Comparison of trapped western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae) to yellow and blue sticky traps in three different heights on two greenhouse rose cultivars

Western flower thrips, Frankliniella occidentalis (Pergande), an important pest in rose greenhouses, has several generations per year, and in addition to direct feeding damage to rose flowers it also transmits tospoviruses. Because of resistance to insecticides, alternative strategies are needed to manage this pest, including trapping. In this study, trapping by sticky traps of two different colours (blue and yellow) was experimented at three different heights (at canopy level, and 20 cm above and below canopy level) on two rose cultivars (Red one and Avalanche). The numbers of trapped thrips were counted after five days. The number on the blue sticky traps, regardless of their height of placement and type of cultivar, was significantly higher than that on the yellow traps. Number of thrips on blue traps at 20 cm above the canopy was significantly higher than on blue traps at the other levels in both cultivars. In contrast, the number of thrips that were trapped in yellow sticky tarps in various heights as well as cultivars was not significantly different.