Implementation of Wageningen Drift Calculator

The Wageningen Drift Calculator (WDC) is a tool for calculating drift deposition figures for all specific combinations of crop, cultivation-free zone (TVZ) and drift reduction class (DRT). The tool contains the most recent drift figures based on application parameters and crop parameters. This makes it possible to determine – without a specific drift report – which DRT class and cultivation-free zone are required for safe use.

The drift databases underlying the WDC are larger and more recent than the ones currently being used. As a result, the drift deposition figures for the various crops have also changed. In addition, the drift deposition figures from the WDC – especially for downward-sprayed crops – are more specific because parameters such as crop stage and position of the last nozzle in relation to the crop are also included. The WDC is therefore more realistic than the current method.

Due to the distinction between a 'bare ground' situation and a 'non-bare ground' situation (limit at 20 cm crop height), it has been decided that if the crop stage exceeds this height limit within the requested use, the highest drift deposition value for both situations must be used.

The maximum crop-free zone and the maximum acceptable drift reduction class (DRT 90) for downward spraying remain as specified in the Evaluation Manual. Consultation about this is currently taking place, and possible changes will be communicated promptly.

Starting date

The use of the WDC has consequences for dossiers for a national application. To ensure fairness, the WDC has therefore been implemented for new applications and not for pending applications. However, the WDC can be used optionally for pending applications. Applicants will have the usual six months to prepare new national applications for using the WDC. The Board has decided on the following transitional arrangement:

  • From 01-01-2022, the WDC will be mandatory for new national application dossiers;
  • From 01-08-2021, the WDC will be optional for national application dossiers, for both new and pending applications.

In addition, the Board has decided to phase out individual techniques in the legal instructions for use (WG); for all plant protection uses, a DRT class must now be included in the WG, if necessary in combination with a cultivation-free zone. Therefore, as of 01-01-2022, individual techniques will no longer be allowed on the labels to mitigate the risk for non-target arthropods.

Scope of the WDC

The WDC can only be used for spraying by professionals on crops that fall under the scope of the Environmental Management Activities Decree (AB) and, if the techniques are classified in DRT classes, in national applications.

This includes:

Arable crops (downward spraying)

Fruit trees and avenue trees (upward and lateral spraying)

The implementation of the WDC has no consequences for the procedures for crops/uses that do not fall under the Activities Decree and manual/non-professional use.

Impact on harmonisation of drift deposition figures

The introduction of the WDC has an impact on the method whereby the risk assessment of drift-related environmental aspects of the Core can be used for national applications. This impact is currently being reviewed and will be disclosed in the near future.

Evaluation Manual

The Evaluation Manual (relevant chapters Chapter 6 Aquatic behaviour and Chapter 7 Terrestrial non-target arthropods and non-target plants) is being updated due to the implementation of the WDC and will be published as soon as possible. The current external DRT work instruction will also be adapted accordingly. Another change to the assessment framework, which does not result directly from the implementation of the WDC, but will take place simultaneously, is the starting situation for crops to which the drift deposition values for large fruit apply, but which are not subject to the preconditions in the AB (as referred to in Art 3.80.3) for apples, pears, and other pome and seed fruit: woody berries, hops, nuts and other fruits. We will publish these changes as soon as they have been implemented.