Trapping social wasps (Hymenoptera: Vespidae) with acetic acid and saturated short chain alcohols.

Nineteen compounds were evaluated in combination with a solution of acetic acid as baits for trapping the German yellowjacket, Vespula germanica (F.), the western yellowjacket Vespula pensylvanica (Sausssure), and the golden paper wasp Polistes aurifer Saussure. Compounds with three to six carbon chains or branched chains and with a hydroxy functional group were selected for testing based on their similarity to isobutanol. They were compared with isobutanol with acetic acid, which is a known wasp attractant. None of the compounds tested were superior to isobutanol when presented with acetic acid as a lure for these species of wasps. However, traps baited with either the S-(-)- or the racemic mixture of 2-methyl-1-butanol in combination with acetic acid captured similar numbers of both species of yellowjackets, compared with isobutanol with acetic acid. Polistes aurifer responded strongly to the S-(-)-enantiomer and to the racemic mixture of 2-methyl-1-butanol with acetic acid and not to the R-(+)-enantiomer with acetic acid.

Efficacy of nonpheromone communication disruptants of codling moth (Cydia pomonella): Effect of pheromone isomers and of distance between calling females and dispensers.

Field tests comparing the ability of codlemone, (E,E)-8,10-dodecadien-1-ol, and isomers of codlemone to disrupt pheromonal communication of codling moth were carried out. In a pear orchard, four nonisomerizing, gray septa dispensers were placed in the upper canopy of each tree containing a trap baited with 10 virgin female codling moths. The dispensers were at trap height and 70 cm from the edge of each trap. Trap catches of released male codling moths in three test areas were compared simultaneously when trees in each of the test areas contained unbaited dispensers, dispensers with 1 mg of codlemone containing 1% isomers, and dispensers with 1 mg of a test communication disruptant. When the test disruptant was an equilibrium mixture of codlemone and its isomers (61% codlemone, 39% isomers), the percent communication disruption was 86.8% compared to 68.7% for codlemone (P < 0.001). When the disruptant was (E,Z)-8,10-dodecadien-1-ol (94%EZ, 3%EE), the percentage disruption was 86.4% compared to 62.7% for codlemone (P < 0.002). These results show that the previously reported superior disruptant potency (relative to codlemone) of compositions containing codlemone with a high percentage of isomers was not a result of the proximity of the dispensers to the traps. The percent disruption of compositions of codlemone with 10 and 20% isomers was also determined. A plot of percentage disruption versus logarithm of percentage of nonpheromone isomers in the mixture from 1% to 97% gave a straight line withR (2)=0.93.

Codling moth,Cydia pomonella, (Lepidoptera: Tortricidae): Is its sex pheromone multicomponent?

When the nine identified components in the effluvium of calling female codling moths were compared to pure synthetic (E,E)-8,10-dodecadien-1-ol in flight-tunnel tests, equal responses were obtained over a concentration range of 300-fold. When synthetic (E,E)-8,10-dodecadien-1-ol was compared to extract of female sex pheromone glands by a male wing-flutter bioassay, or in flight-tunnel tests, equal responses were obtained over a concentration range of 1000-fold. The sum total of these and previous studies indicate that the codling moth sex pheromone consists of only one component.

Codling moth (Cydia pomonella): Disruptants of sex pheromonal communication.

In a small section of an apple orchard, six traps were placed each in control and test areas and baited with live virgin female codling moths. Gray elastomer septa were used to dispense communication disruptants around the traps. Dyed male codling moths were released in control and test areas, and the numbers of males captured in control and test traps were compared. In 1991, linear regression curves of percent communication disruption versus logarithm of dose were obtained for three compositions: (E,E)-8,10-dodecadien-1-ol, codlemone (1); codlemone + dodecan-1-ol + tetradecan-1-ol (2); and an equilibrium mixture of the four isomers of 8,10-dodecadien-1-ol (30, (61%EE, 14%ZE, 20%EZ, and 5%ZZ). All three regressions gaver (2) values greater than 0.90. At the 95% confidence limits, slopes and intercepts of compositions 1 and 2 were equivalent, and different from that of composition 3, which produced the greatest percentages of disruption at all doses. In 1992, five treatments were compared at a single dose: 1, 3, none (4), (Z,E)-8,10-dodecadien-1-ol (5), (E,Z)-8,10-dodecadien-1-ol (6). Compositions 5 and 6 gave the greatest and similar percentages of disruption and were different from codlemone (1) and 4 (95% confidence), but not from composition 3. Communication disruption produced by composition 3 was greater than (codlemone), which was greater than 4.

