Attraction of Piezodorus hybneri to the Aggregation Pheromone Components of Riptortus clavatus

The aggregation pheromone of Riptortus clavatus (Heteroptera: Alydidae) consists of (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), (E)-2-hexenyl (E)-2-hexenoate (E2HE2H), and myristyl isobutyrate (MI). Experiments were conducted to examine the attraction of Piezodorus hybneri (Heteroptera: Pentatomidae) to the pheromone components of R. clavatus, individually and in combination, and to determine if P. hybneri produces these compounds. Electroantennogram (EAG) responses of P. hybneri to E2HE2H were significant in a dose dependent manner, while those to E2HZ3H were not significantly different from those to hexane and air. Field trapping tests using E2HZ3H, E2HE2H, and MI, individually or in combination, showed that only E2HE2H was attractive to P. hybneri. E2HE2H was not detected in whole-body extracts or volatile collections from either sex of P. hybneri adults. We propose that the response of P. hybneri adults to the R. clavatus aggregation pheromone may be related to finding suitable host plants.     

The aggregation pheromone of <Emphasis Type="Italic">Diorhabda elongata</Emphasis>, a biological control agent of saltcedar(<Emphasis Type="Italic">Tamarix</Emphasis> spp.): identification of two behaviorally active components

The leaf beetle Diorhabda elongata Brullé (Coleoptera: Chrysomelidae)has been introduced as a biological control agent for saltcedars, Tamarix spp., an exotic, invasive weedy tree in the western United State. Gas chromatographic (GC) analysis of volatiles collected from feeding male or female beetles, or saltcedar foliage alone, showed two components produced almost exclusively by males. These compounds elicited responses from antennae of male and female beetles in GC-electroantennographic detection (EAD) analyses. The compounds were identified as (2E,4Z)-2,4-heptadienal (1) and (2E,4Z)-2,4- heptadien-1-ol (2) by GC-mass spectrometry (MS), and confirmed with authentic standards. The two compounds were also detected at trace levels from feeding females and foliage controls, but the amounts from feeding males were 8-40 times higher, typically 55-125 ng per day per male. The amounts of 1 and 2 in collections from females did not differ significantly from amounts collected from control foliage. In field trials, 2 as a single component was as attractive as a 1:1 blend of 1 and 2. Compound 1 as a single component was more attractive than controls, but much less attractive than 2 or the blend. Males and femaleswere attracted in about equal numbers, indicating that this is an aggregation pheromone.Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Aggregation pheromone of driedfruit beetle,Carpophilus hemipterus Wind-tunnel bioassay and identification of two novel tetraene hydrocarbons

A male-produced aggregation pheromone was demonstrated inCarpophilus hemipterus (L.) (Coleoptera: Nitidulidae) using a wind-tunnel bioassay. Both sexes responded to the pheromone, but the beetles flew in the wind tunnel only after they had been starved for at least several hours. The attractiveness of the pheromone was greatly enhanced by volatiles from a food source, and combinations of pheromone and food volatiles typically attracted 3–10 times more beetles than either source by itself. A variety of food-related sources of volatiles were effective. These included apple juice; a mixture of baker's yeast plus banana; the pinto bean diet used for rearing this beetle; the chemicals propyl acetate, ethanol; and a mixture of acetaldehyde, ethyl acetate, and ethanol. The pheromonal activity resided with a series of 10 male-specific, unsaturated hydrocarbons of 13, 14, and 15 carbon atoms. These were partially separated by HPLC. No single compound was absolutely required for pheromonal activity to be observed, and various subsets of these compounds were active. The most abundant component was (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-decatetraene. One minor component was (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-undecatetraene. These structures were proven by synthesis. Together, the synthetic compounds were as active in the wind tunnel as the beetle-derived pheromone.     

