We have developed an electrostatic pesticide spraying system for low-concentration, high-volume applications to reduce vegetable production costs through savings in agricultural chemical usage and working hours for pest control. The electrostatic spray charging device (ESCD) has an outer annular induction charging electrode around a hydraulic nozzle with a high flow rate. The charge-to-mass ratio of spray droplets was -0.30 to -0.45 mC/kg at +4 kV, using a hollow-cone nozzle with a high flow rate delivering 1.0 to 2.6 L/min. No discharge or electric leakage occurred from the electrode. Using this device, we developed two types of sprayers. One type was an electrostatic boom-type sprayer for cabbage vegetables. Field tests showed that this boom-type sprayer reduced the amount of required pesticide application by 30% as compared to the conventional method.
The other type was a spraying robot for greenhouse melons. There was no significant difference in the control of insect pests between robot spraying and the conventional manual spraying method. The effective field capacity of the robot was 3.8 a/h.