Aerial spraying apparatus includes two sets of nozzles located at spaced locations on an aircraft. Each nozzle has an electrode associated with it to induce a charge on the cloud of droplets issuing from the nozzle. A high potential is maintained on each electrode by a power pack that induces an equal and opposite potential on the electrodes of each set. By virtue of the opposed polarity of the electrodes, the aircraft is maintained at a neutral potential. To prevent a potential being imposed due to spray being deposited on the electrodes, a pair of corona needles are provided to establish a leakage current and maintain the electrodes at the required potential. This prevents the system becoming imbalanced and a potential being established on the aircraft.