Sex pheromone of cranberry fruitworm,Acrobasis vaccinii riley (Lepidoptera: Pyralidae).

The following compounds and (approximate ratios) were identified in sex pheromone gland extracts of femaleAcrobasis vaccinii Riley by comparison of gas chromatography-mass spectrometric traces with those of synthetic standards: (E,Z)-, (Z,E)-, (Z,Z), and (E,E)-8, 10-pentadecadien-l-ol acetates (100:1:2:12), a dodecen-l-ol acetate (8), (Z)-8-, (Z)-9-, and (E)-9-pentadecen-l-ol acetates (3:23:4), two heptadecen-l-ol acetates (4:4), tetradecyl, pentadecyl, hexadecyl, and heptadecyl acetates (3:15:10:8), dodecan-l-ol (6), tetradecan-l-ol (5), and hexadecan-l-ol (23). The amount of (E,Z)-8, 10-pentadecadien-l-ol acetate (E8,Z10-15:Ac) in the extract was about 0.5 ng/female. Electroantennographic analysis of gas chromatographic fractions of female sex pheromone gland extract showed that the fraction containingE8,Z10-15:Ac elicited the greatest response. Alone,E8,Z10-15:Ac failed to elicit upwind flight of males in flight-tunnel tests, and traps baited with it did not catch males in field experiments. WhenE8,Z10-15:Ac was combined with (E)-9-pentadecen-l-ol acetate (100:4), male upwind flight response in flight-tunnel tests was equivalent to those obtained with extract of female sex pheromone glands (synthetic, 62%; natural, 51%), but the percent of males flying upwind that contacted the source was lower (synthetic, 47%; natural, 88%). The lower percent of source contact elicited by the synthetic pheromone could be a result of the difference in isomer ratios of 8,10-15:Ac in the natural and synthetic pheromone or could indicate that the synthetic pheromone is incomplete. Traps baited with the 100:4 combination caught large numbers of males in field experiments.

Sugar beet crown borer,Hulstia undulatella (Clemens) 1: Identification and field tests of female sex pheromone gland components.

Electroantennogram profiles of saturated and monounsaturated 12-, 14-, and 16-carbon acetates, and 12- and 14-carbon alcohols implicated (Z)-9-tetradecen-1-ol acetate (Z9-14: Ac) as a component of the female sex pheromone ofHulstia undulatella (Clemens). Gas chromatography-mass spectrometric analysis of extract of the female sex pheromone glands showed the presence of Z9-14:Ac (8.5 ng/female), (Z)-9-tetradecen-1-ol (Z9-14:OH), and (Z)-11-hexadecen-1-ol acetate (Z11-16:Ac) in a ratio of 100∶4∶21, respectively. In tests in sugar beet fields, Z9-14:Ac alone produced some trap catch. Addition of Z9-14: OH did not increase catch while addition of Z11-16:Ac eliminated catch, but addition of both Z9-14:OH and Z11-16: Ac increased catch sevenfold. A combination of Z9-14: OH and Z11-16: Ac without Z9-14: Ac did not produce trap catch. A lure of 200 µg Z9-14:Ac+16 µg Z9-14:OH+42 µg Z11-16:Ac is suggested for use in monitoring traps.

Response of male codling moths (Cydia pomonella) to components of conspecific female sex pheromone glands in flight tunnel tests.

