does not promote healthy turf. Slow draining heavy soils do not allow air to reach the soil organisms that break down organic matter to become available nutrients for plant uptake. Organic matter acts as the
Fairy Rings
FAIRY rings are troublesome problems that can develop on all amenity areas but which may or may not be regarded as a true disease problem. There are a large number of basidiomycete fungi that can initiate occurrence of these rings and they can be classified in different ways. Most frequently, we refer
to fairy rings as Type 1, 2, 3 or superficial (thatch fungi) where Type 1 is arguably the most damaging, having rings of dying turf bordered on either side by stimulated turf growth. In Type 2 rings, the symptoms are of stimulated grass rings and in Type 3, there is little if any effect on the growth of the turf but the fruiting bodies or mushrooms of the causal fungi appear in circles, arcs or ribbons across the turf. In Type 1 and Type 2 rings, fruiting bodies may develop at certain time of the year and it is only through identification of these fruiting structures that the fungus can be accurately identified. Types 1 to 3 fairy rings are formed as a result of the growth of the fungus through the rootzone, with a relative general decrease in the quantity of mycelium that exists in the affected area. With superficial fairy rings, the fungal mycelium is found at the base of the sward or in the thatch and in all cases, where these fungi are active, their presence can be confirmed by their characteristic musty smell. Some researchers have alternatively categorised these basidiomycete fungi in to two groups; Edaphic, where the fungi colonise the soil and Lectophilic, where the fungi colonise the thatch. Regardless of their classification, the symptoms produced by these fungi can cause significant management problems in amenity situations.
All fairy rings causing fungi break down the organic matter in the thatch or rootzone, making nutrients available for uptake either by themselves or by the turfgrasses in the colonised area. These fungi also impart water- repellence to the affected rootzone that will be more apparent in areas with Type 1 ring activity and also in rootzones with a higher sand content. With regard to managing
these problems, reducing their food source (the thatch or organic matter) will reduce the activity of the fungi or the severity of the symptoms that are produced. Using appropriate wetting agents on heavily affected areas will allow the turf to continue to take up water and nutrient and therefore minimise the stress to the turf during the summer months. Symptoms of some fairy ring development can be masked by careful
application of nutrient and the fruiting bodies can be mown or raked away from the infected areas.
There are fungicides that
have approval for use against the fairy ring causing fungi but their efficacy will be influenced by application timing and the condition of the rootzone at the time of application. If they are to be used, it is advisable to apply them following a wetting agent application to ensure that the product reaches the target. In Type 1 rings, the fungal mycelium may be over 0.5m deep and
management of these rings by fungicide use alone, may be difficult. Always ensure that the disease is correctly identified prior to the application of any plant protection product.
Dr. Kate Entwistle The Turf Disease Centre Tel: 01256 880246
cementing agent that causes fine particles to bind together into aggregates. Therefore, in physical terms, the OM content is significant because it is difficult to maintain good soil structure in soils low or devoid of organic matter. Correctly ascertaining a soil’s pH is a necessary requirement due to the fact that, at higher pH levels, certain nutrients react with other compounds present in the soil and become unavailable for uptake by plants. Adjustment of the soil pH will result in the release of these nutrients back into soil solution. This adjustment is not necessary if the soil used has a sufficiently low pH value. It is also the case that fine turf cultivars such as those found on golf greens require slightly acidic conditions. This is, in part, because of the wild grass species that the turf cultivars are derived from, were evolved to grow in upland, acidic conditions, It is also the case that the level of microbial activity in the soil, is also pH dependent. So be aware, ask questions of your supplier. It is simply not enough to rely on the paperwork, it is a good idea to visit your intended supplier’s works, inspect the production facility, find out if their other customers are happy with the supplied product, and where the soil comes from originally? Inspect it yourself - are there roots present? Does it contain Bracken (Pteridium aquilinum), Mares-tail (Equisetum arvense) or worse still - Japanese knotweed (Polygonium japonicum)? At the very least, request that a sample be sent to you. If a recent specification sheet is unavailable, then you should ask why. Find out what soil associations the supplier belongs to.
Substandard and unsuitable material is being sold to the unwary as premium grade topsoil - make sure your job doesn’t receive it. The origin of doubtful quality soil is obviously unreported by unscrupulous suppliers, therefore these checks are essential. The standard that the laboratory
contaminant results are compared against is DEFRA’s Contaminated Land Exposure Assessment Soil Guideline Values intervention levels (CLEA SGV’s). If the concentration of a contaminant rises above the prescribed value, then that substance is deemed to be present at unacceptably high concentration for the soil’s intended purpose. The SGV will vary according to the use that the soil will be put to. These categories are -
Residential, Allotments and commercial/industrial - the sports turf industry falling into the last category.
Because of the increasing supply of material described as ‘topsoil’ the British Topsoil Suppliers Association was set up. It ensures that its members only supply true, genuine topsoil. It will not have been obtained from a dubious source, thus the product supplied is able to be classified as ‘true topsoil’. The members achieve this by regular quality control monitoring and being aware of the soil’s original source. It is also worth mentioning that having a current specification sheet increases confidence of both the intermediary and the final user, for the material supplied.
Having this information available to the end user, in the form of a current full specification sheet, is becoming significant as more soil of unspecified provenance appears on the market. For copies of SGVs and other technical material referred to here see: - www.environment-
agency.gov.uk/subjects/landquality/1 13813/672771/
Nigel Fahey B.Sc. is the laboratory manager for Baileys of Norfolk, a founder member of the BTSA & BRTMA.
disease OF THE MONTH
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