In recent years the number of chemicals available to us as turf managers has rapidly diminished, while expectations relating to turf quality remain as high as ever from stakeholders. Dave Lawrence, Grounds Manager and John Lawrence, Assistant Grounds Manager at Edgbaston Priory Club spoke about the removal of these products, or more specifically, the active ingredients within them, and the plethora of challenges when it comes to achieving the lofty expectations we set ourselves, as well as those set upon us externally.
Such pressures can often lead to knee jerk reactions, and turning to solutions which may not come with all the facts about their long, medium, or even short-term impacts. We should be clear, this is in no way a criticism of practices employed by turf managers, but at some point, we do need to consider the overall impact of the methods we are turning to in order to control the pressures that fall upon our surfaces. After all, how do we know that our short-term solution isn't creating a much bigger long-term problem?
Over the last three years, we have seen Carbendazim, Imidacloprid and Chlorpyrifos removed from sale within the amenity sector, whilst Iprodione is soon to make its way on to the growing list of banned substances which were once readily available to us. Fortunately, there are some alternatives to products like Chipco Green and Interface, be they different active ingredients or general integrated approaches; but more on those later.
However, the big challenge in the industry over the last two years has been dealing with organisms below the surface, rather than above it. The removal of the active ingredients used to control Chafer Grubs, Leatherjackets and Casting Worms have left turf managers scrambling to try and find other ways of reducing said pests impact on the playability and quality of the surfaces we look after.
Looking after a surface where consistency is key, we thought long and hard about how to control populations of Leatherjackets and Chafer Grubs in the soil profiles below our tennis courts at the Edgbaston Priory Club. The dead patches caused by feeding grubs and larvae chewing away at the roots of grass plants would obviously cause major problems, both cosmetically and in terms of performance. However, we're all also painfully aware of the damage birds can do feeding on the grubs present within a soil profile; the number of bad bounces such a grub buffet could lead to does not bear thinking about for too long!
With that in mind, we've turned to nematode treatments to control the populations of Chafer Grubs and Leatherjackets within our court profiles. Now, we're not going to spend too much time explaining the inner working of nematode control; there are plenty of resources available on the Pitchcare website which do so much more succinctly than we could event attempt to. However, the important facts to note are that nematodes are, essentially, small (extremely small in many cases) worms that are often parasitic in behaviour; that is they live and feed off of a host body until that host body is no longer viable in terms of sustaining the nematode. They, like earthworms, have the ability to respire through their epidermis. There are differences in the specific way that the two species respire, however they both utilise forms of diffusion to take in oxygen and deposit carbon dioxide.
Dave Lawrence (left) and John Lawrence
Now, we should state at this point that we work to an ethos whereby we will not so much as entertain the idea of utilising a product unless there is strong scientific evidence to support our own assumption that the product will achieve the aim we envisage for it. That isn't to say that we don't see the value in trialling new products or techniques, but we feel strongly that there needs to be a strong scientific argument in place to support anything we consider implementing.
On that basis, and after a lot of research, we took the decision to take a 'non-saponin' based route when looking to control earthworm populations which cause worm casts. We have little doubt, having done our research, that saponin based products will have the effect of significantly reducing casting work populations. Of course on the basis of our above criteria, you would maybe assume that we would therefore consider the use of saponin based products on our surfaces. However, further reading began to shed a potentially damaging light on the potential effects of saponins within the soil profile.
Again, we aren't going to spend too much time going over old ground. There have been some excellent articles on saponin products published on the Pitchcare website, including one titled "A cast of thousands or 'purity' of thought?" In short, saponins are simply a plant extract that have a huge number of potential uses.
Saponins are widely accredited as the likely 'active' in the old school Mowrah Meal, though it should be noted that there is no scientific trial evidence to support this assumption. Mowrah Meal, for our younger readers, was a revolutionary product in the early 1900s. Applications would draw hundreds, if not thousands of worms to the surface of the treated area (normally golf greens), at which point they could be swept and raked up, and carted off away from the site, and the piece of turf that the groundsman hoped to protect. Mowrah Meal continued to be used widely until the 1950s when the advent of chemicals such as Chlordane, which killed worms in the soil profile and left inhospitable conditions, in some cases, for decades, became the go-to casting worm protection method.
