Spraying with minimal spray drift (herbicides, Phytophthora infestans)

Clean surface water is important. Reducing the use of pesticides along ditches that carry water limits emission to surface water. Drift-reducing nozzles, mandatory or not when using a specific pesticide, help to reduce spray drift. Other techniques can also minimize spray drift, enhance the efficacy and thus reduce the dosage.
Lessons:
• Choose the right spraying nozzle. In the Netherlands, within 14 metres from ditches drift-reducing nozzles must be used. Depending on the pesticide, the reduction needs to be 50, 75 or 90 %.
• A high pressure results in smaller drops, which cause more spray drift. The height of the spray boom must not exceed 50 cm above the crop.
• Avoid spraying at wind speeds of 5 m/s or more and at driving speeds of 6 km/h or more
• The weather conditions before spraying, at spraying and after spraying are important, especially for herbicides. A decision support system that predicts the weather conditions (GEWIS, Dutch) can help to find the right spraying time and gives advice on whether reduction of the dose is possible.
• Using low drift nozzles can diminish the effect of the pesticide, because the leaf cover is less. The use of a surfactant can compensate for this.

The leaflet is produced and distributed in the project ‘Telen met toekomst’ (Growing with Future). In this project farmers discuss in study groups and generate measures that can help to reduce emission to the environment. Applied Plant Research (WUR) and the independent extension service take care of knowledge exchange and collection.
Information is given on how the farmer can reduce spray drift. In a short interview the farmer or producer gives his view on the measures. Links are also provided to a site with a list of drift-reducing nozzles and to the project.