Decadienoates: Sex Pheromone Components of Nettle Caterpillars Darna trima and D. bradleyi

This study was undertaken to identify sex pheromone components of nettle caterpillars Darna trima and Darna bradleyi (Lepidoptera: Limacodidae) whose larvae defoliate oil palm, Elaeis guineensis, in southeast Asia. Coupled gas chromatographic–electroantennographic detection (GCEAD) analyses of pheromone gland extracts revealed two antennally active compounds produced by female D. trima and two by female D. bradleyi. Molecular structures of these candidate pheromone components were identified by electron-impact and chemical-ionization mass spectrometry; retention-index calculations on DB-5, DB-23, and DB-210 columns; microanalytical treatments, as well as syntheses of "auxilliary" compounds that facilitated identification of the compounds. The compounds from D. trima were 2-methylbutyl (E)-7,9-decadienoate (A) and (E)-2-hexenyl (E)-7,9decadienoate (B); from D. bradleyi we identified methyl (E)-7,9-decadienoate (C), and isobutyl (E)-7,9-decadienoate (D). In field experiments in Malaysia, (S)-2-methylbutyl (E)-7,9-decadienoate (SA) in combination with B proved to be essential and synergistic pheromone components for attraction of male D. trima. (R)-2-Methylbutyl (E)-7,9-decadienoate (RA) had no behavioral activity. Compound D singly attracted male D. bradleyi, but addition of C to D at a 1 : 10 ratio significantly enhanced attractiveness of the bait. Synthetic pheromone blends were more effective trap baits than unmated female moths and could be developed for monitoring populations of D. trima and D. bradleyi in Asian oil palm plantations.     

Sex Pheromones of Two Melittini Species, <Emphasis Type="Italic">Macroscelesia Japona</Emphasis> and <Emphasis Type="Italic">M. Longipes</Emphasis>: Identification and Field Attraction

Two Melittini species, Macroscelesia japona and M. longipes (Lepidoptera: Sesiidae), are native to Japan, but occupy different localities as their host plants seldom grow together. The contents of the sex pheromone gland of adult females of both species, obtained after rearing larvae collected from the field, were investigated by gas chromatograph-electroantennogram detection (GC-EAD) and gas chromatograph-mass spectrometry (GC-MS) analyses. Two GC-EAD-active components were found in a crude extract of M. japona female pheromone gland, and identified as (2E,13Z)-2,13-octadecadien-1-ol (E2,Z13-18:OH) and (2E,13Z)-2,13-octadecadienal (E2,Z13-18:Ald). The average ratio of these two components was about 1:10. In the field, M. japona males were attracted to traps baited with E2,Z13-18:Ald alone, but the strongest attraction was observed with a 1:100 mixture of E2,Z13-18:OH and E2,Z13-18:Ald. The same two components were found in extracts of M. longipes females, but in a markedly different ratio. Male M. longipes were attracted most strongly to lures containing a 20:1 mixture of E2,Z13-18:OH and E2,Z13-18:Ald, although some males were also attracted to lures with E2,Z13-18:OH alone. Although the two species do not generally occur in sympatry, our data indicate that, in the event of overlap, cross attraction of the two species is unlikely.     

Homofarnesals: Female Sex Attractant Pheromone Components of the Southern Cowpea Weevil, <Emphasis Type="Italic">Callosobruchus chinensis</Emphasis>

The southern cowpea weevil, Callosobruchus chinensis (Coleoptera: Bruchidae), is a major pest of stored legumes in warm temperate and tropical climates. The female sex attractant pheromone was extracted from filter-paper shelters taken from containers that housed virgin females. The extracts were purified by various chromatographic techniques, and the biologically active components in the fractions were screened by gas chromatographic–electroantennographic detection analysis with male antennae. Two compounds that elicited electrophysiological responses were isolated, and gas chromatography–mass spectrometry, nuclear magnetic resonance, and micro-chemical analyses suggested that the active compounds were homofarnesals, (2Z,6E)- and (2E,6E)-7-ethyl-3,11-dimethyl-2,6,10-dodecatrienals. Males of C. chinensis were significantly attracted to filter paper discs loaded with the synthetic compounds at 0.01–0.1 ng compared to solvent control in a Y-tube olfactometer assay. These pheromone components represent unique chemical structures within the genus Callosobruchus.     