Since the 1950s, as turf managers, we've had access to a conveyor belt of synthetic pesticides capable of dealing with casting worm problems in one way or another. However, as their number has reduced, more and more people have begun to look for the next generation of 'silver bullets' which will solve the perceived forthcoming crisis. Rather curiously, the next generation of worm control has taken the form of some early twentieth-century approaches, and the soil conditioners that many are now choosing to turn to bear a striking resemblance to the 'old school' Mowrah Meal that phased itself out naturally seventy years ago.
Seventy years ago though, we didn't have the access to the scientific analysis that we do now, and the worry for us is that while we have no access to any specific field trial data regarding the use of saponins in turf management, there are enough points of assumption, borne out of a better scientific understanding, to suggest we should exercise some caution.
There are two schools of thought regarding how saponins deal with worms within the soil profile;
1) Saponins block the worms ability to respire by interfering with the worms epidermal mucus membrane. The saponin dries the mucus out, blocking the pathway of oxygen into the body leading to suffocation and eventually death.
2) Saponins enter the worms, and turns Protoplasm within cells solid. Cell walls begin to 'leak' allowing cell fluids to flow out and ultimately the worm dies.
Should either theory prove correct (and in the context of our decision making it doesn't matter which is correct), this would suggest that the saponins won't just target casting worms; this to us is a major problem. Worms provide so many positives within the soil profile; they are vital to promoting a healthy environment to produce good quality sports turf. Worms break down organic matter contributing to a reduction in thatch, they offer a unique form of aeration and both of these activities result in an increase in the availability of otherwise 'locked' nutrients. Why then, would we want to indiscriminately target all the worms within our soil profile?
Another point of contention we have with the use of saponin based soil conditioners sits with some of the other associated uses saponins are believed to have. For example, saponins are cited in a number of medical papers as bearing anti-bacterial properties. Similarly, there are a number of sources that suggest Mowrah Meal, as well as dealing with worms, possessed not only anti-bacterial properties, but also anti-fungal properties. As a rather prominent aside, saponins are used in a number of natural head-lice treatments. All of these points, whilst not specific scientific trial data, do paint the picture of a product that has properties that require the implementation of some caution.
For example, if saponins are effective in killing head lice, what other insects could saponins effect? Now, don't take this as an attack on saponin based products, or a definitive 'thou shalt not apply saponins' propaganda drive, but surely, we should have all the facts before we select the path we wish to go down; that is the overriding reason we have not ventured down the saponin route, as yet.
Left: Chafer Grub, right: Leatherjackets
For example, one assumption based spanner in to the metaphorical works for us is what would be the effect on the nematodes we apply to control Chafer Grubs and Leatherjackets? Soil borne nematodes, after all, are most abundant in the top 150mm of the profile; they share a number of similarities with earthworms, most notably that they respire via diffusion. Why, if saponins have an effect on earthworms, would they not impact nematodes? Just to complicate things further, trials with tea seed meal pellets in the USA have suggested that saponins have no effect on Chafer Grub beetles or Cut Worms; will they kill indiscriminately or not?! Could applying saponin based products remove casting worms, but also the control for Chafer grubs - nematodes, thereby solving one problem, but exacerbating another?!
Another point that is worth noting; if Mowrah Meal was considered to have anti-fungal properties, why wouldn't the new, and let's face it, similar soil conditioners? Could the anti-fungal, as well as anti-bacterial properties be affecting populations of all sorts of useful organisms in the soil profile?
For example, what if potential anti-fungal, anti-bacterial properties of saponin based products attack the fungi and bacteria, that could be seen as a massive benefit. However, consider that for years we've struggled to produce synthetic products that will deal with fairy rings, yet there are anecdotes within the industry that propose a link between the end of using Carbendazim, and a sudden clearing of fairy ring activity. What if we put another spin on it though, and ask what if it is the introduction of saponin products into the soil profile that is the cause of this sudden fairy ring clear up?
