Factors affecting pheromone-baited trap capture of male Coleophora deauratella, an invasive pest of clover in Canada.

Coleophora deauratella Leinig and Zeller (Lepidoptera: Coleophoridae) is an invasive pest of red clover, Trifolium pratense L. (Fabeles: Fabaceae), grown for seed in Canada. A pheromone-based monitoring program to determine the presence and seasonal activity of adult C. deauratella would be a valuable tool for growers because larvae are difficult to sample due to their internal feeding behavior. We conducted field experiments to evaluate several pheromone-baited trap characteristics, including pheromone lure substrate, trap type, trap color, lure longevity, trap height, and field position. The type of substrate that pheromone was released from and lure age did not affect trap capture of male C. deauratella. Moth capture in nonsaturating green Unitraps was significantly higher than Diamond or Wing traps when inspected at 2-wk intervals. Multi-colored Unitraps caught significantly more male C. deauratella than Diamond, and Wing traps when inspected at weekly intervals. Trap color did not influence C. deauratella capture, but by-catch of bumblebees, Bombus spp., was greatest in yellow and white colored Unitraps. Traps placed 35 cm above the soil surface captured more male C. deauratella than those placed at 1 m above or at ground level regardless of trap position within the field. Green Unitraps baited with either gray or red rubber septa lures placed 35 cm above the soil surface and 5 m from the field edge should be used to monitor C. deauratella. These characteristics optimize pheromone-baited trap performance and reduce by-catch of beneficial insects, and should be incorporated into a C. deauratella pheromone-monitoring program.