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

Sports turf disorders A. Non living threat to turf B. Does not infect living or dead grass C. Does not spread from one affected area to another D. Physical, chemical or mechanical damage

Common disorders of sports turf 1) Dry Patch 2) Black Layer 3) Pesticide/fertiliser damage 4) Compaction 5) Lack of nutrients 6) Water logging 7) Thatch

Dry Patch What is it? Water repellent root zone which can be caused by fungal activity or an organic residue on the soil/sand partials. Symptoms Grass changes colour (blue/green first) then browns and wilts Water runs off the affected area

Dry patch Cure Wetting agents can be used to help reduce problem Spiking when irrigating to aid water into the soil

Pesticide/fertiliser damage Symptoms Scorch from the fertiliser or pesticide (burning of grass leaf) Prevent by Check equipment before use. Ensure operator is well trained Sweep up spills of fertiliser and water the affected turf well.

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

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).

Thatch

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 1. It creates a soft spongy surface reduces ball bounce and slows ball roll. 2. Encourages shallow rooting of the sward 3. Encourages diseases (due to the moisture it holds) 4. Can lead to pitch mark problems on golf greens 5. It can encourage earth worms 6. It can slow surface drainage

Dealing with thatch 1. Reduce by hollow coring 2. Reduce by scarification Help prevent by a. Correct fertiliser application b. Not over watering c. Good aeration (air in soil encourages bacteria who break down thatch) d. Good drainage e. Regular scarification

Black layer What is it? In soils with and poor drainage and little aeration anaerobic bacteria produce hydrogen sulphide this reacts with 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

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

Scalping Cause- height of cut too low Avoid by checking height of cut before use, care use of mower (not dropping or raising units to early/late

Water logging This is caused by severe soil compaction and or poor drainage/blocked drains Treatment- aeration (spiking/slitting) installing or maintaining drainage systems.

Oil spill Symptoms Brown area of turf caused by the heat of the oil as it made contact with the grass leaf. Prevention and cure Check machines carefully before use If a leak occurs apply absorbent material such as dry sand to soak up the oil. Remove the sand and apply wetting agent to the area to aid water penetration and break up the oil.

Thatch fungus (or Superficial fairy ring) Symptoms First seen as small dark green patches the size of a tennis ball ( cm across). These increase to the size of a dinner plate ( cm 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.

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 only a single band of stimulated grass growth and/or toadstools. Control- use of wetting agents can reduce the effect. If a real Problem an approved fungicide should be used

Type 3 Fairy rings Type 3 Fairy rings have only produce a ring of toadstools that is only seen at certain times of the year. No control is required

Drought stress This is different to dry patch which affects defined areas. Drought stress tends to affect large areas of the sward surface and is a result of prolonged dry weather and or extreme heat. Symptoms of drought stress Grass goes grey shade of green then brown (not yellow) Grass does not stand back up quickly when stepped on. This can be tested by the “footprint test” this is where the turf is stood on and if the footprint remain visible (see next slide) for more that 10 seconds or so the grass is short of water (this is because the cells in the plant are lacking water and are less turgid than normal (have less internal pressure). Surface firmness increases as the soil dries Amount of grass clippings is reduced Cure Apply wetting agents and irrigate, and or increase the height of cut to reduce stress on grass plant

Footprint test Footprint test – note the footprints have remained due to lack of water in plant leaf