Blue and UV light-emitting diodes (LEDs) disturb the greenhouse whitefly (Trialeurodes vaporariorum) from its host

Abstract

Push–pull strategy is a well-known and widely used technique for integrated pest management, leading to the reduction of insecticides. This strategy involves the use of mostly visual and chemical stimuli to repel pests from a valuable crop (push) and attract them to an appealing target, e.g., a trap, (pull). Based on former results, this study explored the effect of light-emitting diodes (LEDs) as repelling factors of whiteflies (push). Wavelengths of blue and ultraviolet (UV) were investigated in different light intensities and exposure times in no-choice experiments, under controlled conditions. Whiteflies were exposed directly to LEDs on the underside of tomato leaves and number of repelled insects was counted. The results showed that light intensity and insect repellency were positively related. Insect repellency increased up to tenfold with longer light exposure period. Wavelength of blue and combination of blue + UV repelled more than 87% of whiteflies in light conditions. In darkness, results were only slightly different. The results reveal the property of blue light to repel whiteflies from its host and that addition of UV to blue enhances this effect. They further demonstrate that whitefly vision is dependent on wavelength, light intensity and exposure period. The contribution of the results on understanding the visual behavior of whiteflies and their possible implementation on pest control strategies is discussed.