Effect of Trap Color, Height, and Orientation on the Capture of Yellow and Stick Tea Thrips (Thysanoptera: Thripidae) and Nontarget Insects in Tea Gardens

Abstract

Two thrips species-the yellow tea thrips ( Scirtothrips dorsalis Hood) and the stick tea thrips ( Dendrothrips minowai Priesner)-are serious pests affecting tea plants in southern China. Although the stick tea thrips is primarily restricted to southern China, the yellow tea thrips is gradually proliferating worldwide. Colored sticky card traps may be useful for monitoring and capturing these species, but a systematic analysis has not been conducted to identify the most effective trap color, height, and orientation. We performed indoor experiments using an orthogonal experimental design, as well as field tests in tea gardens, to identify the color most attractive to the two thrips species. Field tests were then conducted using color-optimized traps-lawngreen (RGB: 124, 252, 0) for yellow thrips and lime (RGB: 0, 255, 0) for stick tea thrips-to determine the most effective trap height and orientation. The greatest numbers of both yellow and stick tea thrips were captured on traps positioned 0-20 cm above the tea canopy in an east-west orientation. We also evaluated the performance of the color-optimized sticky card traps compared with commercially available yellow ones. Significantly more yellow and stick tea thrips and fewer natural enemies were captured on the color-optimized traps than on commercial ones. Although additional research is needed to explain the responses of the two different species and to increase trap effectiveness, our findings should assist in the control of these harmful insects.

Keywords: color; height; orientation; sticky card trap; thrips.