Identification of female sex pheromone of a plant bug,Adelphocoris fasciaticollis Reuter (Hemiptera: Miridae)

The plant bug, Adelphocoris fasciaticollis, has begun to resurge and become a key pest for cotton and alfalfa in northern China, along with the widespread cultivation of Bt cotton. To control this plant bug without pesticides, we attempted to develop a new approach by utilizing sex pheromone. The sex pheromone components from the whole‐body extracts were analysed by GC‐MS and gas chromatography–electroantennogram detector analysis (GC‐EAD). (E)‐4‐Oxo‐2‐hexenal and hexyl butyrate, identified as the major components in the extracts of female bugs, elicited strong EAD responses. Field tests indicated that either (E)‐4‐oxo‐2‐hexenal or hexyl butyrate attracted few A. fasciaticollis males and was significantly less active than virgin females and the binary blend. Their ratio was optimized to be 1 : 11. Our results could expand acknowledge of the pheromone of mirids and provide novel approaches to monitor and control this plant bug without pesticides.     

Sex pheromone components of the carpenterworm moth,Holcocerus vicarius

Extracts of the female sex pheromone gland of the carpenterworm moth, Holcocerus vicarius (Walker) (Lepidoptera: Cossidae), a pest of Ulmus pumila L. (Ulmaceae), were found to contain Z7‐tetradecenyl acetate (Z7‐14Ac), E3‐tetradecenyl acetate (E3‐14Ac), (Z3,E5)‐tetradecenyl acetate (Z3,E5‐14Ac), and Z7‐tetradecenyl alcohol (Z7‐14OH) by coupled gas chromatographic‐electroantennographic detection (GC‐EAD) and coupled gas chromatography‐mass spectrometry (GC‐MS). Field trapping studies with impregnated rubber septa indicated that Z7‐14Ac was essential for attraction of males of H. vicarius. However, the most attractive blend contained Z7‐14Ac, E3‐14Ac, Z3,E5‐14Ac, and Z7‐14OH in a 50:22:17:10 ratio. Our results demonstrated that a blend of Z7‐14Ac, E3‐14Ac, Z3,E5‐14Ac, and Z7‐14OH represented the sex pheromone of H. vicarius. The optimized four‐component lure blend may be useful for monitoring H. vicarius infestations and mating disruption.     

Female sex pheromone of a nettle caterpillar,Monema flavescens,in China

Monema flavescens Walker (Lepidoptera: Limacodidae) is a multivoltine, generalist moth whose larvae cause serious damage to many types of trees. Pheromone lures prepared according to a study of a Japanese population were found to be ineffective at attracting M. flavescens nettle caterpillars in China, and some studies have shown intraspecific geographical differences in the composition of sex pheromones. We therefore reexamined the sex pheromone composition of M. flavescens in a Chinese population. In this study, the electroantennographically (EAG) active compounds in an extract from Chinese virgin females of M. flavescens were identified as (E)‐8‐decen‐1‐ol (E8‐10:OH), (Z)‐7,9‐decadien‐1‐ol (Z7,9‐10:OH), (Z)‐9,11‐dodecadien‐1‐ol (Z9,11‐12:OH), and (Z)‐9,11‐dodecadienal (Z9,11‐12:Ald) via coupled gas chromatographic‐electroantennographic detection (GC‐EAD) and coupled GC‐mass spectrometry (MS). Pheromone dimorphism might occur in this species, as this mixture of compounds in Chinese females was different from that of E8‐10:OH and E7,9‐10:OH extracted from Japanese females in previous research. In wind tunnel and field tests, the males were significantly attracted to a blend of the pheromone components E8‐10:OH, Z7,9‐10:OH, and Z9,11‐12:OH in a 100:5:4 ratio. The addition of Z9,11‐12:Ald did not change the male response. The optimized three‐component lure blend may provide a useful tool for monitoring and controlling Chinese populations of M. flavescens.     

