The distribution of Western flower thrips trapped on yellow cylinder

Abstract

Abstract The Western flower thrips (WFT), Frankliniella occidentalis, is a very important pest of many crops worldwide and a vector of viral pathogens. Monitoring WFT in open fields using attractive colored traps mounted on wind vane indicated that the vast majority of trapped thrips were on the leeward side of the traps. In this study, we determined the distribution of trapped WFT on cylindrical yellow traps under controlled conditions in a wind tunnel (24 ± 1°C, 70 ± 4% RH, airflow speeds 0.19 m sec− 1). In each experiment, we released 150–250 WFT females, either upwind or downwind of the cylindrical yellow sticky trap. Each experiment lasted six hours. Overall, 79%±14 of the released WFT females flew actively and 59%±15 of those that flew were trapped. The vast majority of the thrips were trapped on leeward side of the cylindrical yellow traps. Of the WFT females released downwind of the trap, 93%±3 (N = 6) were trapped on the leeward side, while of those released upwind of the trap, 81%±8 (N = 7) were trapped on the leeward side. A behavioral-biomechanical model simulating WFT flight towards the attractive yellow cylinders predicted that, as long as airflow speed is below the WFT flight speed, 71–84% of the WFT will be trapped on the leeward side. The results of this study are in agreement with the trapping distributions of WFT recorded in field studies. The results also suggest that, when airflow speed is below the WFT flight speed, most WFT approach visually attractive traps by actively flying upwind.