Crop interception standard approach and refinements: pesticide registration in Great Britain and Northern Ireland

When you are applying for registration of a pesticide in Great Britain and Northern Ireland, you must consider crop interception. Crop interception is the % of the applied pesticide which is intercepted by the crop and does not reach the soil surface. Consider crop interception when determining the PECsoil, PECsw drainflow and PECgw.

Use crop interception values from the EFSA DegT50 guidance. If crop interception values are not available for your crop, select an appropriate surrogate crop based on crop morphology at the relevant growth stages. Note that these values are appropriate for spray applications only. For other types of application, such as granules, assume 0% interception in a first-tier assessment. Refinement of crop interception for these other types of application will only be possible based on submission of data or further information.

If you require further guidance please contact HSE.

Standard crop interception approach

Use the worst-case crop interception for the proposed use. For single application GAPs with wide application patterns, that is usually the growth stage that has the lowest % crop interception and the maximum amount of pesticide reaching the soil. Note that for most crops applications to earlier growth stages results in lower crop interception, but for some crops the level of interception also reduces during the final senescence and ripening stages. Note also that groundwater and surface water exposure via drainflow are sensitive to application timing. Therefore, for these compartments, later applications with higher levels of crop interception can still be more conservative.  You may need to provide exposure assessments for multiple application dates to support your use pattern.

For multiple application GAPs with wide application patterns, use the worst-case crop interception for each application at the first tier. Provide a clear justification if you intend to use higher crop interception values for later applications made to later growth stages.

If an acceptable risk cannot be demonstrated based on the worst-case crop interception you may be able to restrict application to later growth stages only.

Use of the crop interception values are explained within the relevant sections in:

Crop interception for basal applications to orchards

If you are applying for authorisation of products containing contact herbicides for use around the base of tress in orchards use 0% crop interception.

Banded applications

For banded applications, assess the level of soil exposure within the treated band based on appropriate crop interception values for the treated crop area.  For groundwater and surface water via drainflow only, the exposure assessment can be refined to account for the untreated area. The proportion of treated area must be stated on the product label. This approach would be acceptable to assess banded applications around the base of trees in orchards.

Label phrase to use: ‘To protect groundwater/aquatic organisms/terrestrial organisms (delete as appropriate) this product must only be applied to the area immediately around trees, and the total surface area treated must be equal to or less than X % of the total area’.

Example: Product GAP is 50g a.s. /ha. Only 50% of land is treated.

  • PECgw and PECsw drainflow: Exposure assessments based on 25g a.s./ha.
  • PECsoil, PECsw spraydrift and PECair: Exposure assessment should be based on 50 g a.s./ha,


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Updated 2021-08-10