Sex pheromone of the San Jose scale

The sex pheromone of the San Jose scale,Quadraspidiotus perniciosus (Comstock), was isolated from airborne collections on Porapak Q. Two components, present in approximately equal amounts, were identified as (Z)-3,7-dimethyl-2,7-octadien-1-yl propanoate and 3-methylene-7-methyl-7-octen-1-yl propanoate. Greenhouse bioassays and field tests have shown that the compounds are independently attractive to male San Jose scale. These structures are compared with those of other known scale pheromones.     

Synthesis and identification of a third component of the San Jose scale sex pheromone

Two components of the San Jose scale sex pheromone had previously been identified as 7-methyl-3-methylene-7-octen-1-yl propanoate (I) and (Z)-3,7-dimethyl-2,7-octadien-1-yl propanoate (II). An isomer and various homologs have subsequently been synthesized and tested in a greenhouse bioassay. TheE isomer of II (XI) was found to be attractive to male scales. This compound has now been isolated and identified from airborne extracts of virgin female scales. The composition of the natural pheromone was 48.5%, 46.7%, and 4.8% of I, II, and XI, respectively. In field tests in California and New York, synthetic XI was found to be attractive to male scales alone and in combination with I and II, but there was no obvious increase in trap catch when the synthetic isomers were present in the same ratio as in the natural blend. Quadraspidiotus perniciosm (Comstock) (Homoptera: Diaspididae)     

(Z,Z)-4,7-tridecadien-(S)-2-yl acetate: sex pheromone of Douglas-fir cone gall midge,Contarinia oregonensis

Our objectives were to identify and field test the sex pheromone of female Douglas-fir cone gall midge, Contarinia oregonensis (Diptera: Cecidomyiidae). Coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone extract revealed a single compound (A) that elicited responses from male antennae. Hydrogenation of pheromone extract, followed by renewed GC-EAD analysis, revealed a new EAD-active compound with chromatographic characteristics identical to those of tridecan-2-yl acetate on five fused silica columns (DB-5, DB-210, DB-23, SP-1000, and Cyclodex-B). Syntheses, chromatography, and retention index calculations of all possible tridecen-2-yl acetates suggested that the candidate pheromone A was a tridecadien-2-yl acetate with nonconjugated double bonds. Synthetic candidate pheromone component (Z,Z)-4,7-tridecadien-2-yl acetate (Z4Z7) cochromatographed with A on all analytical columns and elicited comparable antennal activity. In GC-EAD analyses that separated the enantiomers (Z,Z)-4,7-tridecadien-(S)-2-yl acetate (2S-Z4Z7) and (Z,Z)-4,7-tridecadien-(R)-2-yl acetate (2R-Z4Z7) with baseline resolution, only 2S-Z4Z7 as a component in a racemic standard or in pheromone extract elicited antennal responses. In Douglas-fir seed orchards, sticky traps baited with 2S-Z4Z7 captured male C. oregonensis, whereas 2R-Z4Z7 was behaviorally benign. Comparable catches of males in traps baited with racemic Z4Z7 (50 g) or virgin female C. oregonensis suggested that synthetic pheromone baits could be developed for monitoring C. oregonensis populations in commercial Douglas-fir seed orchards.     

Simple and economic syntheses of some (Z)-7- and (Z)-9-alkenyl acetates,and of (E,Z)-7,9-dodecadien-1-yl acetate,the sex pheromone of the European grapevine moth,using aleuritic acid as a common starting material

Short syntheses of (Z)-7-dodecen-1-yl acetate, (Z)-7-tetradecen-1-yl acetate, (Z)-9-dodecen-1-yl acetate, and (Z)-9-tetradecen-1-yl acetate from 7-hydroxyheptanal and 9-oxononanoic acid precursors obtained by oxidative cleavage of easily available aleuritic acid are reported. The key step in these syntheses is a stereoselective Wittig reaction between aldehyde and alkyl-phosphonium salt. Wittig-Horner type reaction of 7-hydroxyheptanal and diethyl cyanomethylphosphonate gave the ,-unsaturated nitrile derivative which after protection of the hydroxyl group was reduced to the corresponding aldehyde. Wittig reaction of the latter, followed by acetylation, completed the synthesis of (E,Z)-7,9-dodecadien-1-yl acetate, the sex pheromone of the European grapevine mothLobesia botrana Schiff.     

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.     

