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The ring of bare soil which is often seen between a band of darker green grass which has been attributed to a variety of causes worldwide. In Germany the bare rings were produced by witches performing a ritual dance on Walpurgis night, whilst in the Tyrol a winged dragon passing over a field at the epoch of Pegasids and Martinmas branded the grass with it's fiery tail. The Dutch meanwhile recognised the marks of evil in these rings, attributing them to places where the devil, in resting his churn, burned the turf. Blemishes which are casued by the Lord of Darkness would not recover as quickly as those produced by natural fire and hence they were observed to take up to seven years to depart.
Scientists as early as the sixteenth century put forward the hypothesis that fairy rings were caused by lightening. Some exponents of the lightening theory go to great lengths to explain how the geometrical considerations of electromagnetic physics, relating to an electrical discharge of this type, cause the turf to be burned more on the perimeter than the centre. Others took pains to explain how the variations in the size of the ring arise.
Bradley in 1789 describes two causes of the fairy ring phenomenom. The bare earth was a path made by burrowing ants which 'flung up soil extremely fine' resulting in the improved vigour in the immediate vicinity. He goes on to describe the ring of slime left by slugs and garden snails which go over the same ground at least twenty times in circular courtship. When this slime is putrefied it gave rise to the ring of toadstools.
The zone of stimulated grass growth that we often see in some fairy rings is the subject of yet more postulation. Before the introduction of inorganic fertilisers one of the methods which a gardener or farmer would employ to improve the fertility of the soil was to apply an appropriate manure. It is therefore not suprising in the writings of this era to find reference to various animals as the cause of this luxuriant growth. Such animals as fallow deer, moles, rabbits, cows and goats were observed to adopt circular patterns of behaviour during courtship or play. The deposition of dung and urine during the course of these events was presumed even and consistent enough to produce the observed effect.
Superstitions relating to luck vary from different sources and are often contradictory. For example, to step inside a fairy ring can bring good or bad luck depending on your source of information. To have fairy rings in a field near your house was said to bring good fortune but where two rings joined together brought bad luck to the area. The dew from the darker grass of the fairy ring was much prized as a cosmetic skin treatment for a maiden's complexion. It is also used as an ingredient for a love potion.
A gentleman by the name of William Withering (1792) was the first to recognise the true cause of fairy rings to be fungal in origin and so once his ideas where accepted, the romantic age of fairies dancing in moonlit shadows began to fade into the mists of children's bedtime stories. He described one particular fungus Agaricus oreades.
Today we have identified a great many different species that give rise to fairy rings. The rings themselves are found to occur in the distinct types according to the effects that they have on the turf.
Type One Fairy Ring
The first type of ring has a circle of dead or dying grass inside a larger band of darker grass. In the UK type one fairy rings are mainly caused by Marasmius oreades. The toadstools or 'caps' of M.oreades are mostly produced within the dead grass area and are a reddish tan to buff in colour depending on the soil conditions and other enviromental factors. Unlike many other fungi, caps og M.oreandes can withstand long periods of desiccation and, providing they are not disturbed, will re-hydrate when moist weather returns and continue their life cycle.
Type 1 fairy ring diagram:
The ring of dead or dying grass results from the production of a toxin by the fungal mycelium in the rootzone of the turf. The poisoning effect of this toxin is compounded by water stress caused by the presence of the ring of waxy mycelium that can be found just below the soil in the dead area. This thick layer of mycelium presents an impervious barrier that prevents the grass from getting sufficent water. The fungus lives off organic matter which it breaks down for food but in doing so releases nitrogen into the surrounding soil in the form of nitrates and ammonia. This has the effect of producing stimulated grass growth in the area adjacent to the fungus.
The subterranean mycelium advances away from the centre of the ring by six to eighteen inches or more each year. By studying aerial photographs it is possible to estimate the age of fairy rings. In Colarado, rings where reckoned to be 250 - 400 years old and one in Belfort (France) was found to be about 700 years old, being one quarter of a mile in diameter.
Type Two Fairy Ring
The second type of fairy ring produces a ring of stimulated grass growth in which toadstools or puffballs can be found at certain times of the year. Although this is not as damaging as the type one fairy ring since it does not kill the grass, it is still a disfiguring scar on an area of close mown turf such as golf or bowling greens. The dark bands or ribbons as they are sometimes known are more evident in long hot dry summers when then surrounding grass tends to lack colour.
Type Three Fairy Ring
The third type of fairy ring has only a circle of toadstools or puffballs, without having a stimulated or dead area. Also included in this category are the ring forming fungi that are found in woodlands. Type three fairy rings are easy to live with as the symptoms can be removed by mowing.
Eridication
Type one and two fairy rings are not easy to control because of their position within the soil and the fact that they can be found as deep as 30cm below the soil surface.
Many attempts have been made to eradicate fairy rings and Greenkeepers often have their own particular remedy. In the past the practice of manuring the bare areas of rings has been tried as it was thought that they were the result of some nutritional deficiency. Many chemical methods have been tried with varying degrees of success including fungicides based on Cadmium and Mercury. Soil treatment with methyl bromide gas and formaldehyde has also been tried. In the early 1980's Oxybarboxin was launched as the product 'Ringmaster' and proved useful in controlling type 1 rings but the type two ring usually needed several applications to completely remove them. 'Ringmaster' was followed by 'Fairy Ring Destroyer' containing the fungicide triforine and by 'Mascot Clearing' a formulation of benodanil. Today all these products have been withdrawn from sale and the only recommendation for fairy ring control with a fungicide is on the 'Heritage' label, however at present this is backed by limited trials data on type 2 rings only.
The main problem with type one fairy ring is finding a way of penetrating the waxy mycelium that forms an impervious barrier to most materials. One method of control claimed to have some level of success is to apply daily heavy irrigation to the whole area occupied by the ring. This has to be carried out for at least a month. Unfortunately , whilst drowning the fairy ring fungus, the resultant waterlogging can create other problems by washing away the soil nutrients and encouraging moss and other fungal diseases.
Some people have tried using surfactants to break up and disperse the ringds. One such product 'Clearing' is aimed at this method and contains soil penetrating surfactants suitable for use on all types of fairy ring as well as superficial fairy ring (thatch fungus).
An old method described in the Sports Turf Research Institute, in their booklet on turf diseases (circa 1975), was also reported to give successful control but, because it demanded a high input of labour, it was a very costly labour. By this method the turf in the infected area is removed and the soil below is dug over and treated with a drench of formaldehyde and a wetting agent. Great care has to be taken in to avoid scorching the surrounding healthy turf with the formaldehyde or contaminating it with infected soil. The treated area is covered for 7 - 10 days with polythene to 'sterilise' the infected soil with the formaldehyde vapours. After further digging the site must be left exposed for a period of two weeks to allow the solvent vapour to disperse before the surface levels can be re-instated and the site re-seeded or turfed. Apart form the obvious cost in labour there was also the hidden cost in sports turf areas of providing an alternative playing surface while treatment is being carried out.
Whichever way you look at it the problem will not go away - unless, of course you believe in magic!.
Article written by Graham Paul
Please contact Sherriff Amenity for specific answers to your fairy ring problems.
'Heritage' is a trademark of Syngenta Group Company
'Clearing' is a trademark of Vitax Ltd | 
