Microdochium (Microdochium nivale) (formally Fusarium) Patch is found in warm season and cool season grasses like wintergrass, bent grass, fescue, ryegrass, Kentucky Bluegrass and low mown Kikuyu in cooler climates. Initially round patches appear as small, water-soaked spots less than 5 cm in diameter. They then change in colour from orange brown to dark brown and finally to a light grey.
Some spots may enlarge but are usually less than 20 cm in diameter. On low-cut turf a halo-like “smoke ring” could appear on the outer area of the patch. The outer ring may have a water-soaked appearance.
In wet conditions a fluffy covering of white mycelium may be seen on matted leaves. This mycelium is white, but on exposure to sunlight induces spore production which is a pink colour.
Microdochium Patch can be caused by extended periods of time of foliar wetness over numerous consecutive days, normally in cooler temperatures. An unbalanced NPK ratio in the soil, with high Nitrogen and lower Phosphorous and Potassium, areas with slow growing conditions and heavy thatch can also be contributing factors.
We have a selection of professional lawn care products available online and can help you choose the best fungicides based on warm or cool season grass identification. Message Lawn Addicts for further advice on other products.