Synthesis of (E)-3,9-dimethyl-6-isopropyl-5,8-decadien-1-yl acetate,the sex pheromone of the yellow scale

Synthesis of adefinable mixture of the racemicZ andE isomers of 3,9-dimethyl-6-isopropyl-5,8-decadien-1-yl acetate has been achieved. Comparison of these isomers with the natural pheromone of the yellow scale,Aonidiella citrina (Coquillett) resulted in the identification of the pheromone as (E)-3,9-dimethyl-6-isopropyl-5,8-decadien-1-yl acetate. Aonidiella citrina (Coquillett) (Homoptera: Diaspididae).Contribution No. 69 from the Research Laboratory of Zoecon Corporation.     

Analysis of long-range reproductive behavior of maleDiabrotica virgifera virgifera leconte andD. Barberi Smith and Lawrence to stereoisomers of 8-methyl-2-decyl propanoate under laboratory conditions

Behavioral analysis of male attraction to stereoisomers of 8-methyl-2-decyl propanoate was conducted withDiabrotica virgifera virgifera andD. barberi using a flight tunnel.D. barberi males were attracted to the 2R,8R isomer only, and the response was inhibited by the addition of 2S,8R.D. v. virgifera males were also attracted to the 2R,8R isomer and were neither attracted nor inhibited by any of the other isomers. Males attracted to the lures displayed a series of behaviors characterized by a slow hovering flight upwind towards the odor source. While significant numbers of males of both species landed on the pheromone lure, none attempted copulation, indicating that other cues are necessary to induce this behavior.     

Attraction of pea mothCydia nigricana F. (Lepidoptera: Tortricidae) to female sex pheromone (E,E)-8,10-dodecadien-1-YL acetate,is inhibited by geometric isomersE,Z, Z,E, andZ,Z

Field attraction ofCydia nigricana males to synthetic female sex pheromone (E,E)-8,10-dodecadien-1-yl acetate, formulated on red rubber septa, declined continuously during two weeks. This was due to isomerization of (E,E)-8,10-dodecadien-1-yl acetate: eight days after application of purifiedE,E isomer, the proportion ofE,Z;Z,E; andZ,Z isomers in rubber septa aged in the laboratory was 4%; a 5% addition of any one of these isomers to fresh lures of (E,E)-8,10-dodecadien-1-yl acetate significantly reduced male attraction. Stereospecific syntheses of (E,Z)-, (Z,E)-, and (Z,Z)-8,10-dodecadien-1-yl acetate are described. The pheromone gland ofCydia nigricana contains 0.8 ng/female of (E,E)-8,10-dodecadien-1-yl acetate, accompanied by three monounsaturated acetates, (E)-9-dodecen-1-yl acetate, (Z)-5-tetradecen-1-yl acetate, and (Z)-7-tetradecen-1-yl acetate (0.1 ng/female each). These compounds did not augment male trap catch when added to (E,E)-8,10-dodecadien-1-yl acetate.     

Major Sex Pheromone Components of the Australian Gum Leaf Skeletonizer Uraba lugens: (10E,12Z)-Hexadecadien-1-yl Acetate and (10E,12Z)-Hexadecadien-1-ol

Two sex pheromone components of the gum leaf skeletonizer, Uraba lugens (Lepidoptera: Nolidae), recently established in New Zealand, were identified. Gas chromatography (GC) electroantennographic detection analyses of female pheromone gland extracts gave three compounds that consistently elicited antennal responses. Chemical analyses, using GC and GC-mass spectrometry, in conjunction with 4-methyl-1,2,4-triazoline-3,5-dione and dimethyldisulfide derivatizations, identified these compounds as (10E,12Z)-hexadecadien-1-yl acetate (E10,Z12-16:Ac), (10E,12Z)-hexadecadien-1-ol (E10,Z12-16:OH), and (Z)-11-hexadecen-1-yl acetate (Z11-16:Ac). A trapping trial in Queensland, Australia, in 2002, indicated that a blend of the two major components E10,Z12-16:Ac and E10,Z12-16:OH could attract gum leaf skeletonizer males. In the same trial, E10,Z12-16:Ac alone trapped large numbers of an unidentified nolid, Nola spp. Further trials in Auckland, New Zealand established that these two components were sufficient and necessary for trap catch of males; adding minor gland components, (10E,12E)-hexadecadien-1-yl acetate (E10,E12-16:Ac), Z11-16:Ac, or octadecan-1-ol (18:OH), to the two-component lure did not result in increased trap catches. Behavioral observations and gland analyses of the Auckland population revealed that female moths begin calling soon after emergence, with peak calling and pheromone production occurring 7 hr into the scotophase. Analysis of gland extract at two-hourly intervals during the first activity period showed that the ratio of E10,Z12-16:Ac to E10,Z12-16:OH (mean of 86: 14, respectively) and pheromone titer were fairly constant. No qualitative or quantitative differences in pheromone components were detected between gland extracts from Tasmanian univoltine and Auckland bivoltine populations of U. lugens.     