Pheromones of milkweed bugs (Heteroptera: Lygaeidae) attract wayward plant bugs: Phytocoris mirid sex pheromone

The synthetic aggregation pheromone of the large milkweed bug, Oncopeltus fasciatus (Dallas) (Lygaeinae), also attracted males of the plant bug, Phytocoris difficilis Knight (Miridae). Field testing partial blends against the six-component blend comprising the Oncopeltus pheromone showed that cross-attraction of P. difficilis males was due to synergism between (E)-2-octenyl acetate and (E,E)-2,4-hexadienyl acetate. Hexyl acetate was abundant in the metathoracic scent gland (MSG) secretion of P. difficilis males, but because female P. difficilis could not initially be found in the field, further combinatorial tests were guided by prior research on the pheromones of two Phytocoris species in the western United States. The combination of hexyl, (E)-2-hexenyl, and (E)-2-octenyl acetates was as attractive to P. difficilis males as the milkweed bug pheromone, yet no milkweed bugs were drawn to this blend. Gas chromatographic (GC)-electroantennographic detection (EAD) and GC-mass spectrometric (MS) analyses of female P. difficilis MSGs determined that their secretion contained predominantly hexyl, (E)-2-hexenyl, and (E)-2-octenyl acetates (all strongly EAD-active)—the latter two compounds found only in trace amounts from males—plus five minor female-specific compounds, three of which were EAD-active. (E,E)-2,4-Hexadienyl acetate was not detected from P. difficilis females or males. The blend of the three major components, hexyl, (E)-2-hexenyl, and (E)-2-octenyl acetates (2:1.5:1 by volume), was as attractive as the blend of all six EAD-active compounds identified from females, indicating that this ternary blend constitutes the sex pheromone of P. difficilis. Hexyl acetate with (E)-2-octenyl acetate also attracted males of another species, P. breviusculus Reuter, but addition of (E)-2-hexenyl acetate and/or (E,E)-2,4-hexadienyl acetate inhibited attraction of P. breviusculus males. Attraction of P. difficilis males occurred mainly during the first half of scotophase. The possible neurophysiological basis for this asymmetrical cross-attraction is discussed.     

(<Emphasis Type="Italic">Z,Z</Emphasis>)-6,9-Heneicosadien-11-One: Major Sex Pheromone Component Of Painted Apple Moth, <Emphasis Type="Italic">Teia anartoides</Emphasis>

(Z, Z)-6,9-Heneicosadien-11-one (Z6Z9-11-one-21Hy) was identified as the major sex pheromone component of the painted apple moth (PAM), Teia anartoides (Lepidoptera: Lymantriidae), on the basis of (1) comparative gas chromatographic-electroantennographic detection (GC-EAD) analyses, GC-mass spectrometry (MS), high-performance liquid chromatography (HPLC)-MS, and HPLC-UV/visible spectroscopy of pheromone gland extracts and authentic standards; (2) GC-EAD analyses of effluvia of calling females; and (3) wind tunnel and field trapping experiments with a synthetic standard. In field experiments in Australia, synthetic Z6Z9-11-one-21Hy as a single component attracted male moths. Wind tunnel experiments suggested that a 4-component blend consisting of Z6Z9-11-one-21Hy, (6Z,9R,10S)-cis-9,10-epoxy-heneicosene (Z6-9R10S-epo-21Hy), (E, E)-7,9-heneicosadien-6,11-dione (E7E9-6,11-dione-21Hy), and 6-hydroxy-(E, E)-7,9-heneicosadien-11-one (E7E9-6-ol-11-one-21Hy) (all present in pheromone gland extracts) might induce more males to orient toward, approach, and contact the source than did Z6Z9-11-one-21Hy as a single component. Additional experiments are needed to determine conclusively whether or not Z6-9R10S-epo-21Hy, E7E9-6,11-dione-21Hy, and E7E9-6-ol-11-one-21Hy might be minor sex pheromone components of PAM. Moreover, attractiveness of synthetic pheromone and virgin PAM females needs to be compared to determine whether synthetic pheromone could replace PAM females as trap baits in the program to monitor eradication of exotic PAM in New Zealand.     

New Pheromone Components of the Grapevine Moth <Emphasis Type="Italic">Lobesia botrana</Emphasis>

Analysis of extracts of sex pheromone glands of grapevine moth females Lobesia botrana showed three previously unidentified compounds, (E)-7-dodecenyl acetate and the (E,E)- and (Z,E)-isomers of 7,9,11-dodecatrienyl acetate. This is the first account of a triply unsaturated pheromone component in a tortricid moth. The monoenic acetate (E)-7-dodecenyl acetate and the trienic acetate (7Z,9E,11)-dodecatrienyl acetate significantly enhanced responses of males to the main pheromone compound, (7E,9Z)-7,9-dodecadienyl acetate, in the wind tunnel. The identification of sex pheromone synergists in L. botrana may be of practical importance for the development of integrated pest management systems. Electronic supplementary material Supplementary material to this paper is available in electronic form at and accessible for authorised users.     