In flight tunnel tests, the percentages of oriented upwind flights of male codling moths culminating in contacting a source of different compositions of female sex pheromone gland components were determined over a dosage range of 0.1-100,000Μg. The following compositions were tested: (1) (E,E)-8,10-dodecadien-1-ol of 99.7% isomeric purity; (2) 1 + dodecanl-ol + tetradecan-1-ol; (3) 2 + decan-1-ol + (E)-9-dodecen-1-ol; and (4) an equilibrium mixture of 8,10-dodecadien-1-ol isomers (61%EE, 5%ZZ, 14%ZE, and 20%EZ). The ratios of the components in compositions 2 and 3 were chosen to produce vapor ratios equal to the natural ratios found in the female effluvium by Arn and coworkers. As the dose of composition 1 was increased from 0.1 to 10Μg, response increased from 0 to about 80% and then was approximately constant from 10 to 300Μg. Over the range 0.1-300Μg, the percentage of males contacting the septum was virtually the same as the percentage flying upwind. From 300 to 100,000Μg, the percentage of males flying upwind and contacting the source steadily decreased from about 80 to 0%. The male responses to compositions 2 and 3 were virtually identical to the response to 1. These results indicate, contrary to published reports, that dodecan-1-ol and tetradecan-1-ol in combination with 1 do not increase the responses of the behavioral modes determining degree of attractancy and disruption of sexual communication over that of 1 alone. These results also show that decan-1-ol and (E)-9-dodecen-1-ol do not enhance response in the five-component mixture. The response to composition 4 increased from 0% at a dose of 0.3Μg to 26% at a dose of 30Μg and then decreased to 0% at a dose of 3000Μg. Thus, the inhibiting effect of the isomers on response was greater at the higher doses.

Performance characteristics of a commercial controlled-release dispenser of sex pheromone for control of codling moth (Cydia pomonella) by mating disruption.

Performance characteristics of polyethylene tube dispensers containing a mixture of (E,E)-8,10-dodecadien-1-ol (1), dodecan-1-ol (2), and tetradecan-1-ol (3) were evaluated for suitability as a mating disruptant for codling moth control. The rate of loss of pheromone component from a dispenser at any time was found to be described by the equation: -dP/dt=(k 1 k 2 +k d)P whereP is the amount of pheromone component in the dispenser well;t is time;k 1 is the ratio of the amount dissolved in the dispenser wall to the amount in the dispenser well;k 1 is the ratio of the evaporation rate to the amount dissolved in the dispenser wall;k d is the rate constant for chemical decomposition. The evaporation rate,E, of a pheromone component at any time was given by:E=k 1 k 2 P For all three components during the first three weeks,k 1 decreased from ca. 0.25 to ca. 0.10 and was approximately constant thereafter. The decrease ofk 1 with time may have been caused by weather-induced cross-linking of the polyethylene. Over timek 2 was constant and was 1.27 ± 0.26 × 10(-3)/hr for1, 1.96 ± 0.33 × 10su-3/hr for 2, and 0.31± 0.05 × 10(-3)/hr for 3. Thek 2 was zero for2 and3 and 6.96 × 10(-4) for1. After 150 days in an orchard in 1991, 95% of1 was lost from the dispensers (61% of the loss was by chemical decomposition and 39% by evaporation). The heat summation units in a Yakima valley orchard during 1991 were 4.7% above the average for the 1980-1991 period, while during 1990 they were the highest for this period (26% above average). After the first three weeks of dispenser aging, the regression line half-lives for1 for 1990 and 1991 were 31.0 and 35.1 days, respectively. The difference in temperature between 1990 and 1991 did not affect the half-life of1 very much because so much of the loss was from photochemically induced decomposition. Based on an estimate of the required minimum evaporation rate for mating disruption of 2 mg/ha-hr and a half-life of 35 days for1, 2345 dispensers/ha would be required for one application per season; 944 dispensers/ha for two applications per season; and 734 dispensers/ha for three applications per season. If a different emission rate of1 is required for reliable mating disruption, then the number of dispensers required would be changed proportionately.

Mint root borer,Fumibotys fumalis (Guenee): Identification and field tests of female sex pheromone gland components.

Compounds identified in sex pheromone gland extracts of femaleFumibotys fumalis (Guenee) consisted of (E,E)-10,12-tetradecadienyi acetate, (Z)-11-tetradecenyl acetate, (E)-11-tetradecenyl acetate, and (Z)-9-tetradecenyl acetate in a ratio of 100:18: 8:4, respectively. The compounds were identified by electroantennographic, gas Chromatographic, mass spectrometric, and chemical derivatization procedures. In mint fields synthetic components in gray elastomeric septa at ratios found in the sex pheromone gland and at doses of 3 or 10 mg of the diene produced trap catch comparable to traps baited with three females.