Methylbutynol effectively replaces methylbutenol,a pheromone component ofIps typographus (L.) (Coleoptera: Scolytidae)

In field experiments in Sweden, the constituent 2-methyl-3-buten-2-ol of the aggregation pheromone of the spruce bark bettleIps typographus (L.) was effectively replaced by 2-methyl-3-butyn-2-ol.     

Sex pheromone of the black cutworm moth,Agrotis ipsilon

(Z)-7-Dodecen-1-yl acetate (I) and (Z)-9-tetradecen-1-yl acetate (II) have been identified as sex pheromone components of the black cutworm moth,Agrotis ipsilon (Hufnagel). They are emitted by the female in approximately a 51 ratio. Differential saturation studies with male antennae suggest that there are two different acceptor sites for the two pheromone components. The most effective lures found in field trapping tests were 30 g of I plus 10 g of II on a rubber septum, and a 31 mixture of I and II dispensed from a 0.2-mm-ID glass capillary tube sealed at one end.Lepidoptera: Noctuidae.Supported at Geneva, in part by the Rockefeller Foundation and by National Science Foundation Grant GB-38020; and at Wooster, in part by Environmental Protection Agency Grant EPA R802547 and by USDA Cooperative State Research Service Grant 316-15-99. Approved by the Director of the New York State Agricultural Experiment Station for publication as Journal Paper3186. Approved for publication as Journal Article113-78 of the Ohio Agricultural Research and Development Center, Wooster, OH 44691.     

(Z)-7-Tricosene and Monounsaturated Ketones as Sex Pheromone Components of the Australian Guava Moth Coscinoptycha improbana: Identification, Field Trapping, and Phenology

Pheromone gland extracts of the Australian guava moth Coscinoptycha improbana (Lepidoptera: Carposinidae), contained four compounds that elicited responses from male moth antennae in gas chromatography-electroantennogram detection (GC-EAD) analyses. These were identified by GC-mass spectrometry as (Z)-7-tricosene (Z7-23Hy), (Z)-7-octadecen-11-one (Z7-11-one-18Hy), (Z)-7-nonadecen-11-one (Z7-11-one-19Hy), and (Z)-7-tricosen-11-one (Z7-11-one-23Hy) at a ratio of 65:23.5:1.5:10, respectively. Z7-23Hy, Z7-11-one-18Hy, and Z7-11-one-23Hy have not previously been reported as lepidopteran sex pheromone components. Z7-11-one-18Hy was active as a single component, and was synergized by Z7-11-one-23Hy but not Z7-11-one-19Hy, although the latter compound was weakly attractive as a single component. Addition of Z7-23Hy further increased attraction. The amount of the major pheromone component, Z7-11-one-18Hy in female pheromone gland extracts was estimated to be 16.4 ng/female (N = 8). Phenological data gathered over a 12-mo period in 2002 and 2003 using the binary blend indicated that moths are active throughout the year. The pheromone has already been employed to monitor the spread of C. improbana in New Zealand and detect its presence in Queensland, Australia.     

Response of northern corn rootworm,Diabrotica barberi Smith and Lawrence,to stereoisomers of 8-methyl-2-decyl propanoate

The four stereoisomers of 8-methyl-2-decyl propanoate were tested in South Dakota for attractiveness to the northern corn rootworm,Diabrotica barberi Smith and Lawrence (NCR). Only the 2R,8R configuration was attractive to the NCR. Inhibition of the NCR response to 2R,8R occurred when either the 2S,8R or 2S,8S isomers were components of the pheromone source. The 2R,8S configuration elicited no behavioral activity in the NCR.Coleoptera: ChrysomelidaeMention of a commercial or proprietary product does not constitute an endorsement by the USDA.Deceased.     

Sex pheromone components of the oblique-banded leafroller,Choristoneura rosaceana in the Okanagan Valley of British Columbia