Concentration of air-borne pheromone required for long-lasting peripheral adaptation in the obliquebanded leafroller, Choristoneura rosaceana

Abstract. Electroantennogram (EAG) responses of male obliquebanded leafrollers, Choristoneura rosaceana (Harris), to the main component of its pheromone blend and traces of geometric isomer ((Z)11‐14:Ac and (E)11‐14:Ac, respectively) were recorded before and after 1 h of continuous exposure to pheromone in laboratory experiments, and 24 h of exposure under field conditions. Concentrations of pheromone ranging from 56 to below 1 ng mL^?1 air in Teflon chambers with regulated air exchange reduced peripheral sensory responses by 40–60% as measured by amplitudes of the EAG. Adaptation did not increase in a dosage‐dependent fashion over most of this range; an identical reduction of responsiveness was observed at each exposure to an effective concentration. Exposure of C. rosaceana at a loading dosage of 1 ng of pheromone in 100 µL of mineral oil (air concentration below the GLC detection limit) did not induce measurable adaptation. Caging C. rosaceana in apple trees adjacent to one, two or four Isomate OBLR/PLR Plus polyethylene pheromone dispensers for 24 h resulted in long‐lasting adaptation similar to that seen in laboratory experiments. Adaptation was not observed for C. rosaceana caged at a distance of 2 m from Isomate dispensers in 1‐ha plots treated with 500 dispensers per ha. Whenever observed, this type of adaptation was expressed for more than 5 min after exposure to pheromone ceased. Collectively, this adaptation phenomenon in C. rosaceana is consistent with the third of Zufall & Leinders‐Zufall's types of olfactory adaptation that is ‘long‐lasting’. Although the dosage of pheromone required to induce long‐lasting adaptation in this moth is judged high relative to that for normal sexual communication, we suggest this type of adaptation may come into play for some but not all moths under pest‐control regimes using the tactic of pheromone‐disruption, particularly those using high‐dosage release technologies like pheromone rope dispensers or Microsprayers.     

Sex pheromone of the iris gelechiid moth Monochroa divisella

The iris gelechiid moth, Monochroa divisella (Douglas) (Lepidoptera: Gelechiidae), is a serious pest in iris horticulture. The overuse of pesticides for conventional control has a great risk of water pollution because irises are often planted in damp areas. To minimize pesticide applications, it is essential to monitor moth emergence by using pheromone traps. The female pheromone of M. divisella was analyzed by means of gas chromatography‐electroantennographic detection (GC‐EAD) and GC‐mass spectrometry. Two male EAD‐active compounds were detected and identified as (Z)‐3‐dodecenyl acetate (Z3‐12:Ac) and (Z)‐5‐tetradecenyl acetate (Z5‐14:Ac), the amounts of which were ca. 40 and 6 ng per female (100:15), respectively. Synthetic Z3‐12:Ac alone attracted only a few males in field trap experiments, but the attractiveness was significantly enhanced when 15% (wt/wt) Z5‐14:Ac was added; traps baited with their binary mixtures captured 21.3‐106.4 males/trap/day, as compared with 2.3 males/trap/day attracted by a crude extract of 10 virgin females. We conclude that Z3‐12:Ac and Z5‐14:Ac are M. divisella pheromone components, which can be offered as an attractant in monitoring traps. Although dodecenyl acetates are a major class of lepidopteran pheromone components, those with the double bond at the 3 position are rare and appear to be unique to gelechiids.     

Sex pheromone of the butterbur borer, Ostrinia zaguliaevi

The sex pheromone blend of the butterbur borer, Ostrinia zaguliaevi (Lepidoptera: Pyralidae) was analyzed by means of gas chromatography-electroantennographic detection (GC-EAD), GC-mass spectrometry and a series of wind-tunnel bioassays. Four EAD-active compounds were detected in the female sex pheromone gland extract, and these were identified as tetradecyl acetate (14:OAc), (Z)-9-tetradecenyl acetate (Z9-14:OAc), (E)-11-tetradecenyl acetate (E11-14:OAc) and (Z)-11-tetradecenyl acetate (Z11-14:OAc). The average amounts ± s.d. of the four compounds in a single sex pheromone gland were 7.9±3.7 ng, 10.1±3.2 ng, 1.1±0.5 ng and 11.6±5.1 ng, respectively. In a wind-tunnel bioassay, the ternary blend of Z9-, E11- and Z11-14:OAc at a ratio found in the sex pheromone gland (45:5:50) elicited the same behavioral responses from the males as did virgin females and pheromone gland extract. Removal of any single compound from the ternary blend significantly diminished the pheromonal activity, whereas addition of 14:OAc to the ternary blend had no effect on the males' behavioral responses. Therefore, it was concluded that the sex pheromone blend of O. zaguliaevi is composed of Z9-14:OAc, E11-14:OAc and Z11-14:OAc at a ratio of 45:5:50.     

