Today’s invention removes the need for crop spraying aircraft.
Instead, wind turbines placed on the edges of fields would each be fitted with a trough at the base.
When the wind is blowing in the right direction across the fields, the turbine turns in the usual way.
As each blade passes through the trough, it scrapes out a small amount of eg powdered insecticide and this is then dispersed, by the turbulent downstream flow, across the crops.
The particulate matter would be retained within the turbulent boundary layer, so that its distribution could be made reasonably uniform.