Pesticides: Issues with Use

There are many issues concerning the use of pesticides, however, the need to make a decision that provides a compromise between the benefits and the disadvantages is frequently made by the end-user.

This is especially pertinent where there is no clear-cut decision that can be made and this is often the case when trying to weigh up the use, or not, of a pesticide, or plant protection product.

Resolving the best option in relation to benefits and disadvantages can be fairly complex as there will often be economic, environmental and social aspects and different trade-offs to consider. Integrating these three aspects of sustainability to achieve manageable and acceptable outcomes can often be complex and problematic.

All too often ground staff will opt for the use of a pesticide to control a disease or pest, which is quite understandable if the threat is current and severe, however, it is essential that good turf management practices are implemented at all times as this will reduce the likelihood of severe attacks.

Determining a best option is a value-laden term and will mean different things to different people and this is dependent on and influenced by many factors.

Significant economic and social benefits have been identified with the use of pesticides, especially from an agricultural perspective, including:
• Improving or safeguarding crop yields.
• Ensuring reliable supplies of crops throughout the year.
• Ensuring the availability of lower cost, quality food throughout the year.
• Making more efficient use of land area.
• Being an important contributor to employment and economic activity.

The argument for the beneficial use of pesticides in horticulture and turf management is centred on a number of areas:
• Maintaining a relatively weed free sports turf surface, through the use of selective herbicides.
• Controlling weed growth within established ornamental beds, through the use of non-selective herbicides.
• Controlling the growth and spread of weeds in pavements and kerbsides, through the use of non-selective herbicides.
• Maintaining a disease free turfgrass surface on high quality ornamental lawns and sportsturf surfaces.
• Reducing damage caused by pests, especially leatherjackets and chafer grubs on sports and high to medium quality amenity turf surfaces.
• Controlling pest infestation on a range of plants, including, flowers, fruit and vegetables.
• Controlling the spread of fungal diseases on a range of plants, fruit and vegetables.
• Controlling the spread of invasive species, as identified in The Wildlife and Countryside Act 1981, e.g. Japanese Knotweed, Giant Hogweed.
• Providing a cost-effective, less labour intensive, service.
• Providing an increased, or optimal, carrying capacity for a turfgrass surface,
• Maintaining a high standard of surface.
• Maintaining sports surface playability.
• Reducing match cancellations.

The negative impact of pesticides on human health and the environment is also recognised and this includes:
• Acute and chronic health effects by direct exposure to workers.
• Indirect exposure to consumers, resident and bystanders resulting in potential risks to their health from spray drift and pesticide residues on food or water supplies.
• Environmental harm caused by spray drift, leaching or run-off; these can cause localised air pollution, as well as soil and water contamination.

Serious harm to wildlife has resulted from either incorrect use of a pesticide, especially where the wider and specific impact was misunderstood or where incorrect, or irresponsible, application has taken place. Some pesticides are especially harmful to pollinating insects and some of these have been withdrawn from use, for example, neonicotinoid pesticides.
Lu, C., Hung, YT. & Cheng, Q. A Review of Sub-lethal Neonicotinoid Insecticides Exposure and Effects on Pollinators. Curr Pollution Rep 6, 137–151 (2020).

In addition to physical harm to humans and wildlife, misapplication can result in a poor visual appearance to an area that can increase the perception, in the eye of the general public, of some users being irresponsible and / or not knowing what they are doing.

Turfgrass surfaces that are constructed to a high sand specification will be more prone to pesticide (as well as fertiliser) leaching than soil and clay-based constructions, so managers will need to consider how to manage any potential drainage leachate at the planning and design stage of new constructions.

Where good practice is undertaken the leaching or run-off of pesticides to watercourses, should be a low-risk activity. Good practice can include:
• Applications being carried out in accordance with manufacturer’s instructions,
• Appropriate training, certification and periodic skills and knowledge updating,
• Having buffer zones outside of the spray area and avoid spraying near water,
• Optimum weather conditions prevailing during application, and
• Correct cleaning and wash-down, as well as storage of equipment after use.

The rate of decomposition and persistence of a pesticide within a turfgrass or soil situation can vary considerably, especially as the interaction of a pesticide with the environment following application is complex and diverse. Research has shown that, following correct application, some of the pesticides used within the turfgrass industry are rapidly broken down, with minimal leaching. An established turf effectively acts as a sponge, especially where thatch is present within the soil profile, and this can assist in degrading the applied chemical before it reaches any watercourse.
(1. Clark, J.M & Kenna, M.P. (Eds) (2000) ‘Fate and Management of Turfgrass Chemicals’, ACS Symposium Series 743, American Chemical Society
2. Balogh, J.C. & Anderson, J.L. ‘Environmental Impacts of Turfgrass Pesticides’, pp221 – 354, in Balogh, J.C. & Walker, W.J (Eds) (1992) ‘Golf Course Management & Construction. Environmental Issues’, Lewis Publishers)

The main health risks where pesticides are used as intended would appear to that of the user rather than the general public. (Cook, T. W. & Vanderzanden, A.M. (2011) ‘Sustainable Landscape Management: Design, Construction and Maintenance’, Wiley, p107)

Excessive application, as well as the use (indiscriminate in some cases) of pesticides that are now banned or restricted, as well as users and managers not having a full understanding of the interaction a pesticide had with the wider environment, has contributed to serious harm to habitats and wildlife and has quite rightly contributed to the concern of environmentalists and the general public to the use of chemical pesticides.
(1. Craig, A. (2004) ‘People’s Pesticide Exposures’, Pesticide Action Network UK;
2. Harvey, G. (1998) ‘The Killing of the Countryside’, Vintage
3. Lovegrove, R. (2007) ‘Silent Fields. The long decline of a nation’s wildlife’, Oxford University Press, pp143, 241 & 248
4. Begon, M., Harper, J.L. & Townsend, C.R. (1986) ‘Ecology: Individuals, Populations and Communities’, (2nd Edition) Blackwell Scientific Publications, pp557 – 56)

These genuine concerns have to be addressed through the responsible and safe management and use of pesticides and this must be a priority for the grounds care industry.