Effect of diapause status and gender on activity,metabolism, and starvation resistance in the plant bug Lygus hesperus

Lygus hesperus Knight (Hemiptera: Miridae), a key pest species distributed throughout the western USA, survives winter in a state of diapause. A laboratory population was examined to elucidate the changes in behavior and physiology linked to this period of dormancy and to determine how these changes are affected by gender. It was found that under starvation conditions, diapausers lived significantly longer compared to non‐diapausers in both genders. This may be attributable to the greater lipid reserves that diapausers have compared to non‐diapausers. Diapausers also spent more time at rest and less time feeding than non‐diapausers. Gender did not impact these behaviors. There was no difference in resting metabolic rate or flight activity between diapausers and non‐diapausers, however, there were significant gender differences when the data were pooled. Males had higher resting metabolisms than females, whereas females spent more time flying. Collectively, these results point toward a higher degree of resource conservation in diapausers. These differences may enhance resistance to starvation and dehydration conditions that L. hesperus are likely to encounter while overwintering.     

Essential oils as spatial repellents for the brown marmorated stink bug,Halyomorpha halys (Stål) (Hemiptera: Pentatomidae)

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), native to Northeastern Asia, is a serious invasive pest in the United States, Canada, Switzerland, Germany and France. Several common essential oils and their compositions were tested against BMSBs as potential repellents. All the tested individual essential oils and a ternary oil blend showed significant repellency to both BMSB nymphs and adults. Clove oil, lemongrass oil, spearmint oil, ylang‐ylang oil, and the ternary oil mixture (clove, lemongrass and spearmint) almost completely blocked attraction of BMSBs to the stink bug attractant‐baited traps; whereas wintergreen oil, geranium oil, pennyroyal oil and rosemary oil resulted in 60–85% trap catch reductions. Over 20 BMSB antennally active compounds were identified from SPME headspace samples of the eight repellent essential oils using GC‐EAD and GC‐MS techniques. Among the synthetic EAD‐active compounds tested in the field, eugenol, l‐carvone, p/l‐menthone, pulegone, methyl salicylate, trans/cis‐citral, methyl benzoate and β‐caryophyllene significantly reduced trap catches of BMSBs by 72–99%; these compounds are likely responsible for the repellency of their corresponding essential oils. Surprisingly, a synthetic mixture of the predacious spined soldier bug (SSB) [Podisus maculiventris (Say)] aggregation pheromone (trans‐2‐hexenal, α‐terpineol and benzyl alcohol) also showed a significant inhibition of BMSB response to its attractants. These repellent essential oils and their active compounds, as well as the synthetic SSB pheromone, are potentially useful as part of an efficient, environmentally sound semiochemical‐based IPM programme to combat this serious invasive stink bug.     

Large‐scale mating disruption of Ephestia spp. and Plodia interpunctella in Czech Republic,Greece and Italy

