Analysis – getting the most out of it
Physical analyses are of critical importance when sourcing materials for a new construction, or for reconstructions, to ensure the consistency of the materials brought on to site and to check that they conform to the required specification. In addition, physical analysis can be completed on established rootzones to check that they are continuing to perform as constructed and to identify likely future problems.
Chemical analysis is frequently completed on rootzone material and increasingly on leaf tissues to identify nutrient availability within the rootzone and nutrient uptake in to the plant. This analysis can be used as an indicator of what nutrient application is required and when, in order to achieve the maximum potential of the sward.
There are several laboratories across the UK that offer these services and it is advisable to select one that is familiar with amenity situations and specific turfgrass analyses. In addition to the routine nutrient and full elemental analyses, analysis for toxic elements and water analysis can also be completed by these laboratories. These analyses won't tell you what to do as a turf manager but they will help you to decide on product application and timing and alert you to potential problems that may be developing.
The usefulness of these analysis results can only ever be as good as the samples that are received by the laboratory. If you don't send them a representative sample, the results will be of little use to you. The responsibility is therefore on you to ensure that what you send off for analysis is what's required to give you the information that you need.
The same is also true for pest and disease analysis. If the material received for analysis is not representative of the problem, the results may be incomplete and of limited use in dealing with the problem. However, a complete pest or disease analysis will tell you what the current problem is and also highlight possible reasons for the development of that problem and therefore help with amendments to your cultural maintenance programme.
It may also be possible to inform you of additional and potential problems that you would otherwise be completely unaware of. It is important to identify a pest or disease before any control options are implemented and certainly before any plant protection product (pesticide) is applied, as this will ensure application of an effective active ingredient. So, if you don't know what is causing a problem, how do you know the best way to send a sample for analysis?
We can break down pest and disease problems in to two main groups, invertebrate pests and disease (we won't include vertebrate pests such as rabbits, moles, badgers and geese as they are seldom sent in the post for analysis).
Plant parasitic nematodes
Nematodes are an extremely diverse group of unsegmented roundworms that can quite correctly be regarded as invertebrate pests. However, they are also microscopic, directly attack the plant tissues, cause adverse changes to the physiology of the plant and initiate the development of disease. Therefore, like fungi, they can also be regarded as disease-causing organisms. With regard to sampling for nematode analysis, they will be considered separately from other invertebrates and from the fungi that cause disease.
Generally, if your turf is being colonised by invertebrate pests, you can find them living in the rootzone but you may not necessarily know what they are. If this is the case, gather up a few of the larvae and put them in to a sturdy (preferably plastic) container, something like the old 35mm film cases is ideal, and fill the rest of the container with rootzone or plant material to prevent the larvae from being shaken around too much whilst in the post.
Putting several of these invertebrate larvae in a plastic bag inside a normal envelope is not a good idea as they arrive at the laboratory more like an invertebrate soup than any living creature - I have received them like this so I know. It is also acceptable to send a turf sample taken from an affected area, such that the larvae will be contained within the naturally infested turf or rootzone. In this case, the sample should be packed tightly in to a cardboard box or padded envelope for postage. For some invertebrate pests like the frit fly larvae that are much more difficult to see, I would recommend that you send a hole changer sized turf sample, with rootzone down to approximately 50 mm (2 inches) so that the laboratory can check for the presence of the pest larvae using a microscope.
A hole changer core sample is also ideal if you think that your turf problem is likely to be a fungal disease. This size of sample shows what grasses are in the sward, which grass type(s) is(are) affected, provides numerous intact plants for analysis and allows a greater chance that the sward will remain uncontaminated by the rootzone material during postage.
The core should be taken to the depth of the roots (or 150 mm (6 inches) max.) but not less than 50 mm (2 inches). However, where you decide to take the sample from is equally important. If the damage to the sward is developing in obvious circles or patches, it is best to take a core sample from the leading edge of the symptoms, such that half of the core shows damaged turf and half shows the unaffected turf around the outside.
If you are in any doubt, or if the symptoms change noticeably over time, send more than one core sample and indicate to the laboratory that they are all examples of the same disease problem. However, if the symptoms are more general across large areas of the sward, take one or more representative samples randomly from the turf. Hollow tine cores are not suitable for fungal disease analysis because they provide very few intact plants, don't show how the problem appears on the sward and don't give a clear impression of sward composition or the grass type affected.
Occasionally, soil profile samplers are used to remove material for fungal analysis. This type of sample is acceptable if it is not possible to take a hole changer core from the area.
However, you have to be aware of the limitations in analysis that can be completed on this type of sample. As with the hollow tine cores, many of the plants in this type of sample will be severed from the roots and the number of intact plants available for analysis will be reduced. Due to its size, this sample is more likely to fall apart whilst in the post, allows contamination of the sward with the rootzone and masks any potentially reportable problems that may have been apparent down the profile.
For fungal disease problems, it is imperative that the turf sample is not wrapped in plastic. If the sward is in contact with plastic, it will sweat and secondary, saprophytic organisms are likely to flourish and mask the presence of the primary pathogen. The turf should be wrapped tightly in dry newspaper and then packed in to a box or a padded envelope (the smallest necessary to contain the sample) and sent by next day delivery or by first class post. To help in confirming the diagnosis, it is always useful to include a brief history of the problem; age of sward, grass type present, when the symptoms were first seen, how they appeared and how they have developed over time, what products were applied prior to and following symptom expression and if this is the first time these symptoms have been seen on the turf.
It is extremely helpful for the laboratory to see a picture of the problem as this gives a clearer indication of symptom development than any description could ever provide. If possible, email a picture of the problem to the laboratory and inform them that you will be sending a turf sample for analysis.
