Fusarium - Snow Mould In Lawns. Advice and information.

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!

• Do NOT use feeds in late summer or autumn that have a high Nitrogen content - such are the spring and summer lawn feeds. Last feed with these should be early August at the latest, and should be a proper feed formulated for the autumn growing period. Summer feeds are too high in Nitrogen to be applied in early autumn
• Apply a heavy Potash based fertilizer in the Autumn. Liquid Tomato feed is good for this!
• Spike compacted areas often through the year. Compacted soils - from foot traffic, mowing, and other mechanical and environmental causes, are ideal conditions to assist the Snow Mold to develop. Lawn aeration is necessary for any good lawn.
• Do not allow your lawn to become a bed of thatch (dead and dying grass) for this is a very suitable place for the spores to 'nest' for the summer, in readiness for the winter and snow covering which will help its spread.
• Don't walk over the lawn when it is covered in snow. This will facilitate the spread as your foot traffic carries it about and deposits it to other areas of the lawn. This is one of the reasons why it spreads so quickly on golf greens - where there tends to be year round use.

• Originally Chemically treated with Carbendazim, Carbendazim is a fungicide and is dangerous to worms and has been banned in the UK and USA - Triadimefon is the next best remedy, and is still available in its natural form in Australia.
• The most common remedy in the EU is Triadimefon, it is low aqueous solubility and less toxic to worms and honeybees. The flip side, it is highly toxic to birds, fish and pond life. Becareful of the run off if near to a pond or part of the water table, you do not want to cure one problem by creating a bigger one.

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.

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