Light emitting diode(LED)‐based trapping of the greenhouse whitefly (Trialeurodes vaporariorum)

Abstract

Visual traps like yellow sticky card traps are used for monitoring and control of the greenhouse whitefly (Trialeurodes vaporariorum). However, reflected intensity (brightness) and hence, attractiveness depend on the ambient light conditions, and the colour (wavelength) might not fit with the sensitivity of whitefly photoreceptors. The use of light emitting diodes (LEDs) is a promising approach to increase the attractiveness, specificity and adaptability of visual traps. We constructed LED‐based visual traps equipped with blue and green high‐power LEDs and ultraviolet (UV) standard LEDs according to the putative spectral sensitivities of the insects' photoreceptors. In a series of small‐scale choice and no‐choice recapture experiments, the factors time of day as well as light intensity and light quality (colour) of LED traps were studied in terms of attractiveness compared to yellow traps without LEDs. Green LED traps (517 nm peak wavelength) were comparably attractive in no‐choice experiments but clearly preferred over yellow traps in all choice experiments. The time of day had a clear effect on the flight activity of the whiteflies and thereby on the trapping success. Blue LEDs (474 nm) suppressed the attractiveness of the light traps when combined with green LEDs suggesting that a yet undetected photoreceptor, sensitive for blue light, and an inhibiting interaction with the green receptor, might exist in T. vaporariorum. In choice experiments between LED traps emitting green light only or in combination with UV (368 nm), the green‐UV combination was preferred. In no‐choice night‐time experiments, UV LEDs considerably increased whitefly flight activity and efficacy of trapping. Most likely, the reason for the modifying effect of UV is the stimulating influence on flight activity. In conclusion, it seems that the use of green LEDs alone or in combination with UV LEDs could be an innovative option for improving attractiveness of visual traps.

Assessing the efficiency of UV LEDs as light sources for sampling the diversity of macro-moths (Lepidoptera)

“…America (Cohnstaedt et al, 2008), greenhouse whitefl ies in Germany (Stukenberg et al, 2015) and aquatic macroinvertebrates in South Africa (Price & Baker, 2016) and New Zealand (Green et al, 2012). In the last mentioned paper, traps with different light sources were tested, including 8 W actinic fl uorescent tubes and approximately 2 W UV/black light (18 LEDs, 395 nm) LEDs.…”

A Greenhouse Test to Explore and Evaluate Light-Emitting Diode (LED) Insect Traps in the Monitoring and Control of Trialeurodes vaporariorum

“…Furthermore, their selective wavelength and intensity enable them to be specifically designed for target pests, reducing harm to beneficial and neutral insects to some extent. Some studies have shown that LED lights served as attractants [11][12][13][14][15] and increased the trapping efficacy of many insects, including greenhouse whiteflies, tobacco whiteflies, sweet potato whiteflies, thrips, and fungus gnats. However, most studies have been laboratory or confined cage studies, and field studies are still quite limited [16][17][18][19].…”

“…Regarding attractive light sources, many aphids and greenhouse whiteflies are attracted to targets that reflect or transmit light in the green-yellow range of the spectrum (520-610 nm), with yellow being the most attractive [8,21,22]. Many experiments with monochromatic lights have shown that adult insects have a peak response to green lights between 520-560 nm [14,23,24]. This shift in visual color attractiveness can be explained by the "opponent mechanism".…”

“…UV light was attractive to the greenhouse whitefly, especially in the dark, but it was less attractive than the green-yellow spectrum [8,13,16]. In a choice cage test, adult greenhouse whiteflies showed a preference for the UV-green LED complex over the green LED alone [14]. Most previous cage studies of LED traps used green and UV LEDs in their tests [13,14,16,17,19].…”

“…In a choice cage test, adult greenhouse whiteflies showed a preference for the UV-green LED complex over the green LED alone [14]. Most previous cage studies of LED traps used green and UV LEDs in their tests [13,14,16,17,19]. The most sensitive behavioral spectrum is not always the most sensitive light receptor spectrum [25]; it is the integration of visual stimuli inputs in the central nervous system that results in the peculiar phototactic response exhibited by the species [8].…”