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 (
SignificanceMany insects release volatile terpenes for chemical communication. However, the biosynthetic origin and evolution of these infochemicals are mostly unknown. We show that the harlequin bug, Murgantia histrionica, a stink bug pest (Hemiptera) of crucifer crops, produces a terpene aggregation pheromone by an enzyme that is unrelated to microbial and plant terpene synthases. M. histrionica terpene synthase activity is highly sex- and tissue-specific and makes a sesquiterpene alcohol, so far unknown in animals, as pheromone precursor. The enzyme evolved from ancestral isoprenyl diphosphate synthases and provides new evidence for de novo biosynthesis of terpenes in hemipteran insects. Knowledge of pheromone biosynthesis in stink bugs may lead to the development of new controls of these pests.
We used pheromone-baited traps to survey the distribution of winter moth, Operophtera brumata (L.) (Lepidoptera: Geometridae), a new invasive defoliator from Europe in eastern New England. The traps also attracted Bruce spanworm, Operophtera bruceata (Hulst) (Lepidoptera: Geometridae), native to North America. We distinguished between the two species by examining male genitalia and sequencing the mitochondrial cytochrome oxidase subunit 1 (COI) gene, the DNA barcoding region. In 2005, we recovered winter moths at sites stretching from eastern Long Island, southeastern Connecticut, all of Rhode Island, eastern Massachusetts, coastal New Hampshire, and southern coastal Maine. At sites further west and north we captured only Bruce spanworm. In 2006, we confirmed that both winter moth and Bruce spanworm are present in Nova Scotia and in coastal Maine, but only Bruce spanworm was recovered in coastal New Brunswick, Canada; Pennsylvania; Vermont; or Quebec City, Canada. In 2007, we collected Bruce spanworm, but no winter moths, in New Brunswick and the interior areas of Maine, New Hampshire, and New York. Winter moth and Brace spanworm differed in the COI sequence by 7.45% of their nucleotides. The prevalence of intermediate genitalia in the zone of overlap suggested that hybridization between the two species may be occurring. To confirm the presence of hybrids, we sequenced the nuclear gene, glucose-6phosphate dehydrogenase (G6PD). We identified six nucleotides that routinely distinguished winter moth and Bruce spanworm, of which three were always diagnostic. We showed that eggs produced by hybridizing the two species in the laboratory contained copies of both species at these six sites. We found that most of the moths collected in the field with intermediate genitalia had winter moth CO1 and G6PD sequences and thus were not hybrids (or at least F1 hybrids). We found three hybrids out of 158 moths with intermediate genitalia in the region where both species were caught. We conclude that hybrids occur in nature, but are not as common as previously reported. Introgression of genes between the two species may still be significant.
The reported male-produced aggregation pheromone of the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), identified as a mixture of (3S,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol and (3R, 6S, 7R, 10S)-10,11-epoxy-1-bisabolen-3-ol, offers new opportunities for its management. We found that black pyramid traps deployed along crop borders in Maryland and West Virginia, containing lures with both stereoisomers of this reported aggregation pheromone combined with methyl (E,E,Z)-2,4,6-decatrienoate (MDT) lures, attracted more adult and nymphal H. halys than either the aggregation pheromone or MDT alone. In season-long totals, combined lures acted synergistically by catching 1.9-3.2 times more number of adults, and 1.4-2.5 times more number of nymphs, than expected from an additive effect of the lures deployed individually. There were no significant differences in patterns of male and female captures. MDT alone was not significantly attractive to adults during most of the growing season, but became increasingly attractive to adults and especially nymphs in autumn. Mixed-isomer lures containing eight stereoisomers of 10,11-epoxy-1-bisabolen-3-ol, including the two active stereoisomers, were as effective at catching adults and nymphs with or without MDT as were lures loaded only with the two active stereoisomers in the natural ratio ((3S, 6S, 7R, 10S)-10,11-epoxy-1-bisabolen-3-ol: (3R, 6S, 7R, 10S)-10,11-epoxy-1-bisabolen-3-ol) of 3.5:1. These results identify a combination of semiochemicals that is attractive season-long for detection, monitoring, and potential control of this polyphagous invasive pest of North America and Europe.
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