An electric dipolar screen with oppositely polarized insulators for excluding whiteflies from greenhouses

A new electrostatic insect-proof screen (electric dipolar screen) was developed using insulated conductor wire. Copper conductor wire is encased in a flexible transparent vinyl insulator sleeve and charged with an electrostatic voltage generator. Paired insulated conductor wires were placed in parallel with 5 mm of separation and oppositely charged with 15 kV DC using separate electrostatic voltage generators. A negatively charged conductor wire polarizes the insulator negatively at the outer surface and positively on the conductor side, and a positively charged conductor wire polarizes vice versa. A pair of insulated conductor wires with opposite surface charges was used as an electric dipole. An electric dipole creates an electrostatic force from positive to negative poles. This force was harnessed to trap whiteflies entering greenhouses. Dipolar wires were attached in parallel to a frame to construct an electric dipolar screen that could be fitted to greenhouse windows. The screen prevented adult whiteflies from passing through spaces (up to 30 mm) between the wires of the screen, and tomato plants inside remained free of whiteflies throughout the entire 3-week experiment, in contrast to heavy infestation of all plants in the uncharged area. Thus, the electric dipolar screen is a promising tool to physically exclude flying whiteflies from greenhouses.