Efficacy evaluations and guidelines

This guidance is to help you complete the efficacy section of a pesticide application.

What efficacy is

Efficacy can be defined as determining the effectiveness of a substance, including identifying the appropriate dose and mode of action, and identifying any adverse or unintended negative impacts. 

In regulatory assessments, the relevant claims of the proposed product must be supported by data. These data are generated from appropriately conducted trials, following relevant guidance and are provided to address regulatory requirements. 

Efficacy assessments for plant protection products (PPP)

HSE’s Efficacy Team considers:

  • whether the claims made on the product labels are supported by data
  • the relevance of the proposed uses to Great Britain (GB) and Northern Ireland (NI) effectiveness, risk to the crop and resistance issues
  • whether there is a demonstrated benefit (to the crops or in non-crop situations) and put into context with any identified adverse impacts (for example damage caused to the crop)
  • the directions on the label to ensure they are appropriate to the use of the product - this contributes to using the product in a targeted, responsible manner optimising its' use as part of integrated control programmes with other measures, but ensuring it is the minimum required

Data requirements and accompanying guidance

Data supporting GB and NI authorisations for a PPP should follow the appropriate guidance (EPPO, see below) and address the relevant data requirements for the active substance and the formulated product.

European Plant Protection Organisation (EPPO)

EPPO is an international organisation responsible for cooperation and harmonisation in plant health and protection within the European and Mediterranean region. 

HSE provides expertise on a number of PPP related panels and expert working groups.

EPPO produce standards on how to approach efficacy evaluations, which are recognised in regulatory regimes, including GB, NI, EU, FAO and OECD. These range from general standards addressing regulatory data requirements (such as Phytotoxicity (PP 1/135)) to standards describing the conduct of individual efficacy trials (such as aphids on cereals (PP 1/020)).  

 EPPO website.

Data generated outside GB and NI

You may use data generated outside GB and NI to support GB and NI products, provided there is an appropriate case for relevance to GB and NI agronomic conditions.

EPPO PP 1/278 'Principles of zonal data production and evaluation' provides a comprehensive overview of the relevant issues when generating and using regionally based data.

Further information is provided in Efficacy Guideline 106.

In some situations, where guidance is not harmonized via EPPO or in a limited number of GB and NI specific situations, additional GB and NI guidance is relevant and must be followed (for example, for resistance management).

GB and NI additional guidance

Refer to the guidance below when applying for uses in GB and NI.

Included are guides and information on:

  • crops and situations
  • details of relevant targets
  • resistance management and labelling

This may help in trials planning, summarising data and supporting GB and NI label claims.

Please note that efficacy data generated in other countries may support GB and NI authorisations, provided there is an appropriate case for relevance to GB and NI agronomic conditions. EPPO PP 1/278 provides a overview of the relevant issues on generating and using regional data packages.

Go to EPPO PP 1/278 (on the EPPO website).

In future, a range of comprehensive crop guides will be produced.

General guidance on generating data and submitting applications

Efficacy Guideline:

Application or Situation Specific Guidelines

Crop safety guidelines

303 - Effects on Non-Target Crops of Highly Active Herbicides – Including Mixtures and Sequences
Revised July 2020

Crop specific guidelines

Chemical and control specific guidelines: resistance management and tank mixtures/sequences

Other efficacy related guidance

Back to top

Is this page useful?

Updated 2024-08-13