Sex pheromone of hickory shuckwormCydia caryana Development of an effective field Lure.

Extracts of the sex pheromone glands of femaleCydia caryana were evaluated by electroantennography and gas chromatography-mass spectrometry. These studies suggested the following compounds were potential sex pheromone components: (Z)-8- and/or (E)-9-dodecenyl acetate (50 pg/female), dodecyl acetate (40 pg/female), and (E, E)-8,10-dodecadienyl acetate (25 pg/female). In field tests only the diene produced trap catch, and when the other components were added to the diene, trap catch was not increased. When the diene was formulated in red natural rubber septa, only transient and low catches were obtained, but when gray halobutyl isoprene elastomeric septa were used, high and consistent catches were obtained for eight weeks. Catches depended on the ratio of (E, E)-8,10 to (E, Z)-8,10 isomers. High catches were obtained for anEE toEZ ratio of 100 ∶ 0.6, and insignificant catches were obtained when the ratio was 100 ∶ 3. Equivalent catches were obtained for dosages of 50, 100, and 200 µg/septum.

Apple ermine moth,Yponomeuta malinellus Zeller Two components of female sex pheromone gland highly effective in field trapping tests.

When electroantennographic responses of maleYponomeuta malinellus Zeller to model compounds were determined at dosages of 0.3-30 ng, the strongest responses were obtained from (Z)-9-dodecen-1-ol acetate (Z9-12∶Ac). Also, strong responses were obtained from (Z)-11-tetradecenal (Z11-14∶A1) and (Z)-11-tetradecen-1-ol (Zl1-14∶OH). At a dosage of 0.3 ng,Z11-14∶A1 produced a stronger response thanZ11-14∶OH, while at a dosage of 30 ng,Z11-14∶OH andZ11-14∶A1 produced equal responses. Gas chromatographic and mass spectral analysis of extracts of female sex pheromone glands showed the presence ofZ9-12∶Ac, tetradecan-1-ol (14∶OH), (E)-11-tetradecen-1-ol (E11-14∶OH),Z11-14∶OH, hexadecan-1-ol, and hexadecan-1-ol acetate in a ratio of 0.6∶200∶37∶100∶140∶35. In field tests,Z9-12∶Ac andZ11-14∶OH together were required for trap catch, and addition ofZ11-14∶A1,E11-14∶OH, 14∶OH, or (Z)-11-tetradecen-1-ol acetate did not increase catch. Ratios in rubber septa of 0.5∶99.5 to 1.5∶98.5 (Z9-12∶ Ac/Z11-14∶OH) captured the most males and captures were statistically equivalent for dosages of 10-1000 µg/rubber septum. Traps baited with the synthetic lure produced better catches than those baited with females.

Insect sex pheromones : Effect of temperature on evaporation rates of acetates from rubber septa.

The half-lives (t 1/2) for evaporative loss ofn-alkyl andn-alkenyl acetates from rubber septa were determined at temperatures varying from 15 to 35 °C. The changes int 1/2 with temperature gave high correlations with the equation, Int 1/2 = ΔH/RT+y o where ΔΔH is the heat of vaporization,R is the gas constant,T is the absolute temperature, andy o is a constant. Half-lives changed dramatically with temperature and the degree of change with temperature increased with increasing molecular weight. For mixtures, component ratios changed with temperature, but the degree was modest. At 20 °C there was a 7.5-fold ratio oft 1/2 between members of the homologousn-alkyl orn-alkenyl acetates differing by two carbon atoms. The large change int 1/2 with temperature and with number of carbon atoms is a consequence of the thermodynamic relationships and the temperature range of pheromone usage. Therefore, a similar degree of change inf 1/2 with temperature and number of carbon atoms will apply to other formulations of the same type (those in which the rate of evaporation is first order). The values oft 1/2 at 20 °C mainly agreed very well with those reported previously at room temperature. However, our previously reported values for pentadecyl and hexadecyl acetate were revised. Half-lives were shown to depend on the vapor pressure of a compound in the formulation substrate, but not on the vapor pressure of the pure compound.

