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

Abstract

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.

A Promising Physical Pest-Control System Demonstrated in a Greenhouse Equipped With Simple Electrostatic Devices That Excluded All Insect Pests: A Review

“…A double-charged dipolar-type screen is easily constructed by linking the ICWs alternately to negative and positive voltage generators (Nonomura et al, 2014a;Matsuda et al, 2012), forming an electric field between the oppositely charged conductor wires. We know that some electrons are present in air.…”

“…In a greenhouse in which the side windows were equipped with S-screens, the problem of pest entry through the greenhouse door remains. To solve this problem, an anteroom was created to eliminate pests ( Figure 3B) (Nonomura et al, 2014a). Ground net-free D-screens were installed in the anteroom in an attempt to create an ideal greenhouse that excluded all pests.…”

“…The concept of an anteroom for eliminating pests combines the functions of electric field screens with regulation of the airflow in the room (Figure 4). This room was designed to generate airflow mechanically when the doors were opened, and to direct the airflow through the electric field screen (Nonomura et al, 2014a). To evaluate the effectiveness of this system, we blew air into the anteroom when the door was opened and simultaneously released whiteflies to examine the direction of the airflow and the capture of insects by the electric field screens ( Figure 4A).…”

Novel electrostatic devices for managing biotic and abiotic nuisances in environments

“…The first application is the installation of the electric field screens to a greenhouse to keep the inside spore-free and pest free. 58 For this purpose, two types of the screen, SD-screen ( Figure 1C) and DDscreen ( Figure 1D) are used to repel the insects reaching the screen net installed to the lateral windows and to directly capture the insects through the entrance door of the greenhouse, respectively. Figure 2A shows a A-shaped greenhouse whose lateral windows are furnished with SD-screens attached to the window frame.…”

“…Our electrostatic method was effective at keeping the greenhouse pest-free throughout the entire period of tomato cultivation. 58 Incidentally, roof windows are not furnished with the screens because of the structural difficulty of doing so, and these remained closed during the experiment. Extractor fans are fitted on the front wall of the greenhouse.…”