Pesticide Usage in Scotland: Local Authority Integrated Weed Control Survey - 2019

Herbicide use data

These data represent herbicide use in 27 Scottish LAs (which collectively account for 89 per cent of the Scottish land area and 92 per cent of the Scottish population). As described previously, it should be noted that two LAs provided partial herbicide use data (for greenspaces only) and a further two LAs provided quantities of pesticides purchased for use in 2019 as a proxy for quantities used.

Herbicide active substances used

The 27 LAs who provided data collectively applied 43.5 tonnes of 31 different herbicide products in 2019 (Table 4). These products contained 12 active substances, combined into 11 different formulations (combinations of active substances) (please see Appendix 4 for definitions of products, formulations and active substances).

Glyphosate was the main formulation used (14,553 kg) followed by glyphosate/sulfosulfuron (360 kg) and diflufenican/glyphosate (171 kg) (Table 4). In relation to active substances, over 15,000 kg of herbicide used was glyphosate, which accounted for 99 per cent of the total herbicide active ingredient weight applied (Table 5). After Glyphosate the most common active substances were 2,4-D, triclopyr and flazasulfuron (Figure 4, Table 5).

"Other" includes aminopyralid, MCPA, dicamba, mecoprop-P and florasulam.

Glyphosate is an effective and widely used herbicide which is used to manage a variety of weeds in the amenity sector. The sector has a limited choice of active substances which are approved in amenity settings. Unlike many other herbicides, glyphosate is systemic and broad-spectrum, effectively controlling both grasses and broadleaved weeds, making it one of the most widely used, cost-effective tools for weed management. Glyphosate has been approved for use in both agricultural and amenity environments for over 40 years.

Whilst there has been some controversy about glyphosate use, this active substance is currently approved for use in both the European Union (EU) and Great Britain (GB). Approval was granted in 2017 following regulatory evidence assessment by Germany and subsequent review by two independent European expert scientific bodies; the European Food Safety Authority (EFSA) and the European Chemicals Agency (ECHA). All assessments concluded that glyphosate met approval conditions for use and did not pose an unacceptable risk to human or environmental health. Glyphosate's EU approval expires in December 2022 and is currently being reviewed. Following EU exit, GB is operating a pesticide regime independently from the EU. To allow time to plan and implement the GB review programme all active substance approvals due to expire before December 2023 were extended for three years. Therefore, the GB glyphosate approval expires in December 2025. The Health and Safety Executive (HSE), which acts as the regulatory authority on behalf of Scotland, England and Wales, will robustly assess the regulatory evidence before providing a GB recommendation on approval. A recent Scottish Plant Health Centre report concluded that loss of glyphosate would be estimated to have an impact on the UK amenity sector of over £200 million per annum⁽⁵⁾.

Methods of application

A method of application was provided for 73 per cent of all herbicide treatments in terms of weight of active substance applied. Where specified, knapsack sprayers accounted for 58 per cent of all applications, vehicle mounted boom sprayers 18 per cent, vehicle mounted lance sprayers 15 per cent and controlled droplet applicators nine per cent (Figure 5). Controlled droplet applicators produce very even spray droplets which can reduce spray drift and improve efficacy. Other methods of application, including rotary applicators, stem injections and Ecoplugs (which are drilled into tree stumps), accounted for less than 0.5 per cent of weight of active substance applied.

"Other" includes rotary applicators, stem injection and Ecoplugs which are drilled into tree stumps. Please note some LAs provided multiple methods of application for herbicide products. Where use could not be attributed to individual methods (16 per cent of the weight applied), these were excluded from the above calculations.

Surface type

Local Authorities were asked to provide information on the type of surfaces herbicides were applied to. The type and quality of data provided varied by respondent. Many LAs were unable to breakdown herbicide use to specific surface types but were able to indicate generally if application was to a range of surface types. For reporting purposes these have been amalgamated into applications to hard surfaces and to soft surfaces. Hard surfaces included roads, pavements, kerbs, paths, playgrounds, car parks and gravel. Soft surfaces included amenity grass/parks, trees/shrubs, woodland, bowling greens, invasive species and sports turf/pitches. In terms of weight applied, surface type data was provided for 86 per cent of all active substances applied. Where specified, 55 per cent was to hard surfaces, 17 per cent was to soft surfaces and 28 per cent was to a combination of both (Figure 6).

Hard surfaces include roads, pavements, kerbs, paths, playgrounds, car parks and gravel

Soft surfaces include amenity grass/parks, trees/shrubs, woodland, bowling greens, invasive species, sports turf/pitches.

Combination is used when the LA provided a list of surface types for each product which included both hard and soft surfaces and it was not possible to determine the weight applied to each type.

In terms of weight applied, surface type data was provided for 86 per cent of all active substances applied.