Sex Pheromone of the Saturniid Moth, <Emphasis Type="Italic">Hemileuca burnsi</Emphasis>, from the Western Mojave Desert of California

The sex pheromone blend of Hemileuca burnsi (Lepidoptera: Saturniidae) from the western Mojave Desert was determined to be a combination of (10E,12Z)-hexadecadien-1-yl acetate (E10,Z12-16:Ac), (10E,12Z)-hexadecadien-1-ol (E10,Z12-16:OH), (10E,12E)-hexadecadien-1-yl acetate (E10,E12-16:Ac), and hexadecyl acetate (16:Ac). (10E,12Z)-Hexadecadienal (E10,Z12-16:Ald) was tentatively identified in pheromone gland extracts based on electroantennographic responses and, when added to the above blend, it enhanced trap captures at low doses. The mean ratio of the compounds in extracts of pheromone glands was 100:23:232:14:0.4 (E10,Z12-16:Ac: E10,E12-16:Ac: 16:Ac: E10,Z12-16:OH: E10,Z12-16:Ald). Field trials indicated that although E10,Z12-16:Ac and E10,Z12-16:OH were essential for attraction, the two-component blend was not attractive by itself. Addition of the three other compounds was necessary for maximum attraction, rendering this the most complicated pheromone blend described for a Hemileuca species to date. Similarities between the sex pheromone of H. burnsi and that of the allopatric Hemileuca electra electra and differences between the blends of H. burnsi and that of the sympatric H. electra mojavensis support a case for reproductive character displacement in the pheromone communication channel of H. electra.     

Identification of Sex Pheromone Components of the Hessian Fly, <Emphasis Type="Italic">Mayetiola destructor</Emphasis>

Coupled gas chromatographic (GC)–electroantennographic detection (EAD) analyses of ovipositor extract of calling Hessian fly, Mayetiola destructor, females revealed that seven compounds elicited responses from male antennae. Four of the compounds—(2S)-tridec-2-yl acetate, (2S,10Z)-10-tridecen-2-yl acetate, (2S,10E)-10-tridecen-2-yl acetate, and (2S,10E)-10-tridecen-2-ol—were identified previously in female extracts. Two new EAD-active compounds, (2S,8Z,10E)-8,10-tridecadien-2-yl acetate and (2S,8E,10E)-8,10-tridecadien-2-yl acetate, were identified by GC–mass spectroscopy (MS) and the use of synthetic reference samples. In a Y-tube bioassay, a five-component blend (1 ng (2S)-tridec-2-yl acetate, 10 ng (2S,10E)-10-tridecen-2-yl acetate, 1 ng (2S,10E)-10-tridecen-2-ol, 1 ng (2S,8Z,10E)-8,10-tridecadien-2-yl acetate, and 1 ng (2S,8E,10E)-8,10-tridecadien-2-yl acetate) was as attractive to male Hessian flies as a similar amount of female extract (with respect to the main compound, (2S,10E)-10-tridecen-2-yl acetate). The five-component blend was more attractive to male flies than a three-component blend lacking the two dienes. Furthermore, the five-component blend was more attractive than a blend with the same compounds but that contained one tenth the concentration of (2S,8E,10E)-8,10-tridecadien-2-yl acetate (more accurately mimicking the ratios found in female extract). This suggests that the ratios emitted by females might deviate from those in gland extracts. In a field-trapping experiment, the five-component blend applied to polyethylene cap dispensers in a 100:10 μg ratio between the main component and each of the other blend components attracted a significant number of male Hessian flies. Also, a small-plot field test demonstrated the attractiveness of the five-component blend to male Hessian flies and suggests that this pheromone blend may be useful for monitoring and predicting Hessian fly outbreaks in agricultural systems.     

