Prevention of Whitefly Entry from a Greenhouse Entrance by Furnishing an Airflow-Oriented Pre-Entrance Room Guarded with Electric Field Screens

Two types of an electric field screen were used to exclude whiteflies from a greenhouse. Singly charged dipolar electric field screen had insulated conductor iron wires arrayed in parallel (ICW-layer), two earthed metal nets on both sides of the ICW-layer, and a direct current voltage generator. Screens were attached to the lateral windows of the greenhouse to repel whiteflies that approached the nets. To electrostatically guard the greenhouse entrance, doubly charged dipolar electric field screens (DD-screens) were used to capture whiteflies entering through the door. The ICWs, oppositely charged with equal voltages, were arrayed one after the other, and an insulator board or net was placed on one side of the ICW-layer. ICWs captured whiteflies entering an electric field of DD-screens. A small pre-entrance room was constructed at the entrance area, and three DD-screens (with yellow and gray board or gray net) were installed in the pre-entrance room taking into consideration the airflow inside the room, as most whiteflies were brought in by the air when the door was opened. Two DD-screens with the board were useful for directing the wind toward the wall into which the netted DD-screen was integrated. Insects were eliminated by this screen, and the pest-free air was circulated inside the greenhouse. The yellow-boarded DD-screen was highly attractive because of the photo-selective movement of the whiteflies and was effective for trapping the whiteflies when there was no wind. Our electrostatic method is effective at keeping the greenhouse pest-free throughout the entire period of tomato cultivation.