Field trials were carried out to evaluate the use of the pheromone (9Z,12E)‐tetradecadienyl acetate (TDA/ZETA) for mating disruption (MD) of Pyralidae moths associated with stored products, in most cases the Raisin moth, Ephestia cautella (Walker), Mediterranean flour moth, Ephestia kuehniella Zeller and Indianmeal moth, Plodia interpunctella (Hübner). The experiments were conducted in the Czech Republic, Greece and Italy during 2007 and 2008 in storage facilities that varied in their size and type, and included flour mills, retail stores, storage rooms with currants and raw grain stores. After a summer pre‐treatment monitoring period to assess moth population in, dispensers containing TDA were placed in the fall. Adjacent facilities without dispensers were used as control units. Pheromone‐baited traps were used to monitor the population fluctuation of the pyralid moths during the entire experimental periods. The presence of MD dispensers notably reduced the number of adults found in the traps in comparison with control rooms. Monitoring of female oviposition, measured as number of hatched larvae in cups containing food, indicated that there was a reduction in the number of larvae in the areas with MD dispensers. The results of the present work indicate that the use of mating disruption is feasible against pyralid moths in storage facilities, and should be further evaluated as a component of an integrated pest management based control strategy.     

Sex pheromone biosynthesis in the Asian corn borer Ostrinia furnacalis (II): Biosynthesis of (E)- and (Z)-12-tetradecenyl acetate involves Δ14 desaturation

Sex pheromone biosynthesis in the Asian corn borer Ostrinia furnacalis was studied by topical application of deuterium labelled fatty acids to the pheromone gland. The incorporation of the labelled acids into pheromone components and precursors was determined by gas chromatography with flame ionization detection and mass spectrometry in the selected ion monitoring mode. The labelling experiments suggest that the pheromone components (E)- and (Z)-12-tetradecenyl acetates are biosynthesized from palmitic acid by δ14 desaturation, followed by chain shortening (β-oxidation), reduction, and acetylation. This is the first confirmation of a Δ14 desaturase in an eukaryotic system.     

Males of the predatory mirid bug Macrolophus caliginosus exploit plant volatiles induced by conspecifics as a sexual synomone

The olfactory responses of male and female Macrolophus caliginosus Wagner (Heteroptera: Miridae) adults towards volatiles from green bean plants previously exposed to feeding by conspecifics and to direct odours from conspecifics were tested in a Y-tube olfactometer. Female M. caliginosus did not respond to volatiles from plants exposed to mirid feeding or to odours emitted directly by adult mirids. In contrast, male mirid bugs were attracted both to volatiles from plants previously exposed to feeding by conspecific females and to odours emitted by conspecifics only with a marginally significant preference for the former. The gas chromatography-mass spectrometry analysis showed that mirid feeding induced the release of 11 additional compounds as compared to the volatiles emitted from clean plants. Three of these substances (5-ethyl-2(5H)-furanone, Z-3-hexenyl tiglate, and E,E-α-farnesene) were released only after feeding by females. Furthermore, 21 compounds were identified in volatiles emitted directly by mirids, 12 of which were unique to the mirids (i.e., not present in clean plants or plants previously exposed to mirid feeding). The results suggest that female-specific herbivore-induced plant volatiles play a role as mate-finding cues by the male mirids. The ecological implications of the findings are discussed, and the term ‘sexual synomone’ is introduced.     

Antennal and behavioural responses of the spruce seed moth,Cydia strobilella,to floral volatiles of Norway spruce,Picea abies,and temporal variation in emission of active compounds

We investigated whether spruce seed moth, Cydia strobilella L. (Lepidoptera: Tortricidae, Grapholitini), one of the most damaging seed predators on Norway spruce, Picea abies (L.) H. Karst (Pinaceae), uses olfactory cues during host search. Analyses with coupled gas chromatography and electroantennography revealed that antennae of both sexes of moths responded consistently to three compounds in the headspace from female spruce flowers, i.e., α‐pinene, β‐pinene, and myrcene, but not to limonene as has been previously reported for this species. The amounts of these active volatiles released from flowers and cones of P. abies were quantified, and their diurnal and seasonal variation was monitored. The total release of the active volatiles correlated well with the diurnal and seasonal flight activity of C. strobilella as revealed by catches of males in pheromone‐baited traps. In field trapping experiments, where baits were loaded with proportions and enantiomeric ratios of α‐pinene, β‐pinene, and myrcene matching those of the female P. abies floral headspace, substantial catches of male C. strobilella were achieved, whereas few females were captured. These surprising results suggest that male C. strobilella make use of host volatiles to aid them in their search for females.     