(Z)-11-Tetradecen-1-yl acetate, (E)-11-tetradecen-1-yl acetate, and (Z)-11-tetradecen-1-ol were previously reported as the sex pheromone in New York strains of the oblique-banded leafroller,Choristoneura rosaceana (Harris), and (E)-11-tetradecen-1-ol was tentatively identified in female tip extracts. For Okanagan Valley strains ofC. rosaceana, an additional component, (Z)-11-tetradecenal, was identified from female tip extracts by split-less capillary gas-liquid chromatography and mass spectroscopy and was strongly stimulatory in electroantennogram studies. In field tests, 3 mg of 96.521.5 (Z)-11-tetradecen-1-yl acetate, (E)-11-tetradecen-1-yl acetate, and (Z)-11-tetradecen-1-ol (containing approx. 1%E isomer) was not as attractive as female-baited traps, and significant numbers of European leafrollerArchips rosanus L. were attracted. The above blend with 1% (Z)-11-tetradecenal added was significantly more attractive than traps baited with femaleC. rosaceana, butA. rosanus males were still attracted. Increased percentages of (Z)-11-tetradecenal up to 4% caused increased catches ofC. rosaceana and decreased catches ofA. rosanus. Low amounts of (E)-11-tetradecen-1-ol and (E)-11-tetradecenal male also contribute to increased specificity of the synthetic pheromone blend toC. rosaceana.Lepidoptera: Tortricidae.Contribution No. 638, Agriculture Canada, Research Station, Summerland, British Columbia, Canada.     

(7<Emphasis Type="Italic">Z</Emphasis>,9<Emphasis Type="Italic">E</Emphasis>)-2-Methyl-7,9-Octadecadiene: A Sex Pheromone Component of <Emphasis Type="Italic">Lymantria Bantaizana</Emphasis>

Our objective was to identify the sex pheromone of Lymantria bantaizana (Lepidoptera: Lymantriidae) whose larvae feed exclusively on walnut, Juglans spp., in China, and Japan. Coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone gland extracts revealed a single EAD-active component. Retention index calculations of this compound on four GC columns suggested that it was a methyl-branched octadecadiene with conjugated double bonds. In GC-EAD analyses of 2-methyloctadecenes, (Z)-2-methyl-7-octadecene and (E)-2-methyl-7-octadecene elicited the strongest antennal responses, suggesting that the double bond positions were at C7 and C9. In comparative GC-EAD analyses of pheromone gland extract and stereoselectively synthesized isomers (E,E; E,Z; Z,E; Z,Z) of 2-methyl-7,9-octadecadiene, the (E,Z)- and (Z,E)-isomer had retention times identical to that of the candidate pheromone, but only the latter isomer elicited strong EAD activity. Results of field experiments in Japan substantiated that (7Z,9E)-2-methyl-7,9-octadecadiene is the L. bantaizana sex pheromone, a compound previously unknown in the Lepidoptera. Detection surveys in North America for exotic Eurasian forest defoliators could include traps baited with the L. bantaizana pheromone.     

Replacement of carcinogenic alkylating agent ethylene oxide in the synthesis of (Z)-3-dodecen-1-YL (E)-2-butenoate,sex pheromone of sweet-potato weevil,Cylas formicarius elegantulus (summers) andCylas formicarius formicarius (F.)

An alternative synthesis of (Z)-3-dodecen-1-y1 (E)-2-butenoate without use of carcinogenic ethylene oxide and HMPA is described. By coupling of the tetrahydropyranyl (THP) ether of 3-butyn-1-ol with 1-bromooctane with sodamide in liquid ammonia, 12-(2-tetrahydropyranyloxy)-9-dodecyne was obtained; subsequent hydrolysis and semihydrogenation afforded (Z)-3-dodecen-1-ol. The alcohol was then reacted with crotonyl chloride to give the desired crotonate with a total yield of 29.8%. Males of sweet-potato weevil,Cylas formicarius were strongly attracted to the synthetic sex pheromone. The attraction from the dispenser of polyethylene tube was better than the attraction from the dispenser of rubber septum in the field.     

Identification of a female-produced sex pheromone of the western corn rootworm

A sex pheromone has been isolated and identified from virgin females of the western corn rootworm (WCR),Diabrotica virgifera virgifera LeConte. The synthesized compound, racemic 8-methyl-2-decanol propanoate, was equal in attraction to the natural pheromone when tested in the field as a trap bait against three taxa ofDiabrotica known to respond to pheromone extracts from female WCR. Five taxa (D. virgifera virgifera; D. virgifera zeae Krysan and Smith, Mexican corn rootworm;D. longicornis barberi Smith and Lawrence, northern corn rootworm;D. longicornis longicornis (Say); andD. porracea Harold) were attracted to traps baited with 8-methyl-2-decanol propanoate. The response of male northern corn rootworms (NCR) in the field peaked at a relatively low concentration of 8-methyl-2-decanol propanoate and then was severely reduced at the higher concentrations tested. Conversely, the response of male WCR in the field continued to increase up to the highest dose tested.     