Sex Pheromone of <Emphasis Type="BoldItalic">Lonomia obliqua</Emphasis>: Daily Rhythm of Production,Identification, and Synthesis

The sex pheromone of Lonomia obliqua Walker (Lepidoptera: Saturniidae) was studied in the laboratory. All female calling occurred during the scotophase. Most females (70.6%) called first within 24 hr of eclosion. Calling varied with age of female, with older (5- to 6-day-old) females calling earlier in the scotophase and for longer durations than younger (0- to 1-day-old) females. The sex pheromone gland of 1- to 3-day-old virgin females was extracted during the calling peak. A Y-olfactometer bioassay showed significant attraction of males to a filter paper containing the female gland extract. Gas chromatographic-electroantennogram detection (GC-EAD) analysis of the extract indicated the presence of at least two possible pheromone components. Gas chromatographic-mass spectrometric analysis of the major GC-EAD-active peak indicated a hexadecenyl acetate; chemical derivatization indicated Δ11 unsaturation. Synthetic samples of (E)- and (Z)-11-hexadecenyl acetate were obtained by coupling 10-bromo-1-decanol and 1-hexyne, utilizing lithium chemistry. The comparison of the retention time of dimethyl disulfide derivatives of the natural compound, to those of synthetic chemicals, confirmed the natural compound as (E)-11-hexadecenyl acetate. The minor component was identified as the related alcohol, (E)-11-hexadecenol. The ratio of the two components in female extract was 100:35. Preliminary tests of males in a Y-olfactometer showed that their response to a mixture of the two compounds was not significantly different from that to gland extract.     

Aggregation pheromone of square-necked grain beetle,Cathartus quadricollis (Guér.)

When feeding on rolled oats, male square-necked grain beetles,Cathartus quadricollis (Guér.), produced the aggregation pheromone (3R,6E)-7-methyl-6-nonen-3-yl acetate, for which the trival name quadrilure is proposed. The pheromone was highly attractive to both sexes in a two-choice, pitfall olfactometer modified to retain responding beetles by placing a food stimulus (an oat flake) in the glass vials containing the experimental and control stimuli. TheS enantiomer of the pheromone was inactive. Males also produced small amounts of (E)-7-methyl-6-nonen-3-one, (E)-7-methyl-6-nonen-3-ol, and (6E)-7-methyl-3-propyl-2,6-nonadienyl acetate, but these compounds were inactive in the laboratory bioassay. Segregated males and females both produced (R)-(–)-1-octen-3-ol, which by itself was repellent to both sexes but did not diminish beetle response to the aggregation pheromone.Coleoptera: Cucujidae.Research supported by the Natural Sciences and Engineering Research Council of Canada, Strategic Grant G1039 and Operating Grants A3881 and A3706.     

Sex Pheromone of the Dogwood Borer, <Emphasis Type="Italic">Synanthedon scitula</Emphasis>

The sex pheromone of female dogwood borers (DWB) Synanthedon scitula (Harris) (Lepidoptera: Sesiidae) was determined to be an 88:6:6 ternary blend of (Z,Z)-3,13-octadecadienyl acetate (Z,Z-3,13-ODDA), (E,Z)-2,13-octadecadienyl acetate (E,Z-2,13-ODDA), and (Z,E)-3,13-octadecadienyl acetate (Z,E-3,13-ODDA) by gas chromatography–electroantennographic detection (GC–EAD) and gas chromatography–mass spectrometry (GC–MS). The major sex pheromone component, Z,Z-3,13-ODDA, was attractive as a single component. A blend of Z,Z-3,13-ODDA with 1–3% of E,Z-2,13-ODDA (binary blend) was more attractive than the single component. A third component, Z,E-3,13-ODDA, was sometimes observed in GC–EAD analyses, and enhanced attraction to the binary blend in some field bioassays. Lures containing 1 mg of binary and ternary blends attracted 18 and 28 times more male DWB moths, respectively, than caged virgin females in field trials. Attraction was strongly antagonized by addition of as little as 0.5% of E,Z-3,13-octadecadienyl acetate (E,Z-3,13-ODDA). In a period of 12 wk in 2004, more than 60,000 males were captured in sticky traps baited with synthetic pheromone blends in six apple orchards in Virginia, West Virginia, and North Carolina. Lure longevity trials showed that ∼76% of the pheromone remained in rubber septum lures after 12 wk in the field.     

