Influence ofHeliothis virescens sex pheromone dispensers on captures ofH. zea males in pheromone traps relative to distance and wind direction

Evaluations conducted by placingHeliothis virescens (F.) sex pheromone (virelure) dispensers at different distances in the predominant downwind and upwind directions fromHeliothis zea (Boddie) pheromone traps indicated that reductions inH. zea male captures were greatest relative to distance when theH. zea traps were located downwind from the virelure dispensers than when the traps were located upwind. When operating traps for both species at the same site, the influence of virelure dispensers on captures inH. zea pheromone traps would be minimized by placing theH. zea traps upwind of theH. virescens traps and, if wind direction is variable, the traps should be spaced at least 75 m apart.Lepidoptera: Noctuidae.In cooperation with the Texas Agricultural Experiment Station, Texas A&M University, College Station, Texas 77843. This paper reports the results of research only. Mention of a commercial or proprietary product in this paper does not constitute an endorsement of this product by USDA.     

Identification of sex pheromone components from pheromone gland volatiles of the tomato looper,Plusia chalcites (Esp.)

The sex pheromone glands ofPlusia chalcites release, dodecyl acetate, (Z)-7-dodecenyl acetate, (Z)-9-dodecenyl acetate, 11-dodecenyl acetate, (Z)-8-tridecenyl acetate, and (Z)-9-tetradecenyl acetate. A combination of capillary GC, GC-MS, and dimethyl disulfide derivatization enabled a rigorous identification of all these compounds, some of which were previously found in gland extracts. Bioassays in a flight tunnel showed that a ternary blend of (Z)-7-dodecenyl acetate, (Z)-9-dodecenyl acetate, and (Z)-9-tetradecenyl acetate elicited directed flights from 85 to 100% of the males tested and elicited copulation attempts, at the end of the flights, from 44 to 74% of the males tested. This blend was equal in activity to the natural gland extract. Addition of the other acetates had only a slight influence on the activity of this mixture. Substitution of either (Z)-9-dodecenyl acetate or (Z)-9-tetradecenyl acetate in this blend by 11-dodecenyl acetate gave two ternary mixtures which also elicited high levels of courtship activity, almost as high as that of the original blend. Addition of (Z)-7-dodecenyl alcohol inhibited almost totally the flight activity of males.Lepidoptera: Noctuidae.Contribution from the Agricultural Research Organization (ARO) No. 1701-E, 1986 series.     

Terminal steps in pheromone biosynthesis byHeliothis virescens andH. zea

In vivo application to the sex pheromone gland ofHeliothis Virescens andH. Zea of large quantities of alcohols normally present in small amounts resulted in the preferential conversion of the alcohols to the corresponding pheromonal aldehydes. Amounts of the minor component aldehydes were increased up to 15-fold by selectively applying large quantities of the alcohol precursors. Using this technique, we have inducedH. virescens to convert bombykol, the sex pheromone of the silkworm, to the corresponding aldehyde, bombykal, and have induced femaleH. zea to produce the same sex pheromone components used byH. virescens by applying tetradecanol and (Z)-9-tetradecenol to the surface of the gland. Further, treatedH. zea females were attractive toH. virescens males and caused males to attempt interspecific copulation repeatedly. We have also found that the enyzme involved in this conversion is dependent on the presence of molecular oxygen, indicating that a nonspecific alcohol oxidase is responsible for the terminal biosynthetic step in pheromone production by bothH. virescens andH. zea.Mention of a commercial product or proprietary does not constitute endorsement by either the University of Guelph or U.S.D.A.     

Behavioral responses of maleHeliothis zea moths in sustained-flight tunnel to combinations of 4 compounds identified from female sex pheromone gland

Each of the four compounds that have been identified from sex pheromone glands ofHeliothis zea female moths was examined for its ability to elicit sexual responses from male moths in a flight tunnel. Males flew upwind to (Z)-11-hexadecenal alone, but greater levels of behavioral activity were evoked with the addition of (Z)-9-hexadecenal to the treatment. Addition of hexadecanal or (Z)-7-hexadecenal to the initial two components had no effect in raising the behavioral response of the males in the flight tunnel whether added singularly at both the normal gland-emission ratio or at varying ratios or in combination at the normal ratio. Live, calling females elicited levels of sexual activity from males not significantly different from that elicited by the mixture of (Z)-11- and (Z)-9-hexadecenal on cotton wicks.Lepidoptera: Noctuidae.     