Blackheaded fireworm: Laboratory and field studies of its sex pheromone.

Electroantennogram (EAG) responses of maleRhopobota naevana (Hübner), the blackheaded fireworm, to all of the monoene straightchain 12- and 14-carbon alcohols and acetates implicated (Z)-11-tetradecenl-1-ol (Z11-14∶OH) and its acetate (Z11-14∶Ac) as sex pheromone components.Z11-14∶Ac produced the strongest EAG response of all compounds tested. Gas chromatography-mass spectrometry (GC-MS) analysis of extract of female sex pheromone glands (SPG) confirmed the presence ofZ11-14∶OH (125 pg/female) andZ11-14∶Ac (600 pg/female) (all other monoenes had different retention times). In field tests, traps baited withZ11-14∶OH alone captured males, but traps baited withZ11-14∶Ac alone did not. Traps baited with a combination ofZ11-14∶OH andZ11-14∶Ac in various ratios did not produce better trap catches thanZ11-14∶OH alone. (Z)-9-Dodecen-1-ol acetate (Z9-12∶Ac), reported by others to be a field attractant, did not produce trap catch in our tests, but in combination withZ11-14∶ OH (98∶2 in septa corresponding to 95:5 in vapor,Z11-14∶OH toZ9-12∶AC) produced a sevenfold increase in catch overZ11-14∶OH alone. IfZ9-12∶AC had been present in extract of SPG at 2-5% ofZ11-14∶OH, it would not have been detected in our GC-MS experiment.

Sabulodes caberata guenée (Lepidoptera: Geometridae) : Components of its sex pheromone gland.

A 6,9-nonadecadiene, (Z)-9-nonadecene, andn-nonadecane were identified in extracts of sex pheromone glands of femaleSabulodes caberata Guenée. Potential pheromonal activity of gland components was assessed by electroantennogram measurements of gas-chromatographic fractions of abdominal tip extracts. Chemical identification was based on gas chromatography and mass spectrometry of parent compounds, hydrogenation products, ozonolysis products, dimethyl disulfide adducts, and synthesis. The monoene was synthesized via coupling of alkyl and acetylenic intermediates. (Z,Z)-6,9-Nonadecadiene (Z6,Z9-19∶H) was synthesized from methyl linoleate via chain lengthening. SyntheticZ6,Z9-19∶H had the same retention times on polar and nonpolar capillary gas-chromatographic columns as the 6,9-nonadecadiene from the sex pheromone glands. In field testsZ6,Z9-19:H alone produced trap catch of maleS. caberata and addition of (Z)-9-nonadecene orn-nonadecane had no effect on trap catch.

Western avocado leafroller,Amorbia cuneana (Walsingham), (Lepidoptera: Tortricidae) : Discovery of populations utilizing different ratios of sex pheromone components.

The most effective lure for maleAmorbia cuneana (Walsingham) in Orange, Ventura, and Riverside counties of California was previously found to be a 1∶1 ratio of (E,E)-10,12- and (E,Z)-10,12-tetradecadien-1-ol acetates. In subsequent field tests in San Diego and Santa Barbara counties, this lure was ineffective. Analysis of sex pheromone glands (SPG) of femaleA. cuneana from these two counties showed theEE:EZ ratio to be about 1∶9 and synthetic lures of this composition were highly attractive in these areas. Analysis of the SPG of a number of females from both areas showed that there were three population types: two in the low ratio areas possessed 37 and 58%EZ, and the third in the high ratio areas possessed 89%EZ.

Filbertworm sex pheromone : Identification and field tests of (E,E)- and (E,Z)-8,10-dodecadien-1-ol acetates.

