Bark volatiles from green ash Fraxinus pennsylvanica were tested for electrophysiological activity by Agrilus planipennis using gas chromatographic-electroantennographic detection (GC-EAD) and for behavioral activity using baited purple traps in Michigan. GC-EAD analysis of the headspace volatiles of bark tissue samples from 0- and 24-h-old fully girdled (stressed) ash trees showed that the latter had elevated sesquiterpene levels. Six of the elevated compounds consistently elicited antennal responses by both male and female A. planipennis. Five of the antennally active compounds were identified as alpha-cubebene, alpha-copaene, 7-epi-sesquithujene, trans-beta-caryophyllene, and alpha-humulene (alpha-caryophyllene). The sixth EAD-active compound remains unidentified. We monitored capture of adult A. planipennis on traps baited with several combinations of ash tree volatiles. Treatments included two natural oil distillates (Manuka and Phoebe oil) that were found to contain, respectively, high concentrations of four and five of the six antennally active ash bark volatiles. A four-component leaf lure developed by the USDA Forest Service and Canadian Forest Service was also tested. In three separate field studies, Manuka oil-baited traps caught significantly more adult beetles than unbaited traps. Lures designed to release 5, 50, and 500 mg of Manuka oil per day all caught more insects than unbaited traps. In a field test comparing and combining Phoebe oil with Manuka oil, Phoebe oil-baited traps caught significantly more beetles than either Manuka oil-baited traps or unbaited traps. We hypothesize that the improved attractancy of Phoebe oil to A. planipennis over Manuka oil is caused by the presence of the antennally active sesquiterpene, 7-epi-sesquithujene.

We describe a novel and straightforward route to all stereoisomers of 1,10-bisaboladien-3-ol and 10,11-epoxy-1-bisabolen-3-ol via the rhodium-catalyzed asymmetric addition of trimethylaluminum to diastereomeric mixtures of cyclohex-2-enones 1 and 2. The detailed stereoisomeric structures of many natural sesquiterpenes with the bisabolane skeleton were previously unknown because of the absence of stereoselective syntheses of individual stereoisomers. Several of the bisabolenols are pheromones of economically important pentatomid bug species. Single-crystal X-ray crystallography of underivatized triol 13 provided unequivocal proof of the relative and absolute configurations. Two of the epoxides, (3S,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol (3) and (3R,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol (4), were identified as the main components of a male-produced aggregation pheromone of the brown marmorated stink bug, Halyomorpha halys, using GC analyses on enantioselective columns. Both compounds attracted female, male, and nymphal H. halys in field trials. Moreover, mixtures of stereoisomers containing epoxides 3 and 4 were also attractive to H. halys, signifying that the presence of additional stereoisomers did not hinder attraction of H. halys and relatively inexpensive mixtures can be used in monitoring, as well as control strategies. H. halys is a polyphagous invasive species in the U.S. and Europe that causes severe injury to fruit, vegetables, and field crops and is also a serious nuisance pest.

Halyomorpha halys (Stål), the brown marmorated stink bug, is an invasive, polyphagous insect that causes serious economic injury in particular to specialty crops in the United States. Growers have been forced to respond by increasing the frequency of broad-spectrum insecticide (e.g., neonicotinoid, pyrethroid, and carbamate) applications. One strategy to reduce reliance on insecticides is known as ''attract-and-kill'' whereby the targeted insect is attracted to a spatially precise location to be eliminated by a killing agent such as an insecticide. This approach can substantially reduce the amount of insecticide used by sparing alternate row middle or whole block sprays. For apple orchards, we propose baiting select border row trees with the H. halys aggregation pheromone and synergist and subsequently treating these baited trees with effective insecticides to kill H. halys throughout the growing season. To evaluate the behavioral basis of this approach, we conducted orchard trials with black pyramid traps, harmonic radar, and trials using baited apple trees sprayed weekly to quantify H. halys arrestment area, retention time, adult and nymph annihilation, and fruit injury in and near these attract-and-kill sites. The arrestment area for H. halys was confined to a 2.5 m radius around the pheromone-and pheromone synergist-baited trap regardless of pheromone dose (84 or 840 mg), while the retention capacity of adults was significantly increased by pairing the aggregation pheromone and synergist with a fruiting host plant compared with non-host sites. Damage to fruit harvested from baited attract-and-kill trees was high, but minimal in surrounding unbaited neighboring apple trees. Our results suggest attract-and-kill may be an effective strategy for managing H. halys season-long.Keywords Integrated pest management Á Brown marmorated stink bug Á Behaviorally based management Á Harmonic radar Á Invasive species Á Pheromone Á Hemiptera Á Pentatomidae Key messages• Halyomorpha halys management relies on repeated insecticide applications to susceptible crops. • We evaluated the behavioral basis for a proposed attract-and-kill strategy in apple as a means to reduce insecticide inputs. • We found that attract-and-kill holds promise as H. halys activity was confined to a small arrestment area around a pheromone source, and the use of harmonic radar showed that retention time at these sites was greatest when a host plant (apple) was present. • High kill of H. halys was achieved in baited attract-andkill apple trees season-long with minimal damage on adjacent unbaited trees. Communicated by T. Haye.Electronic supplementary material The online version of this article (

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