The UK Pesticide Load Indicator (PLI)

THE PPDB
The UK Pesticide Load Indicator (PLI)

About the UK PLI

The PPDB has been used to support the UK PLI. The PLI supports policymakers and other stakeholders understand changing pressures on the environment associated with pesticide use. This includes supporting a national target to reduce pesticide load by at least 10% by 2030, using 2018 as a baseline year (as outlined in the UK Pesticides National Action Plan 2025.

It consists of 20 load metrics: 4 environmental fate metrics (covering behaviour in the environment such as persistence and mobility) and 16 ecotoxicity metrics (covering toxicity to non-target wildlife species). These metrics are calculated based on standardised measures compiled as part of the PPDB and BPDB. The per kilogram value of the indicator can then be combined with estimates of the mass of application (based on the UK Pesticide Usage Survey (PUS) to examine patterns in load across space and time. Further details can be found in the publications below.

A farm level calculation of the PLI is also available in the Farmland Ecosystem Assessment Support Tool (FEAST). This software application allows users to calculate the PLI at the field and farm level. The results can be used to identify those substances which contribute the most to pesticide load and thus help target action to reduce that load (and thus contribute to achieving the national target). The results can also be plotted spatially on maps and overlaid with other assessments (such as habitat suitability for key farmland wildlife species).

Publications

Tzilivakis, J., Lewis, K.A., Kennedy, M.C., Ridley, L. and Garthwaite, D.G. (2026) The UK pesticide load indicator: development toward a policy tool. Journal of Environmental Science and Health, Part B, 61(1), 1-18. DOI: 10.1080/03601234.2025.2610127
Lewis, K.A. and Tzilivakis, J. (2025) Pesticide environmental indicators and the need to minimise uncertainty. Environmental Scientist, 35.2, 68-75. URL: https://www.the-ies.org/resources/are-we-measuring-what-matters
Kennedy, M., Garthwaite, D., Ridley, L. and Tzilivakis, J. (2024) UK Pesticide Load Indicator. Phase 5 Update Report. Prepared for the Department for Environment, Food and Rural Affairs (Defra) for Project PC0122, by FERA Science Ltd and the Agriculture and Environment Research Unit (AERU), University of Hertfordshire, UK. URL: https://sciencesearch.defra.gov.uk/ProjectDetails?ProjectId=21394
Rainford, J, Tzilivakis, J., Garthwaite, D., Jones, G. and Lewis, K.A. (2023) Finalising a Pesticide Load Indicator for the UK: Phase 4 Report. Prepared for the Department for Environment, Food and Rural Affairs (Defra), UK, for project PC0116, by FERA Science Ltd and the Agriculture and Environment Research Unit (AERU), University of Hertfordshire, UK. URL: https://randd.defra.gov.uk/ProjectDetails?ProjectId=21074
Lewis, K.A., Rainford, J., Tzilivakis, J. and Garthwaite, D. (2021) Application of the Danish Pesticide Load Indicator to UK arable agriculture. Journal of Environmental Quality, 50(5), 1110-1122. DOI: 10.1002/jeq2.20262

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