(E,E)- and (E,Z)-8,10-Dodecadien-1-ol acetates were identified in a 1∶4.3 ratio in the extract of abdominal tips of female filbert-worm moths,Melissopus latiferreanus (Walsingham). The identifications were based on electroantennogram (EAG) analysis, gas chromatography, mass spectrometry, ozonolysis, and synthesis. TheE,Z isomer produced the stronger EAG response. In the field tests of various ratios ofE,E∶E,Z, the ratio found in the extract captured the most males. The pureE,E isomer initially was not attractive by itself (<0.1%E,Z) but became attractive after a few days, presumably because of isomerization. TheE, Z isomer (<0.1%E,E) was attractive initially, but this compound might have isomerized faster than theE,E isomer. A study of the isomerization showed that regardless of the initial mixture of 8,10-dodecadien-1-ol acetate isomers, almost complete equilibration existed after one month. The equilibrium mixture consisted of 9%Z8,E10, 65%E8,E10, 23%E8,Z10, and 3%Z8,Z10. Concentrations in rubber septa (1∶4 ratio ofE,E toE,Z) of 0.03-3.0 mg/septum produced equivalent trap catches.

Insect sex pheromones: Determination of half-lives from formulations by collection of emitted vapor.

A new method for determining half-lives for the evaporation of sex pheromones from formulations has been developed. A previously unexploited mathematical relationship makes possible the determination of half-lives of over 1000 days by collecting evaporated pheromone for 1-4 hr and measuring the amount collected and the amount left in the formulation. Purified nitrogen flows over the test material and the evaporated pheromone is qualitatively collected on an adsorbent of 80-100 mesh silica gel silanized with octadecyltrichlorosilane. Quantitation is by gas chromatography. Quantitative mass balance was achieved and half-lives determined by this new method are in agreement with half-lives previously determined by measuring the amount of pheromone left in septa after a sequence of time intervals. Previously undetermined half-lives for acetates and alcohols are reported.

Sex pheromone of the avocado pest,Amorbia cuneana (Walsingham) (Lepidoptera: Tortricidae) : Structure and synthesis.

The major volatile components in the extract of the female sex pheromone gland ofAmorbia cuneana consisted of (E,E)- and (E,Z)-10,12-tetradecadien-1-ol acetates. The identification was based on electroantennogram bioassay of gas Chromatographic effluent from sex pheromone gland extract, relative retention times on polar and nonpolar gas chromatographic columns, chemical degradation (ozonolysis, saponification), mass spectrometry, chemical synthetic methods, and field tests. Based on mass spectrometry and retention times by capillary gas chromatography, traces of (E)-10-tetradecen-1-ol acetate and 1-tetradecanol acetate were also present in the extract. Traps baited with a combination of synthetic (E,E)- and (E,Z)-10,12-tetradecadien-1-ol acetates caught more males than did traps baited with females.

Insect sex pheromones: Evaporation rates of alcohols and acetates from natural rubber septa.

The half-lives (t 1/2) of alcohol sex pheromones, 1-alkanols, acetate sex pheromones, and an epoxide (disparlure) were determined on natural rubber septa. Thet 1/2 values for the homologous alcohols from decanol to heptadecanol increased regularly from 2.2 to 1117 days, but thet 1/2 of octadecanol was 609 days. Thet 1/2 values of (Z)7-, (E)7-, and (Z)9-tetradecen-1-ol acetates were 154, 168, and 199 days, respectively, whereas those of five other tested 14-carbon acetates ranged from 310 to 350 days. The dependence oft 1/2 values on chain length and double-bond position is consistent with the hypothesis that molecular size is an important variable affectingt 1/2 values. Also, in accordance with the hypothesis, when aZ-alkenyl compound has a much shortert 1/2 than the corresponding saturated compound, thet 1/2 values of theZ compound and itsE isomer may be quite different. Thus, (E)-9-tetradecen-l-ol acetate had at 1/2 of 331 days. Thet 1/2 of disparlure was 180 days. The effect of thecis-7,8 epoxide group is apparently similar to that of the olefin group in lowering thet 1/2 below the value that would be expected solely on the basis of chain length.

Microdetermination of bioethanomethrin.

A microanalytical method was developed for the determination of the experimental synthetic pyrethroid insecticide Bioethanomethrin ((5-benzyl-3-furyl) methyl trans-(+)-3-(cyclopentylidenemethyl) -2,2-dimethylcyclopropanecarboxylate). After saponification, trichloroacetyl chloride is used to form an ester from the acid moiety. Infrared and mass spectral data support the expected structures of the derivatives formed. Nanogram sensitivity is realized by utilizing a gas chromatograph with an electron capture detector.