Limonene: attractant kairomone for white pine cone beetles (Coleoptera: Scolytidae) in an eastern white pine seed orchard in western North Carolina

I report on the attraction of the white pine cone beetle, Conophthoru.s coniperda (Schwarz) (Coleoptera: Scolytidae), to traps baited with the host monoterpene limonene in western North Carolina. Both (+)- and (-)-limonene attracted male and female cone beetles to Japanese beetle traps in an eastern white pine, Pinus strobus L., seed orchard near Murphy, NC. Catches of cone beetles were directly proportional to the release rate of (-)-limonene; (+)-limonene was not tested for dose response. Attraction of cone beetles to the pheromone (+/-)-trans-pityol was increased significantly by both enantiomers of limonene. In all experiments, catches of C. coniperda were strongly male biased with no treatment effect on sex ratio. (- )-Limonene had no effect on trap catches of the predator Enoclerus nigripes (Say) to pityol, whereas (+)-limonene interrupted the attraction of E. nigripes to traps baited with pityol. Of six monoterpenes commonly found in white pine cones, only (-)-alpha-pinene elicited attraction of E. nigripes to Japanese beetle traps.