Phototactic response of Frankliniella occidentalis to sticky traps with blue light emitting diodes in herb and Alstroemeria greenhouses

Nina Svae Johansen,Torfinn Torp,Knut Asbjørn Solhaug

doi:10.1016/j.cropro.2018.08.023

Nina Svae Johansen, Torfinn Torp + Show 1 more

Open Access

https://doi.org/10.1016/j.cropro.2018.08.023

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Abstract

Blue and yellow sticky traps equipped with blue light emitting diodes (LEDs) were evaluated for their attractiveness to the western flower thrips (Frankliniella occidentalis Pergande) and compared to similar traps without light in two greenhouses with commercial production of either mixed herbs or Alstroemeria cut flowers. Blue traps were more attractive to F. occidentalis than the yellow traps in both crops, regardless of whether they were equipped with light or not. In herbs, the blue light equipped traps caught 1.7 to 2.5 times more thrips compared to blue traps without light, and 1.7 to 3.0 times more thrips than yellow traps with light. Blue light on both blue and yellow traps increased thrips catches in one out of two experiments in Alstroemeria. The blue light equipped traps caught 3.4 and 4.0 times more thrips than blue traps without light in coloured and white Alstroemeria cultivars, respectively, whereas yellow light equipped traps increased thrips catches 4.5 times compared to yellow traps without light in both coloured and white cultivars. The yellow light equipped traps caught, however, only equal to or only slightly more thrips than blue traps without light, and caught fewer thrips than the light equipped blue traps. The relative trapping efficiency of the different combinations of trap colour and light varied with experiment, crop and Alstroemeria cultivars. This suggests that factors other than merely the addition of light influenced the thrips' phototactic response to the traps. Such factors could be differences in the relative strength of the competition between attractive signals from traps and plants between the two crops and Alstroemeria cultivars, thrips density, seasonal lighting conditions or different pest management strategies and other operational procedures in the greenhouses. The light from the traps did not increase the thrips population on the plants below the traps. The implications of the results for thrips control and suggestions for further studies are discussed.

Highlights

The western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is a major pest in a wide range of greenhouse crops (Lewis, 1997; Kirk and Terry, 2003), and can cause considerable direct damage through feeding, oviposition scars and virus transmission (EPPO/CABI, 1997)
The preference for blue over yellow traps is consistent with several earlier greenhouse studies (Brødsgaard, 1989; Gillespie and Vernon, 1990; Vernon and Gillespie, 1990a; Vernon and Gillespie, 1990b; Roditakis et al, 2001; Roth et al, 2016)
According to Vernon and Gillespie (1990a), thrips catches on yellow traps tend to be less predictable than catches on blue traps

Summary

Introduction

The western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is a major pest in a wide range of greenhouse crops (Lewis, 1997; Kirk and Terry, 2003), and can cause considerable direct damage through feeding, oviposition scars and virus transmission (EPPO/CABI, 1997). Blue and yellow reflected light is attractive to F. occidentalis, and elicits a positive phototactic response towards the coloured object (Johansen et al, 2011b). This phenomenon is utilized in the use of blue and yellow sticky traps for monitoring of F. occidentalis in greenhouses (Yudin et al, 1987; Gillespie and Vernon, 1990; Roth et al, 2016). The capacity of these traps is, too low for practical and cost-effective mass trapping (Vernon and Gillespie, 1995; Broughton et al, 2015). One way to increase trap catches is to strengthen the thrips’ positive phototactic response by making the visual signal from the traps more attractive

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