Winter Damage in Lawns

Fusarium patch/Pink snow mould
Latin name: Microdocium nivale/Fusarium nivale/Gerlachia nivalis

After a long and hard winter, many lawns look miserable. Often you see bare patches in the lawn, where the grass has withered away. Sometimes the problem extends to the entire lawn leaving it with nearly only bare patches – a typical symptom of the worst known diseases in our northern hemisphere – the pink snow mould.

Symptoms

Damage appears not only after snow, but also in humid weather at temperatures just above freezing. Patches of 4-6 cm with grey waterlogged plants are seen when the attack commences. The patches spread to form plate-size areas which coalesce. A dark brown rim is often seen along the outermost edge where the infection is active.

A grey-white to pink cottony mycelium forms over the attacked area when the humidity is high enough. This resembles a paper-like layer after snow.

The grass regenerates from the middle of the patch.

Hosts

Fusarium patch can attack all turf grass species, however bentgrass, annual meadow grass and perennial ryegrass are particularly susceptible.

Time

Fusarium patch is the most important fungal turf disease. The damage is seen throughout autumn and winter and upon snow melting, if any, in March. Heavy rainfall can dislodge spores and infections can follow run-off patterns.

Weeds

A great deal of weed seeds can be found in nearly all types of soil. Bare patches in the fields will allow weed seeds to germinate, and as a result we may face serious problems in terms of weeds this year.

Repair

In many cases the grass will regenerate from the attack of Fusarium. Depending on the severity of the attack, a regeneration will take a short or long time. In case of a severe attack it is recommended to repair by overseeding i.e. introducing new seeds into the existing sward. Click here for more information.

As a rule, attacks mainly occur where snow lies for a long period e.g. in slopes or along hedges. To prevent an attack, spraying with a fungicide can be done in late autumn.

It is important not to leave a lot of clippings on the turf area before winter sets in.

At present, no turf varieties are fully resistant against Fusarium, but through great many years DLF-TRIFOLIUM has systematically trialled breeding material exposed to a constant, heavy attack of Fusarium. This has resulting in new varieties having an improved resistance.