Dendroctonus pseudotsugae Hopkins (Coleoptera: Scolytidae): production of and response to enantiomers of 1-methylcyclohex-2-en-1-ol

Female Douglas-fir beetles, Dendroctonus pseudotsugae, produced an average 45:55 mixture of the (S)-(-)- and (R)-(+)-enantiomers of 1-methylcyclohex-2-en-1-ol (MCOL). The (S)-(-):(R)-(+) ratio of 3-methylcyclohex-2-en-1-ol (seudenol) produced by this population of females was 34:66. Lindgren funnel traps baited with (R)-(+)-MCOL attracted significantly more males and females than (S)-(-)-MCOL-baited traps, which captured significantly more beetles than unbaited controls. The combined effect of the enantiomers was additive, rather than synergistic. Either enantiomer of MCOL increased catches by frontalin-baited traps. Racemic MCOL can be used for trapping Douglas-fir beetles in south-central British Columbia