Cost-benefit analyses can be carried out for the use of pesticides to control weeds in crops, with the quantity of weeds present within an arable crop being used to estimate the loss in yield if no method of control is carried out. This can be more easily related to an economic cost-benefit analysis; however, if a comparison is to be made to include the social and environmental aspects then this makes a decision that much more difficult as valuing these can be more of a subjective judgement than where a purely financial one is used. (Rowell, D.L. (1994) ‘Soil Science. Methods & Applications’, Prentice Hall, p310)

Estimating a realistic economic loss from a turfgrass surface can be problematic in most cases. It would be rare for a turf surface to be taken out of action due to weed infestation or pest or disease damage. The most likely outcome is one of a loss of surface quality, with a reduction in visual attractiveness and a poorer, but still safe, playing experience. The cost benefit analysis in these circumstances will be more to do with the reduction in playing experience and surface quality rather than loss of income from postponed or cancelled games or events.

Good management is often seen as advocating against the use of pesticides unless there is a strong justification, with the least environmentally damaging chemical being chosen for the control of the target organism or plant where pesticides are needed.
(Watkins, J. & Wright, T. (Eds) (2008) ‘The Management & Maintenance of Historic Parks, Gardens & Landscapes’, The English Heritage Handbook, p.226)

If society were to accept the negative impacts of insect, fungal or weed infestations as part of a natural cycle, without human interference, then there would be no need for the use of pesticides. For the majority of people this would not be an acceptable stance as there is a need to provide food, flowers, sporting surfaces or amenity areas that are provided in sufficient quantity, to a suitable standard, have visual acceptability and are considered as being fit for purpose. However, the question arises within a sports turf situation of what is really needed and is fit for purpose. Has the social desire for pristine playing surfaces gone too far in that natural cycles are poorly considered within a management regime? Accepting blemishes and variations in surface quality provides for an understanding of nature and how it ebbs and flows in its impact on a turfgrass surface. Many who argue for unnatural blemish free surfaces will often have a financial interest, in particular by those who produce, market and sell pesticides, as well as organisations that accept advertising and monies for surveys from the aforementioned. Is it really acceptable for those with a significant monetary interest unduly influence the majority who see environmental responsibility and environmental sustainability as a key foundation for modern grounds management?

Social aspects such as a significant reduction in visual quality of a flower display to a weed-infested pavement can impact on a society’s interaction with, and perception of, their local environment. Places, especially urban ones, which become overgrown and appear to be neglected, can encourage vandalism and anti-social behaviour, starting a decline in the economic, environmental and social aspects of a local community. The social and cultural impacts of a degraded natural environment can significantly influence the well-being of individuals and whilst these are often subjective value judgements, green space areas have been shown to increase social interaction and satisfaction within a community, as well as provide significant health benefits.
(1. Jennings, V., & Bamkole, O. (2019). The Relationship between Social Cohesion and Urban Green Space: An Avenue for Health Promotion. International journal of environmental research and public health, 16(3), 452.
2. Public Health England, (2020) ‘Improving access to greenspace: A new review for 2020’
3. SDC (2008b) ‘Health, place and nature. How outdoor environments influence health and well-being: a knowledge base’, Sustainable Development Commission)

The natural environment, which includes parks, gardens and other man-made landscapes, also provides space for spiritual connection and contemplation for many people in their quest to understand their place within nature. Maintaining these areas to meet everyone’s needs is a challenge, but one that may be made easier through the careful use of plant protection products. (Palmer, J.A. ‘Spiritual ideas, environmental concerns and educational practice’, pp146-167, in Cooper, D.E. & Palmer, J.A. (Eds.) (1998) ‘Spirit of the Environment’, Routledge)

A playing surface that is infested with weeds, pests and/or disease will not only look unattractive, but also can affect the playing performance of a ball or bowl. This is not going to be acceptable to many people, especially to players and televised audiences.

Determining what level of weed, pest or disease damage, or infestation, is acceptable, can involve many perspectives. There is often little need to have a surface that is totally free of these undesirables, but there is a requirement to manage the content to an acceptable level. Performance standards for most turfgrass surfaces, including amenity grass surfaces can be used to assist in agreeing what is an acceptable level of infestation for specific situations. (British Standard BS 7370-3:1991 ‘Grounds maintenance. Recommendations for maintenance of amenity and functional turf (other than sports turf)).

The use of a pesticide to control, which often just means temporary control, weeds, pests or disease within a turfgrass surface involves more than a straightforward yes or no answer for spraying or not. Many factors need to be taken into account when making a decision, not least the question of how will the action that is taken contribute to the sustainable management of the turfgrass surface.