On the surface, this sounds like a wonderful coincidence; the 'silver bullet' that deals with worms and fairy rings! But again, if saponins turn out to be so potent that they are controlling the fungi responsible for fairy rings, what else are they impacting underneath the surface? There is surely a lot of potential 'friendly-fire' going on beneath the ground! The big question for us is therefore, are end users seeing a short-term improvement but potentially creating a much bigger long-term issue. Are we in fact guilty of buying into a product that will eventually turn out too good to be true?
Again, we'll repeat, this isn't aimed at turf managers as a criticism. Innovation only comes from trial and error, and progress only occurs with innovation. The problem we currently have within the industry is that because these 'miracle' soil conditioners are so unregulated, there is no emphasis on manufacturers to produce scientific evidence to pinpoint exactly what the product they are pedalling out is actually doing, or more pertinently perhaps, how it is doing what it is doing, and if there is any collateral damage incurred in the process.
If soil conditioners were subject to the same licensing protocol as pesticides, we'd surely find ourselves with much more clarity than we currently have. Saponin based soil conditioners could be the miracle 'silver bullet' that may 'save the industry.' After all, wouldn't it be wonderful if they dealt with casting worms, cleared up fairy rings and, whilst we're at it, left alone all the beneficial organisms within the soil profile! Until there is some science that debunks our concerns though, you'll hopefully forgive us for sticking to alternative methods.
With our concerns in mind, it's probably only right to look at how we are attempting to deal with the loss of chemical controls. Now the first point to make is that we always attempt to avoid the use of any chemical inputs; where possible, we try our best to avoid using pesticides, for two reasons. First off, it's just good, sensible, responsible practice. We're (hopefully) doing our bit to avoid building up resistance to certain active ingredients, and so when we really need to reach for a bottle from our chemical cabinet, we can be confident that the chemical will be as effective as it should be.
The other reason we avoid chemicals, unless it is absolutely necessary, is because ultimately, there will likely come a time when our available chemical inventory has been stripped to a threadbare minimum of fairly 'weak' products, and we may not have the option to reach for the bottle, so to speak. If we have coping mechanisms in place before the safety net is removed, we can have more confidence in dealing with issues when that safety net is no longer there to catch us, should a problem occur.
Casting worm control has been a fairly effective illustration of this in recent years, for us. While we've still had Carbendazim available up until recently, we've done our best to implement other methods of control; in fact, we've been trying alternative methods for controlling casting worms and their associated mess for the best part of a decade. As we've alluded to above, we always try to find an alternative to chemicals on the basis that there is a good chance the actives we would otherwise rely on won't be around forever. That isn't to say we don't use chemicals at all; that would be untrue! But if we can develop an alternative means before a chemical is removed, we can breathe a little easier when the revocation notices start appearing.
So for example, over the last few winters we have refined our experiments with applications of granular sulphur chips in order to begin acidifying our soil profiles. We began trying to use sulphur chips as a worm control product ten years ago (whilst Dave was still working at Nottingham Tennis Centre), and have been attempting to refine the application timings and quantities since. For this winter, we have settled on a little-and-often approach to applications, whereby we've theorised that regular acidification of the upper profile will discourage the worms from coming to the surface, whilst retaining their presence deeper down. Admittedly, this is not an exact science, but our initial observations have been that although we still have minor issues with some worm casts, they have significantly reduced in number.
Left: Grass being exposed using a dining fork, right: Smeared worm cast
In addition, we've also adapted our maintenance methods in order to try to implement some cultural and mechanical practices which will reduce the impact of casting worms. Before any maintenance (other than dew brushing), we tend to dragmat the courts to disperse and remove as many casts as possible. Even when damp, this tends to remove a lot of the soil casts; we certainly notice them after a few runs as the dragmat gets heavier and heavier! Of course, this relies on us keeping the courts at a reasonable winter height of cut. We'll aim for anything between 12mm and 15mm depending on weather conditions, though we've found the dragmat has worked reasonably well for us as high as 18mm.
