Red Thread (Laetisaria fuciformis) This can occur anytime of the year, in shady, poorly aerated, compacted soils and a lack of Nitrogen. Particularly summer and autumn under warm moist conditions. The main symptoms are irregular patches of light brown or bleached leaves covered with distinctive red threads.
Fairy Rings (Basidiomycetes) Fungi primarily colonise thatch at the turf base and/or organic matter within the soil, usually caused by an infrequent watering and fertilizing regime. The rings of stimulated grass growth are the result of Nitrogen released in the soil by the Fairy Ring’s activity underground, breaking down organic matter to release ammonia, which is then processed by soil micro-organisms into Nitrates. There are three Types of Fairy Ring. Type 1 Fairy Rings (the Marasmius oreades fungus) typically appear as a ring of dead or stressed turf, bordered on both inner and outer edges by a band of stimulated grass growth.
This occurs mid-spring to early autumn when an extended period of leaf wetness will encourage the disease. Warm day temperatures and cool nights add to susceptibility. Most likely when Nitrogen fertility is low and growth is poor. Varieties of red fescues, particularly slender creeping red fescue are the most susceptible grass species. Also those fescues found in sea-washed turf. The main symptoms are numerous small (no more than 50mm) bleached spots which may coalesce to form larger, irregular patches.
Thatch Fungus (Basidiomycete) All turfed areas are susceptible to excessive thatch and it can occur throughout the year, but is most rapid from October to December. Excessive thatching can be induced by heavy liming. Circular patches up to 500mm in diameter can form where the surface of the green sinks due to decomposition of the thatch layer. Sometimes turf in the affected areas undergoes a colour change to a darker green or yellow.
New rings can appear just as green ‘patches’. It is prevalent in hot, dry conditions and may cause turf death by soil water repellency and/or toxic substances. Type 2 Fairy Rings (Agaricus spp. and Lycoperdon spp.) of stimulated grass growth are seen normally without fruiting bodies. It is rare that excessive damage is caused to the turf. Type 3 Fairy Rings (Hygrophorus spp. and Psilocybe spp.) have no distinct affect on turfgrass except when the fruiting bodies are present (normally during the autumn) when they form rings of mushrooms or puffballs. These obviously affect the quality of the sports surface. Heritage Maxx is approved for use on Type 2 Fairy Ring.
Type 1
Type 2
Type 3
Fungicides
Dollar Spot (Sclerotinia homoeocarpa)
Pink patch lacks the characteristic ‘Red Threads’. Instead leaves may become coated with pink mycelial growth. Whilst red thread may occur alone, it often occurs as a disease complex with pink patch. Severe outbreaks may kill the grass but generally affected turf will recover adequately.
Infected leaves appear water-soaked at first, then bleached. Leaf lesions have a characteristically bleached white centre with a reddish-brown border. White ‘cotton wool’ mycelium may be noted in early morning. Recovery is usually rapid, as roots are not affected. Maintaining adequate fertility is often the easiest method of preventing attacks of Dollar Spot. Fungicides such as Banner Maxx will give good control of Dollar Spot.
The affected thatch may also change colour, to orange, whitish or black. White mycelium may also be visible in thatch. Physical causes of thatching may be alleviated by additional aeration on the areas worst affected. Commercial wetting agents, e.g. H2Pro and Qualibra, specifically designed for use on turf are available from Everris. Wetting agent applications should begin at the start of the growing season.
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