Evaluation of sticky trap colour for thrips (Thysanoptera) monitoring in pea crops (Pisum sativum L.)

We compared the effectiveness of three different trap colours (blue, yellow and white) to identify the optimal trap colour for the monitoring of the thrips Frankliniella intonsa, Thrips tabaci, Thrips fuscipennis and Aeolothrips intermedius in the three pea cultivars, namely Polar, Izolda and Tarchalska. The number of captured thrips specimens was significantly affected by trap colour, pea cultivar and interaction between these factors. The two most attractive trap base colours for thrips were blue (peak at 450 nm) and yellow (peak at 550 nm). Irrespective of the pea cultivar, most F. intonsa were captured on the blue and yellow traps. Blue traps were the most attractive to T. fuscipennis and T. tabaci, followed by yellow and white ones, and yellow traps were most attractive to A. intermedius. More thrips were caught on the traps located in the plots with cultivars characterised by a longer growing season Tarchalska and Izolda, which were inhabited by large numbers of thrips. There was a significant interaction effect between trap colour and pea cultivar on the number of caught F. intonsa and T. fuscipennis in both years and for T. tabaci in 2010. Overall, among the tested trap colours, blue traps were the most effective ones for monitoring thrips in pea fields and could be used as an early detection tool. Yellow traps may be risky because they reduce population densities of the predaceous A. intermedius in pea fields, thus leading to an increase in pest numbers.