Dose and enantiospecific responses of white pine cone beetles, Conophthorus coniperda, to alpha-Pinene in an eastern white pine seed orchard.

The white pine cone beetle, Conophthorus coniperda, exhibited dose and enantiospecific responses to alpha-pinene in stands of mature eastern white pine, Pinus strobus, in a seed orchard near Murphy, North Carolina, USA. (-)-alpha-Pinene significantly increased catches of cone beetles to traps baited with (+/-)-trans-pityol. (+)-alpha-Pinene did not increase catches of beetles to pityol-baited traps and interrupted the response of beetles to traps baited with (+/-)-trans-pityol and (-)-alpha-pinene. Maximal attraction of cone beetles to pityol-baited traps was obtained with lures releasing (-)-alpha-pinene at a rate of 103 mg/day at 23 degrees C. Lures releasing (-)-alpha-pinene at rates lower or higher than 103 mg/day resulted in reduced catches to traps baited with (+/-)-trans-pityol. The sex ratio in all catches was heavily male biased. Attraction of the clerid predator, Thanasimus dubius, to traps baited with (+/-)-trans-pityol increased significantly with the presence of alpha-pinene, irrespective of enantiomeric composition. Maximal attraction of T. dubius to pityol-baited traps occurred with devices releasing (-)-alpha-pinene at the highest rate tested, 579 mg/d at 23 degrees C, a sub optimal rate for cone beetles.