Effect of deterrent light-emitting diode (LED) qualities on the visual behaviour of the greenhouse whitefly Trialeurodes vaporariorum

Abstract: Visual traps, such as yellow sticky traps, are widely used for monitoring of the
greenhouse whitefly Trialeurodes vaporariorum. Understanding the visual orientation of
whiteflies can significantly contribute to implementation of visual traps not only for their
monitoring, but for successful mass trapping, leading, thus, to the development of new crop
protection strategies. Incorporation of visual cues with a deterring effect on whiteflies can result on their repellence from the crop, increasing, hence, the possibility of them landing on the traps. Based on existing findings on the effect of different light colours on whitefly visual behaviour, this study investigated the effect of deterrent light-emitting-diode (LED) colours as a repellent tool against greenhouse whiteflies. Different LED wavelengths, intensities and exposure periods were evaluated in no-choice assays, under controlled conditions. The results revealed that LED intensity and exposure period were positively correlated to whitefly dispersal and wavelengths of blue and blue + UV showed up to 21 times higher deterrent effect than in the control (no LEDs). These findings expand our knowledge on whitefly visual behavior and contribute to the development of new mass trapping strategies in IPM.