It seems to me that potential changes to European Union legislation have surrounded turf management for much of the last decade, with many threats, whether real or perceived, to the availability of Plant Protection Products. We have finally come to an end of the speculation as the new Plant Protection Products (Sustainable Use) Regulations came into force on 18 July 2012. The Sustainable Use Directive (Directive 2009/128/EC) is intended to introduce a greater degree of uniformity on the requirements for good practice in pesticide use across the EU. It aims to achieve the sustainable use of pesticides specifically by ‘reducing the risks and impacts of pesticide use on human health and the environment and promoting the use of integrated pest management and of alternative approaches or techniques such as non-chemical alternatives to pesticides’. Therefore, at least for the foreseeable future, we know what legislation affects Plant Protection Product use on golf courses.
As part of the Sustainable use Directive, all EU Member States must prepare a National Action Plan. The Plan describes the measures taken to meet the requirements of the Directive and achieve sustainable use of Plant Protection Products. Within Amenity, this could involve, for example, following the recommendations of a qualified advisor encompassing all elements of integrated pest management to minimise the need for pesticide use. The overall reduction in pesticide use would then be identified in future pesticide usage surveys.
Therefore, for golf courses, we now must assess all aspects of our management and their effects on pests, weeds and diseases as well as the playability of the turf surface. It would be impossible in the scope of this article to provide great detail into specifics but there are various elements worth considering. Excessive organic matter is, in my opinion, probably the greatest single factor in encouraging disease development on golf course greens. It is the food source and home for many pathogens, such as Microdochium nivale (causal agent of microdochium patch) and Colletotrichum cereale (causal agent of anthracnose). “
Organic matter provides a home for disease.
Moisture would be the second most important influence on disease development on golf greens. Thatch also holds a lot of moisture at the surface during wet periods, providing not only a poor playing surface, but the water needed by germinating spores to infect the grass plant and so increase the potential for disease development. Added to this, moisture lying on the grass surface can increase the potential for infection. Any methods employed to remove moisture, such as switching, encouraging morning sunlight penetration and good air flow or use of dew removal products, will help reduce the severity of disease infections. There is also a lot of evidence to show that golf greens dominated by less desirable grass species, such as annual meadow-grass (Poa annua), tend to have higher moisture contents than those dominated by the more desirable grass species. These greens tend to favour development of diseases, such as microdochium patch, most likely as a result of higher moisture content and the increased susceptibility of annual meadow-grass.
The next level of minimising disease would be assessing inputs. From a fertility point of view, the timing of application, type and amount of fertiliser used and release pattern are all important considerations. Research has shown that ammonium sulphate based fertilisers are optimal for maintaining golf greens dominant in desirable grass species and so result in the least amount of disease. The amount of nitrogen required obviously depends on the dominant grass species present. The release pattern can help relieve diseases, such as red thread, shown to be kept minimal in trials using controlled release fertiliser. The effects of other nutrients also needs to be considered, such as maintaining good potassium supplies, which helps to increase wear tolerance and is responsible for water movement into and out of stomata. Iron is also incredibly important in the battle against pathogens. Most pathogens grow less favourably in the slightly more acidic rootzones favoured by bentgrass and fescues. And so, in my experience, as well as reducing the pH in the immediate rootzone, iron also hardens off the grass plant making it less susceptible to microdochium patch.
The final layer of defence is Plant Protection Products, taking us back to where this article began. Using the best product at the correct time, applied by trained staff using a properly maintained and calibrated sprayer, will afford us not only optimal pest, weed or disease control but with the most environmental and financial benefits. When using products, we must only treat the target area, ensuring we protect any adjacent water courses or different surfaces. We need to observe stewardship schemes, such as ‘Say no to drift’ which specifies how chlorpyrifos should be applied for leatherjacket control. We must also minimise use in specific areas, such as areas accessible by the public and use on very permeable surfaces.
Whatever the control strategy, the risk and appropriate level of control of each pest, weed or disease needs to be determined.
For example, the acceptable level of disease on a local authority playing field frequented by school children may be very different to that acceptable on Championship golf greens and so a very different control strategy could be required.
In summary, for those already using best practice, the recent changes to legislation will probably not affect how you conduct your pest, weed and disease control. Producing healthy turf, managed appropriately using integrated pest management, is still the optimal way to achieve turf surfaces least conducive to pest, weed or disease outbreak and most conducive to a good game of golf.
The views expressed in this article are those of the author and not, necessarily, those of The R&A.