Where, after mowing, we have noted some smearing from worm casts, we'll look to break them up on the surface in one of two ways. If the smearing is relatively localised, we find there is nothing better than a regular dining fork for flicking up the compressed soil and exposing the buried grass beneath. Where smearing is more widespread, and conditions allow, we'll take on a pedestrian verti-cutter or scarifier set at +1mm (or thereabouts) to 'groom' the worst of the casts up and expose the buried grass.
Now we're sure people will be hesitant to verti-cut surfaces in the autumn; after all, we've all spent a lot of time and effort attempting to get new seed to germinate and 'thicken up' the sward ahead of the following year's playing season. However, we feel there is now a two-fold advantage in a little bit of winter scarifying or verti-cutting. First off, there is the benefit we've alluded to above; if it helps disperse worm casts, then it's definitely a box ticked! However, thinning the sward a little is also a way for us to reduce disease pressure by improving air movement and reducing the ability of moisture to spread from one plant to another.
Reducing disease pressure is, of course, becoming more and more important given the reduction in the number of fungicide products available to us, including the soon to be removed Iprodione. As we've already stated, we try to use pesticide products as a last resort, so if we can implement a maintenance activity (such as verti-cutting to thin the sward a little), we will. Similarly, we've begun to look more at plant nutrition in order to strengthen the sward throughout the year. For example, this year we're going to go down a path of applying Chelated Iron, along with Maxwell Turf Hardener throughout the winter in order to toughen the sward up and (hopefully) reduce incidence of disease. We've chosen Maxwell Turf Hardener (other products are available!) because of the calcium content, which research shows will harden cell walls; in basic terms, making it harder for disease to infiltrate and infect.
Centre Court - 10 days post feed (Maxwell Turf Hardener & Chelated Iron)
There will be those who will question our choice to include Chelated Iron in our winter feeding programme, especially in the light of research that suggests that Calcium is a much more effective turf hardener than iron, however we have chosen to continue with the inclusion of iron as it has served us well as a turf hardener in the past; with any luck, the calcium will be much more effective and surpass what the iron has delivered for us up until now, but if it doesn't, at least we're throwing everything we've got at keeping the sward healthy. Additionally, there is some vanity in including the iron; the quick green up we are able to induce keeps things looking good, which is vital when the courts are looked at regularly by our members, as well as any visitors to our site.
To complement our winter programme, we'll also continue with a Primo Maxx programme in the summer, along with regular feeding to keep the courts in peak condition. All of this feeding doesn't negate the need for some fungicide inputs of course, and so we also identify our key disease pressure points, and plan in preventative applications to suit. For us, there are two high risk points; pre-tournament in April / May when we start using raincovers, and end of season renovations before we have seeded and dressed; and, therefore, we won't want to go on court to carry out any curative works while the court is growing in.
On this basis, we generally make two preventative applications a year which, combined with a feeding programme which we are continually developing and evolving, has led to us seeing very little disease in the past few years. The moral of the story, as far as we are concerned, is prevention is far better than the cure. Certainly, in dealing with disease, it is a much cheaper route to go down, but also leads to a stronger healthier sward in general.
In many ways, this is similar to our approach to worm control. For years in our industry we have looked to kill (or if we're being politically correct, supress) worms that come to the surface, when perhaps what we should have actually been doing is trying to prevent the casts. Adjusting pH will in our environment (100% rye grass) be beneficial in terms of the health of the sward; after all, rye grass prefers a slightly acidic soil. Additionally, worms dislike acidic environments, so why have we not been trying to address the root cause of the problem, rather than the side-effects caused by the issue.
One of the root causes, ultimately, of casting worms is the hospitable environment which we have provided for them. So, by dealing with the problem, for example the hospitable pH, we can deal with the root cause rather than using products, Saponin based, Carbendazim or otherwise, to try and cure the effect!