Identification of turf Disorders Andrew Wight

What is a disorder? Disorder – A disorder of turf is a non physiological threat to the health and quality of the turf i.e. it does not directly attack the turf itself by damages by indirect means e.g. Non living threat to turf Does not infect living or dead grass Does not spread from one affected area to another Physical, chemical or mechanical damage

1. Compaction. The soil has been compressed reducing air pores and drainage. This reduces plant growth and results in a thin cover with a hard playing surface. Treat by aeration (hollow tines are best.)

Dealing with compaction Aeration allows us to break up this compaction allowing water and roots to move into the soil. Improving the drainage of turf areas by the installation of drainage systems. Closing the sports area in extremely wet soil conditions Top dressing with sandy soils as sand resist compaction because it contains large rounded and angular particles that do not stick closely together (if you squeeze sand and then release it you will find it will not bound together).

Compaction Symptoms Hard surface, poor drainage, thingrass cover. Causes Foot/machinery traffic, poor drainage (wet soils compact easily.) Effects Poor root growth and drainage Thin grass sward

2. Dry patch- soil has become hydrophobic (water hating/water repellent) grass turns blue/grey colour and later browns off. Treat with wetting agents.

Dry patch Water repellent root zone which can be caused by fungal activity, thatch layers or a build up of organic residue on the soil/sand partials. Symptoms Grass changes colour (blue/green first) then browns and wilts Water runs off the affected area Cure Wetting agents can be used to help reduce problem Spiking when irrigating to aid water into the soil

3. Black layer- caused by lack of oxygen due to poor drainage 3. Black layer- caused by lack of oxygen due to poor drainage. Anaerobic bacterial produce hydrogen sulphide and this reacts with metals in the soil (iron etc.) causing the black layer. Treat with aeration and sandy top dressings, deal with any blocked drains etc. (Get air into soil)

Black layer What is it? In soils with and poor drainage and little aeration, anaerobic bacteria produce hydrogen sulphide this reacts with metals (iron) in soil to produce black deposits (layers). These layers are toxic to grass roots and so restrict root depth. Symptoms Soil has a stagnant, rotten egg smell, often noticed when changing holes

Black layer Dealing with the problem To cure the problem the issue of lack of air in the soil needs to be addressed. This is done by surface aeration, improvement in surface drainage (by installing drains etc.) In extreme cases the working of ground charcoal into the soil surface after aeration can help by absorbing and neutralising the toxins

4. Type 3 Fairy ring- caused by fungal activity under the soil 4. Type 3 Fairy ring- caused by fungal activity under the soil. These toadstools produce spores to help the fungi reproduce and spread. Treat by brushing off as they do not harm the turf grass.

5. Type 2 Fairy rings They are caused by fungi in the soil in which the turf is growing. Although caused by fungi they are not classified as a turf disease because they do not actively attack the grass plant. Type 2 Fairy rings produce a single band of stimulated grass growth. Control- use of wetting agents can reduce the effect. If a real Problem an approved fungicide can be used

6. Frost damage- caused by driving/walking on frozen turf 6. Frost damage- caused by driving/walking on frozen turf. The plant cells are frozen and break when walked on brushing the plant. Treatment none- Prevent by closing course in frozen condition if possible.

7. Hydraulic oil spill burn- hot oil leaking from drive system has scored the grass and the oil maybe toxic to roots (depending on oil used) Treatment – if possible soak up excess oil with absorbent material (e.g. activated charcoal activated and calcined clay fines. Then spike area with a hand fork and apply wetting agent to help break up oil.

8. Thatch fungus- Fungi under the surface are breaking down thatch, this leads to slight depressions in the surface and fungal mycelium on the surface. Treatment – reduce thatch levels by aeration and scarification.

Thatch fungus (or Superficial fairy ring) Symptoms First seen as small dark green patches the size of a tennis ball (8 - 10 cm across). These increase to the size of a dinner plate (25 - 30cm across). A dense creamy white mycelium can often be seen on the surface of the soil. This has the characteristic smell of mushrooms. The fungus is present on the surface, in the thatch layer, and in the soil just below. It consumes the thatch and organic matter, releasing readily available nitrogen which causes the dark green appearance. The turf surface in the affected area sinks leaving depressions which make play difficult. Note it does not kill or harm the grass directly but does affect surface quality Influencing factors Lack of adequate thatch control, overfeeding and over watering can encourage the disease.

Control measures for thatch fungus Routine scarification, hollow coring and correct management of nutrition and irrigation are the main methods of control. The depressions can usually be levelled by applying several light top dressings.

9. Thatch- soft layer of dead/dying plant material 9. Thatch- soft layer of dead/dying plant material. Produces a soft, spongy surface. Also promotes shallow rooting. Treatment- remove by scarification and aeration, apply sand top dressings and reduce fertiliser input (nitrogen)

What is Thatch? It is a build up of organic matter on turf surface (from dead grass, shoots, roots and leaves) Should we have any thatch? We need enough thatch to prevent injuries from falls on sports Surfaces such as Rugby pitches etc. A small amount of thatch can be beneficial as it helps prevent damage from ball impact. However too much thatch can cause many problems

Problems with thatch It creates a soft spongy surface reduces ball bounce and slows ball roll. Encourages shallow rooting of the sward Encourages diseases (due to the moisture it holds) Can lead to pitch mark problems on golf greens It can encourage earth worms It can slow surface drainage

Dealing with thatch Reduce by hollow coring Reduce by scarification Help prevent by Correct fertiliser application Not over watering Good aeration (air in soil encourages bacteria who break down thatch) Good drainage Regular scarification

10. Water logging- Caused by poor drainage 10. Water logging- Caused by poor drainage. Treatment – improve drainage with deep aeration and check any drains are not blocked.

11. Nutreint deficiency – the views in the leaves have yellowed 11.Nutreint deficiency – the views in the leaves have yellowed. In this case the deficiency has been caused by a lack magnesium. Treatment for all nutrient deficiencies is to identify the deficiency correctly then apply the required fertiliser to deal with the problem. NB: Always check soil pH as this can a big effect on the uptake of nutrients by plants, the best pH for turf grass growth is between 5.5 and 6.5.

Nutrient Stress symptoms Common nutrient deficiency symptoms Light green leaf – Nitrogen or Iron Yellow tips to leaf- Potassium Red tips to leaf– lack of Calcium or Magnesium Red leaves – lack of phosphorus