Female sex pheromone of the Yunnan pine caterpillar moth Dendrolimus houi: first (E,Z)-isomers in pheromone components of Dendrolimus spp

The Yunnan pine caterpillar Dendrolimus houi Lajonquière is a serious defoliator of coniferous forests in southwestern China. Gas chromatography–electroantennography (GC–EAG) analyses of extracts of female sex pheromone glands of D. houi moths revealed the presence of three compounds eliciting antennal responses. These were identified as (5E,7Z)-5,7-dodecadien-1-ol (E5,Z7-12:OH), (5E,7Z)-5,7-dodecadien-1-yl acetate (E5,Z7-12:OAc), and (5E,7Z)-5,7-dodecadienal (E5,Z7-12:Ald) by comparison of their GC retention indices, mass spectra, and EAG activities with those of synthetic standards. Average amounts of E5,Z7-12:OH, E5,Z7-12:OAc, and E5,Z7-12:Ald per calling virgin D. houi female were 14.7 ± 12.9 ng (± SD), 5.8 ± 5.4 ng, and 0.8 ± 1.4 ng, respectively, in a ratio of 100:39.7:5.6. These three components were also collected from the headspace of calling virgin female moths by solid-phase microextraction (SPME). In addition, trace quantities of (Z)-5-dodecen-1-ol (Z5-12:OH), (5Z,7E)-5,7-dodecadien-1-ol (Z5,E7-12:OH), (5E,7E)-5,7-dodecadien-1-ol (E5,E7-12:OH), (5Z,7E)-5,7-dodecadien-1-yl acetate (Z5,E7-12:OAc), (5Z,7Z)-5,7-dodecadien-1-yl acetate (Z5,Z7-12:OAc), and (5E,7E)-5,7-dodecadien-1-yl acetate (E5,E7-12:OAc) were tentatively identified in female pheromone gland extracts by selected ion monitoring GC-MS. Field trapping experiments showed that E5,Z7-12:OH, E5,Z7-12:OAc, and E5,Z7-12:Ald were essential for attraction of male D. houi moths. Traps baited with a 20:1:1 blend (alcohol/acetate/aldehyde) loaded on gray rubber septa were as effective as traps baited with virgin female moths. The optimum ratio of acetate to aldehyde was 1:1, and this ratio was more critical than the ratio of either compound to the alcohol. This represents the first example of (E,Z)-isomers in pheromone blends of Dendrolimus species.     

Identification of a Sex Pheromone Component of Pseudococcus cryptus

A sex pheromone component of Pseudococcus cryptus has been isolated and identified. The crude pheromone extract obtained by airborne collection was fractionated by liquid chromatography (LC) on Florisil, and further purified by high performance liquid chromatography and preparative Gas Chromatography (GC). The pheromone component was shown to be an ester, the alcohol part of which was identical to the known alcohol moiety of the pheromone of Planococcus citri. The chemical structure was determined to be 3-isopropenyl-2,2-dimethylcyclobutylmethyl 3-methyl-3-butenoate by MS and ¹H NMR analyses. The absolute configuration of the pheromone was assigned as (1R,3R) by comparison of the retention time of the alcohol derived from the P. cryptus pheromone with those of the alcohol derived from P. citri pheromone, and a synthetic sample of alcohol enriched in the (1R,3R)-enantiomer, using a chiral GC stationary phase. The structure of the pheromone was confirmed by synthesis, and by bioassays in a glasshouse.     

Semiochemicals from bark beetles: New results,remarks, and reflections

A brief survey is given about recent results in the identification of semiochemicals in bark beetles: Males ofIps sexdentatus (Boern.), stressed by the attack on resinous trees produce large amounts of 3(S)-1-methyl-5-(1-hydroxyl-1-methylethyl)-cyclohexa-1,3-diene. The compound appears to be derived from ³-carene and acts as a repellent. Males ofIps typographus (L.), stressed through the attack on unsuitable host material release 3-methyl-7-methylene-1,3(E), 8-nonatriene, which seems to act as a repellent. The odor bouquet of three species ofPityogenes is described. The occurrence of (+)-grandisol and other compounds related to weevil pheromones points to a close relation between Scolytidae and Curculionidae. Females ofDendroctonus simplex (Le Conte) use (–)-frontalin as the main pheromone. 6-Methyl-6-hepten-2-one, a minor component among the volatile compounds released by the females, is regarded as a possible precursor of frontalin. Similarly, (2R,5S)-2(1-hydroxyl-1-methylethyl)-5-methyltetrahydrofuran, pityol, a pheromone ofPityophthorus spp., is regarded to at least share a common biogenetic precursor with 6-methyl-5-hepten-2-ol, sulcatol. A new bicylic acetal, 2-ethyl-1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane, is described as an aggregation pheromone of the beech bark beetle,Taphrorychus bicolor (Herbst). Structural relationships between bark beetle pheromones and plant volatiles are discussed.