Parthenogenesis,calling behavior,and insect-released volatiles of leafminer moth Phyllonorycter emberizaepenella

We proved that the leafminer moth Phyllonorycter emberizaepenella (Lepidoptera: Gracillariidae) reproduces by parthenogenesis of the thelytoky type. Despite a complete absence of males, parthenogenetically reproducing females diurnally demonstrated the calling posture normally used for releasing signaling compounds. Two compounds, which we collected from a calling female, were identified as potential sex pheromone components: (8E,10E)-8,10-tetradecadienyl acetate and (8E,10E)-8,10-tetradecadienol, the latter occurring only in trace amounts. In field experiments, no males were attracted to traps baited with either the potential sex pheromone or with virgin females. Both the pattern of behavior and the chemical characteristics of the pheromone of Ph. emberizaepenella species were similar to those known for Lepidoptera with the usual amphimictic mode of reproduction. Theoretical speculations that in thelytoky, where there is no need to find a sexual partner, the individuals would obtain certain advantages due to reduction in their sexual behavior, were, thus, not confirmed for Ph. emberizaepenella.     

Identification of the Larval Aggregation Pheromone of Codling Moth, <Emphasis Type="Italic">Cydia pomonella</Emphasis>

Mature larvae of the codling moth, Cydia pomonella L. (Lepidoptera: Olethreutidae), exit the fruit and seek sites suitable for pupation. Spinning cocoons in such sites, larvae produce a complex, cocoon-derived blend of volatiles recently shown to attract and/or arrest both conspecific larvae and the prepupal parasitoid Mastrus ridibundus Gravenhorst (Hymenoptera: Ichneumonidae). Here we report components of this blend that constitute the pheromone of fifth-instar C. pomonella larvae. Thirty-one two-choice olfactometer experiments showed that a blend of synthetic (E)-2-octenal, (E)-2-nonenal, sulcatone, and geranylacetone, in combination with either 3-carene and/or three saturated aldehydes (octanal, nonanal, decanal), elicited behavioral responses from C. pomonella larvae. In on-tree experiments with corrugated cardboard bands as pupation sites for larvae affixed to tree trunks, and with laboratory-reared larvae released onto such trees, more larvae cocooned in those halves of cardboard bands baited with cocoon-spinning conspecific larvae, or with synthetic pheromone components, than in unbaited control halves of the bands. With the larval aggregation pheromone identified in this study, there might be an opportunity to manipulate C. pomonella larvae in commercial fruit or nut orchards.     

Isolation,identification, and synthesis of sex pheromone components of female tea cluster caterpillar,Andraca bipunctata walker (Lepidoptera: Bombycidae) in Taiwan

Octadecanal (18:Ald), (E)-11-octadecenal (E11–18:Ald), (E)-14-octadecenal (E14–18:Ald) and (E,E)-11,14-octadecadienal (E11,E14–18:Ald) were isolated and identified as major components from the pheromone glands of the tea cluster caterpillar,Andraca bipunctata, in Taiwan by analyzing the mass spectra of gland components and their DMDS adducts. GC retention times and mass spectra of the components were in agreement with those of authentic synthetic compounds. The average amount of 18:Ald,E11–18:Ald,E14–18:Ald andE11,E14–18:Ald per female gland (1 to 3 days old) was 121±76, 50±20, 187±75, and 237±110 ng, respectively, in a ratio of 20:8:31:41. SyntheticE11,E14–18:Ald caught more males than each of the other three components or blank control in field trapping tests.E11,E14–18:Ald is reported as an insect sex pheromone for the first time. Male antenna responded toE11,E14–18:Ald strongly in an EAG analysis. Furthermore, 4 hr after the injection of PBAN (pheromone biosynthetic activating neuropeptide) into decapitated female moths (2 days old), the percentage of theE11,E14–C18 Ald in the gland extract increased from 0% to 75.5%, which was also significantly more than that of unligated and uninjected control at 55.1%. All these data indicated thatE11,E14–18:Ald is the sex pheromone of theAndraca bipunctata in Taiwan.     

