Module 6:

6.2 Turf problems and controls

1   Disease control

Where turfgrass diseases are a problem and regular turf maintenance practices have not managed to control or reduce the incidence or spread of a disease then the use of an approved fungicide will usually prevent or cure any further spread.

Practices that can help reduce the likelihood of an attack and reduce the spread where it has occurred, can include the following:

1. Keep the turf on the drier side - do not overwater nor water too frequently.
2. Remove dew early in the morning to reduce leaf wetness during the day.
3. Encourage a deeper rooting sward through good aeration practices. This helps contribute to a more resilient sward.
4. Maintain a healthy, strong sward by applying appropriate quantities of fertiliser.
5. Avoid organic fertilisers during low growth periods as this can encourage a softer turf that is more susceptible to disease attack.
6. Reduce or avoid neutral to alkaline reacting fertilisers as this will be more likely to encourage disease attack and spread.
7. Avoid applying relatively high levels of nitrogen after the end of August to early September, and do not force growth at any time of the year, encourage gradual development of the grass sward to reduce potential for plant cells that are expanded and weak which will increase the likelihood of disease penetration.
8. Apply adequate amounts of biostimulants to counter low levels in sand-based pitches.
9. Do not mow too short as this reduces rooting depth, density and sward resilience. Do not overstress the sward with short mowing as this will make it more susceptible to disease attack.
10. Try not to remove move than one-third of the leaf per mowing session, otherwise the grass plant will be weakened.
11. Where grass clippings are let fly and they clump together on a pitch then disperse any grass clumps to avoid creating moist area of smothered turf that are more susceptible to disease attack.
12. Where mowing doesn’t take place on a regular basis, especially during the autumn to early spring period, consider the use of a drag brush to help keep grass leaves more upright and improve air flow amongst the leaves.
13. Keep the surface layer clean of dead and decaying organic matter through scarification, metal tine raking and verticutting. This helps to keep air flowing between the basal area and grass leaves and reduces relative humidity within a surface layer.
14. Do not scarify or verticut where undue stress will be exerted on the sward. Ensure the sward can cope with and easily recover from any mechanical activity applied to it.
15. Do not smother grass leaves with top-dressing. Ensure a dry top-dressing is well worked in and applied in dry conditions.
16. If possible, use top-dressings that have been sterilised, ideally having eliminated and weed seeds and fungal spores that might have been present.
17. Do not sow seed to a very high density as this will encourage seedling disease.
18. Where covers are used to aid seed germination and initial establishment, ensure adequate air flow is regularly given to the seeds or young grass as relative humidity can become a problem under some ground covers.
19. Aim to reduce the amount of shade on a pitch.
20. Apply any approved fungicides where disease activity is higher than a planned threshold or damage is trending towards an unacceptable level.

2   6.2.4 Disorders

The main question often asked is, ‘Can a football pitch really suffer from a disorder?'

The simple answer is yes.

Conditions that are considered disorders are mostly the effects of unsuitable environmental conditions, which may have arisen from incorrect maintenance practices, and these can include a hydrophobic soil (one that doesn’t well very well), an anaerobic soil (a lack of available air, being wet), extreme cold or high temperatures, drought, a nutrient deficiency, fuel spillage, hydraulic oil leakage, or incorrect pesticide applications, although there are many more possibilities.

The most significant and often problematical ones that are considered disorders are dry patch (hydrophobic conditions - this is where the soil repels the water making it difficult to be retained within a soil profile) and black layer (this is a lack of available air within the soil or surface layer which produces a dark and wet organic layer in which rooting is very poor). These would be more unusual for most soil-based pitches, although dry patch on sandy soils might be something to be aware of, whilst black layer is something that would only really be encountered on high sand content pitches.

The use of wetting agents should be considered where dry patch might exist or is likely to arise, whilst improving aeration, amongst various other activities, is the key activity for the correction of black layer.

We’ve covered quite a lot already on turf problems and their controls, so now would be a good time to review some of the learning with this 10 question quiz.