Responses by five species of cucujid grain beetles (mixed-sex adults) to various volatiles were assessed by means of a two-choice, pitfall olfactometer. The test volatiles were short-chain alcohols and ketones known to be produced by fungi. Both racemic and chiral 1-octen-3-ols were strong attractants forCryptolestes ferrugineus (Stephens), as had been found previously forOryzaephilus surinamensis (L.),O. mercator (Fauvel), andAhasverus advena (Waltl). 3-Methylbutanol was another good attractant for these four cucujids, and it was the only test compound to whichCathartus quadricollis (Guér.) responded positively. 1-Octen-3-one, racemic 3-octanol, and 3-octanone showed various degrees of attractiveness for the former four species of cucujids.O. surinamensis was the only species of test beetle to show much positive response to 2-phenylethanol and ethanol. ForO. mercator andO. surinamensis, 3-methylbutanol enhanced positive response to their respective cucujolide aggregation pheromones.

Two biologically active macrolides were isolated from Porapak Q-captured beetle and frass volatiles ofCryptolestes turcicus (Grouvelle) and identified spectroscopically as (Z,Z)-5,8-tetradecadien-13-olide (I) and (Z)-5-tetradecen-13-olide (II). Natural I was active alone and was synergized by inactive II. The pheromones were male-produced but attractive to both sexes. Pheromone production increased dramatically when insects were aerated on a food source. Pure (R)- and (S)-I were inactive, but mixtures of (R)- and (S)-I were active, the first reported instance of enantiomeric synergism in the Cucujidae.

The most prominent beetle-produced volatiles identified in the abdominal extracts of maleDryocoetes confusus Swaine after they had bored for 24 hr in logs of subalpine fir,Abies lasiocarpa (Hook.) Nutt. were:exo andendo-brevicomin,trans-verbenol, verbenone, myrtenol,trans-pinocarveol,cis- andtrans-p-menthen-7-ol, 3-caren-10-ol, and several monoterpenes and sesquiterpenes. Myrtenol was the only conspicuous compound in extracts from males that had been exposed toA.lasiocarpa resin volatiles for 24 hr. Laboratory bioassays indicated that both (-)- and (+)-exo-brevicomin were attractive to femaleD. confusus, and that the (-) enantiomer did not inhibit response to its antipode. Results from field trapping experiments indicated that bothero-brevicomin and myrtenol are aggregation pheromones forD. confusus.exo-Brevicomin baits were effective in causing attack byD. confusus on baited and surrounding trees, suggesting that this pheromone may have utility in manipulating populations of the beetle.

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.

The feeding deterrent activity of fractions from the foliage of western red cedar,Thujaplicata Donn, was studied in laboratory bioassays using the white pine weevil,Pissodes strobi Peck, as a test insect. The most active fraction was the volatile mixture that comprises the leaf oil of this tree species. Further fractionation of the leaf oil indicated feeding deterrent activity in the monoterpene hydrocarbon, thujone, and terpene alcohol fractions. When tested alone, both (-)-3-isothujone and (+)-3-thujone, which made up 75-88% and 5-10% of the leaf oil, respectively, deterred feeding by the weevils. Western red cedar leaf oil also showed antifeedant activity with the alder flea beetle,Altica ambiens (Le Conte), and served as an oviposition deterrent for the onion root maggot,Hylemya antiqua Meigen. The leaf oil, however, had no inhibitory effect on the feeding of the leaf roller,Epinotia solandriana L., and the red-backed sawfly,Eriocampa ovata L.