Is It?
Anthracnose is a disease that occurs as a foliar blight, a rot of the crown, stem base and roots. The foliar blight is most common in summer, whereas the basal rot which is most common in the UK will be seen mainly in Spring and Autumn.
Have I Got It?
Anthracnose first appears as irregular yellow or bronze patches of diseased turf. The older outer leaves are affected first of all, with the younger inner leaves becoming affected as the disease progresses.
Sometimes the use of a magnifying glass will reveal the fungal fruiting structures. These have the appearance of a black pincushion and are the source of spore production.
The basal rot symptoms can vary depending on the type of grass in the sward. Annual meadow grass displays a bright yellowing of the turf in irregular shapes. When bent grass is affected the visual effect is red or bronze basal rot. The bottom of the stem will be black or dark brown. If the disease progresses the dark colour will creep up the stem of the grass.
If I Have Got It How Do I Try To Control It?
Once the symptoms are visible control rather than cure is probably the best that can be hoped for. If the turf involved has a history of susceptibility to anthracnose a preventative application of fungicide is well worth consideration. Two appropriate products are Mascot Fusion and Mascot Eland , in both cases use in August and September gives the best results.
Most greenkeepers consider cultural control to be most important; once again aeration of the turf is crucial. One of the main causes is the surface of the turf remaining wet for long periods. In view of this any mechanical slitting or spiking allowing water to percolate freely will be helpful.
The fertilizer regime is also important – do not allow the turf to become stressed by lack of nutrition.
How Do I Try To Prevent Re-Occurrence?
Ensure there is no compaction in the turf or the rootzone. This will seriously impede percolation of water and increase likelihood of this disease.
Ensure fertilizer is applied evenly and regularly enough to prevent the turf becoming impoverished. The symptoms usually manifest themselves two or three months after the stress period. In areas prone to anthracnose, hollow core and brush into the holes a mixture of Profile and Sand.