Synthesis of (3E, 5Z)-3,5-Dodecadienylacetate,the Sex Pheromone of Phtheochroa cranaodes (Lepidoptera: Tortricidae)

(3E, 5Z)-3,5-Dodecadienyl acetate, the female sex pheromone of Phtheochroa cranaodes, was regio and stereo-selectively synthesized from 1-octyne and (E)-4-bromo-3-buten-1-ol by using Pd(PPh₃)₄, CuI and piperidine to afford the enyne (5). Further elaboration afforded the target pheromone. The synthetic pheromone was identified with the natural product by its MS and IR, data GLC retention time and biological activity.     

Imidazole dipeptides can quench toxic 4‐oxo‐2(E)‐nonenal: Molecular mechanism and mass spectrometric characterization of the reaction products

Imidazole dipeptides, such as carnosine (β‐alanyl‐l ‐histidine) and anserine (β‐alanyl‐N^π‐methyl‐l ‐histidine), are highly localized in excitable tissues, including skeletal muscle and nervous tissue, and play important roles such as scavenging reactive oxygen species and quenching reactive aldehydes. We have demonstrated several reactions between imidazole dipeptides (namely, carnosine, and anserine) and a lipid peroxide‐derived reactive aldehyde 4‐oxo‐2(E)‐nonenal. Seven carnosine adducts and two anserine adducts were characterized using liquid chromatography/electrospray ionization‐multiple‐stage mass spectrometry. Adduct formation occurred between imidazole dipeptides and 4‐oxo‐2(E)‐nonenal mainly through Michael addition, Schiff base formation, and/or Paal‐Knorr reaction. The reactions were much more complicated than the reaction with a similar lipid peroxide‐derived reactive aldehyde, 4‐hydroxy‐2(E)‐nonenal.     

Composition of the leaf, stem bark and root bark oils of Isolona cooperi investigated by GC (retention index), GC-MS and 13C-NMR spectroscopy

The leaf, stem bark and root bark oils of Isolona cooperi Hutchinson & Dalziel from the Ivory Coast have been analysed by GC (retention index), GC-MS and 13C-NMR spectroscopy. Two types of essential oil were produced by the plant. The leaf and stem bark oils were monoterpene-rich, containing principally (Z)-beta-ocimene and gamma-terpinene and three lactones, 5-[(E and Z)-hexylidene]-5H-furan-2-ones and massoia lactone, were present in appreciable amounts. Conversely, the root bark oil was dominated by 5-isopentenylindole and (E)-beta-caryophyllene. The strategy for the analysis of each oil was adapted according to the nature of the components.     

Enantiomers of fuscumol acetate comprise the aggregation‐sex pheromone of the South American cerambycid beetle Psapharochrus maculatissimus,and likely pheromones of the cerambycids Eupromerella plaumanni and Hylettus seniculus

There is increasing evidence that pheromone chemistry within the large coleopteran family Cerambycidae is often highly conserved, with numerous related species sharing the same pheromone components. As a result, traps containing these components can attract multiple cerambycid species simultaneously. In the present study, we exploited this concept in the identification of the male‐produced aggregation‐sex pheromone of the South American species Psapharochrus maculatissimus (Bates) (Coleoptera: Cerambycidae, subfamily Lamiinae, tribe Acanthoderini). Initially, live adults of both sexes were caught using a trap baited with a lure containing a blend of known cerambycid pheromone components. Headspace volatiles were collected from live beetles and analyzed by coupled gas chromatography‐mass spectrometry. Males of P. maculatissimus sex‐specifically produced a 1:38 blend of (R)‐fuscumol acetate ([2R,5E]‐6,10‐dimethylundeca‐5,9‐dien‐2‐yl acetate) and (S)‐fuscumol acetate, which were both components of the pheromone lures to which they had been attracted. In more focused field trials, traps baited with the (S)‐enantiomer, or a blend approximating the natural 1:38 ratio of (R)‐ to (S)‐enantiomers, attracted adults of both sexes in approximately equal numbers. During bioassays, adults of the lamiine species Eupromerella plaumanni (Fuchs) (tribe Acanthoderini) and Hylettus seniculus (Germar) (Acanthocinini) also were attracted, but to different lures, with E. plaumanni being attracted to the racemic mixture of the two enantiomers of fuscumol acetate, whereas H. seniculus was attracted specifically to (R)‐fuscumol acetate. Our results suggest that differences between these sympatric species in the stereochemistry of fuscumol acetate impart species‐specificity to pheromone communication channels, similar to what has been found recently with lamiine species from other continents.     

