It is recognised by the die-back of quite large areas of grass on compacted lawns in particular. Usually found in Autumn, but also in spring after there has been snow lying on the lawn for some lengthy period. It can spread and take hold under cover of snow - hence its common name of Snow Mould.
Many other lawn browning problems are wrongly diagnosed as being Fusarium - and wrongly treated as a result.
Fusarium Patch disease starts as a small yellowing patch which turn brown as the patches enlarge. Sometimes - in damp weather - a white or pinkish mould can be seen in the patches. It normally subsides a little as the air temperature warms up and lawns dry out a little. The colouring also gives Fusarium is more common name in the USA of Pink Snow Mold.
As with all diseases, it is much easier to prevent than to cure. Again it is proper lawn care and maintenance which is the answer. Fusarium patch disease is more likely to spread when there is snow cover. It can also be present without the snow, but is one of the few turf diseases which is happy with snow for its furtherance. Snow is a desirable but not necessary ingredient to allow the mycelium to spread.
Whilst Fusarium Patch disease can show up upon domestic lawns, it is the dread of golf course managers, for its appearance on the greens - as often happens - can eventually lead to a poor quality green to play on, and is visually unacceptable to most golfers!
Fusarium attacks all popular varieties of turf grass that are in general use. Its prevalence on fine sports turf has given the mistaken analysis that it is only a disease of fine grasses - Wrong! It is the actual management of the turf area which is generally the deciding factor. Spiking, feeding well in the spring and summer and avoid over use (compaction) of lawns - particularly on heavy ground - in damp conditions. Continual watering - without adequate drying and drainage, will hasten the disease. It does not like dry lawns.
Treat at first signs. If treated soon, then it will rarely become more than an irritation -rather than a disaster.