Electrophysiological and Behavioural Responses O F Tomzcus Pznzperda and Tomzcus M N O R (coleoptera: Scolytidae) to Non-host Leaf and Bark Volatiles

The Canadian Entomologist 32: 965 981 (2000) Leaf and bark volatiles from non-host birches, Betula pendula Roth. and Betula pubescens Ehrh. (Betulaceae), and aspen, Populus tremula L. (Salicaceae), were tested on spring-dispersing Tomicus piniperda (L.) and Tomicus minor (Hart.) by gas chromatographic electroantennographic detection (GC-EAD) and by attractantbaited traps in southern Sweden. GC-EAD analysis of the head-space volatiles from fresh bark chips of B. pendula revealed two green leaf alcohols, I-hexanol and (273hexen-1-01, that consistently elicited antennal responses by T. piniperda and T. minor. Further analyses with synthetic mixtures showed that the antennae of these two Tomicus species also responded to other green leaf alcohols, such as (E)-2-hexen-1-01 found from the non-host leaves, and C,-alcohols, 3-octanol and I-octen-3-01, from bark of non-host birches and aspen. No antennal responses of the Tomicus species were observed to green leaf C6-aldehydes and C6-acetate or to non-host bark volatiles like trans-conophthorin, benzaldehyde, salicylaldehyde, and benzyl alcohol. In field trapping experiments, blends of electrophysiologically active green leaf alcohols or C,-alcohols resulted in reductions (>60%) in the number of T. piniperda captured compared with that for the kairomone-baited trap. When these two blends were combined, trap catch was further reduced (90%), which was not significantly different from that for the blank control. Neither the blend of two green leaf aldehydes plus the acetate nor the bark compounds trans-conophthorin or benzyl alcohol reduced trap catches. Tomicus minor had a response pattern similar to that of T. piniperda. Hylurgops palliarus (Gyll.) (Coleoptera: Scolytidae) was attracted to the combination of kairomone and verbenone but not to kairomone and was not affected by the blends of green leaf volatiles. Our results suggest that selected leaf-bark C6-alcohols and the bark C8-alcohols may have potential in developing semiochemical-based management programs against both pine shoot beetles by repelling them from suitable breeding and feeding sites. Schlyter F, Zhang Q-H, Anderson P, Byers JA, Wadhams W, Lofqvist J, Birgersson G. 2000. RCponses Clectrophysiologiques et comportementales de Tomicus piniperda et T. minor. (Coleoptera : Scolytidae) A des substances volatiles emanant des feuilles et de I'Ccorce d'arbres non hates. The Canadian Entonzolo~ist 132 : 965-981. I Author to whom aIl correspondence should be addressed (E-mail: [email protected]).