Reasons for use

Reasons were provided for 80 per cent of use of active substances. Where specified, general weed control (on various surface types) was the main reason given for herbicide use, accounting for 99 per cent of the weight applied. Treatment of invasive species and tree stumps accounted for just over one per cent. The only weed species specified were Japanese Knotweed and Giant Hogweed.

Qualitative data relating to herbicide use

In addition to questions on non-herbicide methods of control, LAs were also asked questions about reasons for using herbicides and steps taken to target and minimise their use.

All of the LAs who responded stated that they used herbicides. LAs were asked to indicate the reasons for their use and to rank these in order of importance, with 1 being the most important. The mean rank of herbicide use reasons are presented in Figure 7 and Table 6. Invasive weed control and visual appearance were the main reasons for use of herbicides in LA settings, followed by protection of infrastructure. Health and safety considerations were ranked the least important reason for use. One LA stated that whilst health and safety was important there is little evidence to suggest that accidents are caused by weed growth.

Please note for the rank, the lower the number the more important the reason. Please see Appendix 5 Survey methodology for a description of statistical methods used.

All 28 LAs reported that they took steps to minimise and target their use of herbicides. The steps taken to minimise herbicide use are presented in Figure 8 and Table 7. It is evident that the primary steps taken to minimise use were both evaluation of whether there were alternative methods of control available, and also consideration of using the minimum product rate or reducing the area sprayed. Some LAs also cited whether the financial loss, damage or visual effect caused by the weed outweighed the cost of herbicide application as a commonly used criterion while others did not. Other actions such as use of weed assessments or thresholds prior to herbicide application and taking on advice from a professional agronomist adviser were amongst the least commonly used criteria. Other reasons provided included the use of mulch to minimise weed growth and reduce herbicide applications and using volunteer groups to help remove weeds and reduce the need for herbicide use.

Please note for the rank, the lower the number the more commonly used the criteria. Other includes identification and continued roll out of controlled biodiversity areas, use of controlled droplet applicator and reduced frequency of street spraying. Please see Appendix 5 Survey methodology for a description of statistical methods used.

LAs were also presented with a list of factors and asked how strongly they influenced their decision to use herbicides rather than non-herbicide alternatives on a scale (1 equals little influence to 5 equals strong influence). Please see Appendix 5 Survey methodology for a description of the statistical methods used. The mean ratings and percentages of respondents rating each factor as a strong or weak influence are presented in Figure 9 and Table 8.

The respondants stated that the fact that herbicide treatments were more effective than non-chemical alternatives had the strongest influence on choosing to use herbicides. The perceived longer lasting effects of herbicide control, as well as their lower cost, also had a strong influence as did the limited availability of alternative control techniques.

LAs were given the opportunity to provide other factors which influenced their decision making process. Two LAs suggested that budget and manpower constraints were a reason they used herbicides rather than alternatives.

Other factors mentioned by LAs which influenced their decision-making process included budget and manpower constraints

The percentage of respondents giving each rating for each factor are shown above. Please see Appendix 5 Survey methodology for a description of statistical methods used.

Each local authority was asked if they had plans to reduce the amount of herbicide applied in the future and, if so, how they intended to do so. Twenty-four (86 per cent) replied yes, only one replied no and a further three stated they did not know (Figure 10). The main methods LAs intend to implement to reduce the use of herbicides included a continutation and expansion of the reduction strategies already in place (as reported in Figure 8), and mainly focussed on further reduction of the number of applications and the area sprayed, as well as increasing the use of non-chemical control. Several LAs stated they were currently exploring and trialling alternative methods of control and incorporating integrated weed management into future planning projects.

Three of the LAs commented that they had banned or restricted the use of glyphosate on certain surfaces in 2019/20 (during or after our data collection period). One further LA stated that they were currently reviewing their furture use of glyphosate.

Herbicide application operatives, training and record keeping

In 14 LAs, herbicides were applied solely by LA staff; in one LA, applications were applied by a contractor, and in 13 LAs, herbicides were applied by both LA staff and contractors. In relation to training for pesticide operators, 27 LAs (100 per cent) stated that a PA1 (safe handling and application of pesticides) and 25 (93 per cent) stated that a PA6 (safe use of hand held applicators such as knapsacks and hand-held lances) were the basic level of qualification required by their operators. A further 15 (56 per cent) said a PA2 (boom sprayers) was required by some staff to allow them to apply herbicides by mounted boom sprayers. Only three LAs reported that a BASIS qualification was required as a basic level of training for some staff e.g. pesticide store operatives. However, 21 LAs (78 per cent) stated that BASIS qualified staff were used to advise on herbicide use.

Eight of the responding LAs (30 per cent) stated that they kept records of how effective herbicide control measure had been.