Wind tunnel measurements and model predictions for estimating spray drift reduction under field conditions

It was concluded that spray drift reduction is dependent on distance downwind, but that wind tunnel measurements can be used to estimate this at least up to 20 m downwind. Improvements to the wind tunnel protocol were identified, which will need to take account of how the data will be used in the regulatory process before implementing. Further discussions are needed to harmonise methods for determining spray drift reduction across EU member states, but this approach of mapping the wind tunnel data onto field data is one that should be possible with other methods.