Problems caused by plant parasitic nematode are being reported more frequently as our understanding increases about the potential of these invertebrates to cause damage to a range of amenity turfgrasses. The symptoms that these pests can cause will vary dramatically depending on the type of nematode present, its current population and the type of grass being affected. However, analysis of turf or rootzone material for the presence of plant parasitic nematodes is best completed on bulked hollow tine core samples taken to a depth of at least 50 mm (or the depth of the roots) and packed in to a sealed plastic bag. The total mass of bulked cores should be about 0.25 kg and ideally, two samples should be sent. One sample should contain cores removed from affected areas of the turf and the other should contain cores taken from apparently unaffected turf that will allow background nematode populations to be determined.
It is possible for plant parasitic nematodes to be present within the rootzone, or inside the plant, at levels that are too low to cause damage. For this reason, it is important to determine the background population level against which the populations in the affected sample can be compared. It is crucial that the nematodes don't dry out whilst they are in the post and it is for this reason that they need to be in a large enough mass of rootzone and contained inside a plastic bag.
The natural rootzone moisture should be sufficient to maintain them and no additional water should be added to the sample prior to posting.
If symptoms of damage develop on the turf which don't fit neatly in to the above categories, speak to someone who will be doing the analysis for you, explain the symptoms and ask for guidance on the most appropriate samples to send. If in doubt, I would always suggest sending a hole changer core sample wrapped in newspaper.
This can be used to identify, or dismiss, the possibility of fungal disease, will indicate possible problems with the rootzone that could be causing or contributing to the sward damage and can also be used to give an indication of invertebrate pest problems and plant parasitic nematode infections. If nematodes are suspected from this initial analysis, it may be necessary to follow up with bulked hollow tine core samples to identify the background types and populations and identify more clearly which nematode is likely to be the cause of the problem.
On occasion, it may be necessary to check the turf or the rootzone for contamination either from accidental or deliberate damage. Fortunately, deliberate vandalism is not too common but, when it occurs, it is important to know what has been used to damage the turf so that the most efficient and effective remedial treatments can be implemented as quickly as possible. Similarly, accidents happen with contaminated spray equipment, over application of a product or application of the wrong product to the turf.
If you suspect that the turf has been damaged there are a couple of things that you should do straight away. Firstly, take a photograph of the symptoms so that you have a record of where the damage is and, if it does subsequently develop over time, you have an accurate record of how the symptoms have changed. If you have long-term problems with turf quality, again, these early photographs will help you to confirm whether the weak sward is in the same area as where you had suspected damage. We all have enough things to remember on a day-to-day basis without having to remember things that can be recorded simply as a photograph. Photographs are an excellent tool for recording pest and disease outbreak too, but it's surprising how infrequently they are used to record such problems.
Secondly, you can complete a very quick growth test to determine if there is likely to be a problem in getting seed to germinate on the damaged area. Remove several small hollow tine cores or, if easier, a hole changer core sample from the damaged part of the turf and, also, take a similar sample from a known healthy area as a comparison. Place the damaged and healthy material in to separate plastic plant pots, label them so that you will know where the sample material came from and sprinkle a few mustard seeds on to the surface of each (you can buy a packet of seed at any garden centre and once opened, seal the packet and store it in a cool place).
Gently press the seed on to the sample material, lightly water them and cover each pot with a sheet of plain paper to exclude light until the seed has germinated. After a couple of days the seed should have germinated and the paper can then be removed. The material in the pots should be kept moist by regular, light watering and the relative growth of the mustard plants on each sample will tell you if there is likely to be a problem with over-seeding the damaged area. If the seed fails to germinate or if the plants on the damaged sample grow in a slow or deformed manner when compared with the normal sample, you know that there is still some product in the rootzone that will adversely affect grass growth. Results from this test should be available to you within 7 days.
If you have noticed a discolouration to the sward but are uncertain as to whether the turf has been damaged, it may be worth taking a couple of small, 2cm diameter core samples from the affected area, sealing them in a plastic bag and storing them in a freezer. These samples can be kept for months if necessary and, if the cause of the problem does eventually need to be identified, they can be sent to a suitable laboratory for analysis. In the natural turf situation, applied products, including pesticides, will be broken down over time and if material has not already been taken and frozen (or already sent to the laboratory for analysis), it may prove impossible to detect the cause of the damage.
If you suspect damage or vandalism and don't want to wait and see what may happen to the sward over time, you can send material straight away to a chemistry laboratory such as Mountainheath Services Limited, Hertfordshire, where they can analyse plant tissues and rootzone samples to identify or monitor levels of chemical contamination.
If you are going to do this, send the material to the laboratory as quickly as possible, as soon as damage is suspected (or send your stored, frozen material) and, depending on what is being analysed for, it is often possible to get same day turn around of results. This could be crucial to the rapid recovery of the playing surface. Again, speak to someone at the laboratory, explain the problem and they will advise you on the most appropriate type of sample to be sent for analysis and the quantity required. Knowing who you can turn to for help if something does go wrong, should offer peace of mind.
Regardless of what analysis you are seeking or where you are sending material for analysis, make sure that you label the samples appropriately so that when you receive the results, you can relate them to the turf area that was sampled. Also, don't forget to enclose your contact details so that the results can be sent out to you. You may smile at this, but you would be surprised how often it is necessary to 'match up' samples received to persons having sent material for analysis.
This variety of turf and rootzone analyses is offered to you by a number of laboratories to help you in your position as a turf manager. They should be considered as another tool for you to use to help you make informed decisions about your maintenance programme, but they can only be helpful to you if the correct sample material is sent for analysis. If in doubt, ask.
Kate Entwistle, The Turf Disease Centre, 01256 880246, Kate@theturfdiseasecentre.co.uk