Investigation of Long-Range Female Sex Pheromone of the European Tarnished Plant Bug, Lygus rugulipennis: Chemical, Electrophysiological, and Field Studies

The European tarnished plant bug, Lygus rugulipennis, is an important pest of agricultural and horticultural crops throughout Europe. Adult male L. rugulipennis were previously shown to be attracted to traps baited with live virgin females, which suggests the females produce a sex pheromone. Volatiles produced by virgin female L. rugulipennis were shown to contain three components, hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal which elicited electroantennographic (EAG) responses from males in analyses by linked gas chromatography-electroantennography (GC-EAG). They were produced in 1.5:1:0.08 ratio, respectively, by single females. Collections from 1, 2, or 4 virgin females showed the proportions of hexyl butyrate and (E)-4-oxo-2-hexenal to increase relative to that of (E)-2-hexenyl butyrate with increasing number of females. Although these compounds were found in body extracts of both male and female L. rugulipennis, they were not detected in volatiles released by virgin males. EAG dose-response studies showed that both males and females responded to these chemicals with minimal differences in sensitivity between the sexes or to the three components, except that males were more responsive than females to (E)-4-oxo-2-hexenal at the two highest doses tested. Release rates of the compounds from rubber septa, polyethylene vials, and polyethylene sachets were measured under laboratory conditions. Four field tests were carried out using sticky traps baited with all possible binary and tertiary combinations of the three chemicals using different combinations of dispensing systems. Catches of male L. rugulipennis in baited traps were similar to those in unbaited traps. Significantly fewer females were caught on traps baited with blends containing hexyl butyrate than on traps without hexyl butyrate or unbaited traps in one test and overall. The roles of the three compounds and possible reasons for their failure to attract males are discussed.     

Male-Produced Aggregation Pheromone of the Cerambycid Beetle <Emphasis Type="Italic">Rosalia funebris</Emphasis>

We report the identification, synthesis, and field bioassays of a volatile, male-produced aggregation pheromone of a long-horned beetle, the banded alder borer, Rosalia funebris Mots. Headspace collections from males contained a major male-specific compound, (Z)-3-decenyl (E)-2-hexenoate, and several minor components, identified as (Z)-3-decenol, (Z)-3-nonenyl (E)-2-hexenoate, and (Z)-3-decenyl (E)-3-hexenoate. The antennae of both males and females responded strongly to (Z)-3-decenyl (E)-2-hexenoate. We collected significant numbers of adult R. funebris in field bioassays using traps baited with this compound. This pheromone structure is unprecedented in the literature of cerambycid pheromones and distinct from the more common diol/hydroxyketone pheromone motif of many other species of the diverse subfamily Cerambycinae. This is the first pheromone identified for a species in the tribe Rosaliini. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Male-Produced Aggregation Pheromone Compounds from the Eggplant Flea Beetle (Epitrix fuscula): Identification, Synthesis, and Field Biossays

Volatiles from the eggplant flea beetle, Epitrix fuscula Crotch (Coleoptera: Chrysomelidae), feeding on host foliage, were investigated. Six male-specific compounds were detected and were identified through the use of mass spectrometry, nuclear magnetic resonance (NMR) spectrometry, chiral and achiral gas chromatography, high-performance liquid chromatography, electrophysiology (gas chromatography-electroantennography, GC–EAD), and microchemical tests. The two most abundant of the six compounds were (2E,4E,6Z)-2,4,6-nonatrienal (1) and (2E,4E,6E)-2,4,6-nonatrienal (2). The other four compounds, present in minor amounts, were identified as himachalene sesquiterpenes; two of these, 3 and 4, were hydrocarbons and two, 5 and 6, were alcohols. All four sesquiterpenes were previously encountered from male flea beetles of Aphthona spp. and Phyllotreta cruciferae. Synthetic 1 and 2 matched the natural products by GC retention times, mass spectra, and NMR spectra. Sesquiterpenes 3–6 similarly matched synthetic standards and natural samples from the previously studied species in all ways, including chirality. Both natural and synthetic 1 and 2 gave positive GC–EAD responses, as did sesquiterpenes 3, 5, and 6. Field trials were conducted with a mixture of 1 and 2, and the baited traps were significantly more attractive than control traps to both male and female E. fuscula. The E. fuscula pheromone has potential for monitoring or controlling these pests in eggplants.Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the Department of Agriculture.