Optimization of pheromone lure and trap design for monitoring the fir coneworm, Dioryctria abietivorella

The major components of the sex pheromone of Dioryctria abietivorella (Groté) (Lepidoptera: Pyralidae) were recently identified as (9Z,11E)‐tetradecadien‐1‐yl acetate (9Z,11E‐14:Ac) and a polyunsaturated, long‐chain hydrocarbon (3Z,6Z,9Z,12Z,15Z)‐pentacosapentaene (C25 pentaene). The optimal ratio of these components and the role of potential minor components were not fully determined in the initial short report on the pheromone's identification. We tested different ratios of the two major components loaded into grey halobutyl rubber septum dispensers, placed in sticky traps deployed in conifer breeding arboreta. The optimal ratio of the two components was 200 µg 9Z,11E‐14:Ac to 2000 µg C25 pentaene. (Z)‐9‐Tetradecen‐1‐yl acetate, which had been identified previously in female pheromone gland extracts, and five other potential minor pheromone components, were tested individually as additions to the optimized two‐component lure blend. None of the ternary blends were more attractive than the optimized two‐component blend, at the ratios tested. Two lure adjuvants, a UV stabilizer (Sumisorb 300) and the antioxidant butylated hydroxytoluene, added individually or together, did not affect the attractiveness of the optimized lure blend. The Pherotech diamond sticky trap baited with the optimized lure blend was the most effective trap design among eight types of sticky trap and a bucket style trap that were tested. Traps baited with synthetic lures were as attractive as traps baited with virgin female moths. The optimized two‐component lure blend in the Pherotech diamond trap is recommended for monitoring fir coneworm infestations. The availability of an effective synthetic pheromone opens the possibility for control tactics using mating disruption or attract‐and‐kill techniques.     

Individual comparisons of the levels of (E)-3-methyl-2-hexenoic acid, an axillary odor-related compound, in Japanese

The (E)-3-methyl-2-hexenoic acid (E3M2H), an axillary odor-related compound, is known to occur in Caucasians. The aims of this study were to clarify whether E3M2H contributes to axillary odor in Asians and to quantify and compare individual levels of E3M2H. Quantitative determination of E3M2H was performed by means of gas chromatography-mass spectrometry of sweat extracted from the axillary areas of T-shirts worn for 24 h by Japanese subjects. The amount of E3M2H was 15.9-34.6 nmol/ml in six of 30 subjects. Our method succeeded in quantitative analysis of E3M2H from axillary sweat collected individually; we also showed that E3M2H could be detected in Asians. This is the first report in which the amount of E3M2H in axillary sweat was quantified on an individual basis and compared to reveal individual differences. The results of this study indicate that E3M2H might contribute to axillary malodor in Asians as well as Caucasians.     

Chemical composition of the epicuticular wax from the fruits of Eucalyptus globulus

The chemical composition of the epicuticular wax from the fruits of Eucalyptus globulus was studied by GC-MS before and after alkaline hydrolysis. The wax had two main components, ursolic acid and tritriacontan-16,18-dione, together with several other triterpenic acids. After alkaline hydrolysis, a large increase in the amounts of triterpenic acids and fatty acids (particularly in hexadecanoic acid) was observed, suggesting that these components were present predominantly in esterified forms in the fruit wax. Six compounds were isolated from the fruits by preparative chromatography, and were identified as 8-desmethyleucalyptin, sesamin, tritriacontan-16,18-dione, ursolic acid, 3beta-hydroxyurs-11-en-13beta(28)-olide (ursolic acid lactone) and 3beta,11alpha-dihydroxyurs-12-en-28-oic acid, the latter of which was identified for the first time.