Preferences of matedHeliothis virescens andH. subflexa females for host and nonhost volatiles in a flight tunnel

In flight-tunnel bioassays, mated femaleHeliothis subflexa (Gn.) moths demonstrated in dual-choice tests a significant preference for volatiles from an extract of their only known host,Physalis spp. (groundcherry). However,H. virescens (F.), a polyphagous species, responded positively by anemotaxis to extracts from susceptible tobacco, cotton,Desmodium tortuosum (host plants), and groundcherry, a nonhost.H. virescens females did not fly to volatiles emanating from an extract of a resistant tobacco cultivar.This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or the recommendation of its use by USDA.     

Effect of oviposition deterrents from elderberry on behavioral responses byHeliothis virescens to host-plant volatiles in flight tunnel

In flight-tunnel assays, mated femaleHeliothis virescens (F.) moths responded by positive anemotaxis to volatiles from extracts of two host plants (cotton and tobacco), but they did not fly to an extract from elderberry (Sambucus simpsonii Rehd.), a nonhost that contains an oviposition deterrent forH. virescens. When the elderberry extract was mixed with extract from either cotton or tobacco, the flight response by moths to volatiles emanating from the extract blends was reduced significantly at most doses when compared to the positive response to extracts from either host alone. The number of landings (including brief contacts) and landings that resulted in oviposition on the substrates treated with extract blends also were reduced significantly in most tests.This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or the recommendation of its use by USDA.     

Rate of release of spruce budworm pheromone from virgin females and synthetic lures

The rate of pheromone [(E)- and (Z)-11-tetradecenal] release from calling virginChoristoneura fumiferana females and synthetic lures was determined in both static and aerated atmospheres. In a static system ca. 2 ng/hr was recovered per female. Owing to the > 75% adsorption onto the females' bodies in static atmospheres, the actual release rate has to be corrected to roughly 9–27 ng/hr, depending on the percentage adsorbed. In the air-flow system, females were found to release between 4 and 20 ng/hr. On a 168 light-dark cycle, calling began 1–2 hr before lights-off and continued nonstop until lights-on. Pheromone was emitted throughout calling, while no pheromone was detected during the noncalling periods.Lepidoptera: Tortricidae.Published as Journal Article No. 10258 of the Michigan Agricultural Experiment Station.     

Female sex pheromone of iris borer,Macronoctua onusta (Lepidoptera: Noctuidae)

Chromatographic and mass spectrometry studies of heptane extracts of the ovipositors of the iris borer,Macronoctua onusta, showed that the females produce several compounds that are the same as those produced by females of the tobacco budworm,Heliothis virescens. In trapping experiments, a mixture of (Z)-11-hexadecenal, (Z)-11-hexadecen-1-ol, and (Z)-9-tetradecenal (9442) proved to be the minimum set of compounds required to cause effective capture of iris borer males in the field.     

Attraction ofHeliothis virescens (F.) (Lepidoptera: Noctuidae) to volatiles from extracts of cotton flowers

Mated and virgin female and virgin male tobacco budworm moths,Heliothis virescens (F.), responded via directed upwind flight in wind-tunnel bioassays to volatiles from floral extracts of cotton,Gossypium hirsutum L. Significantly more male and female moths landed on cloth dispensers treated with a methylene chloride extract of debracted flowers than on control dispensers treated only with methylene chloride. Only mated females landed in significant numbers on the dispensers treated with extract of cotton squares, flowers (including bracts), or flower petals. After landing, most of the moths examined the dispensers by probing with their antennae, proboscis, and/or ovipositor.     

Novel sex pheromone components from the fall cankerworm moth,Alsophila pometaria

A sex pheromone extract from fall cankerworm moths,Alsophila pometaria, attracted conspecific males in field tests. Four EAG-active components were isolated from the extract and identified by GC-MS, highfield PMR spectroscopy, and microchemical techniques asn-nonadecane (I), (Z,Z,Z)-3,6,9-nonadecatriene (II), (Z,Z,Z,E)-3,6,9,11-nonadecatetraene (III), and (Z,Z,Z,Z)-3,6,9,11-nonadecatetrane (IV). Studies of the behavioral responses of male moths in a flight tunnel to the isolated components showed II, III, and IV were the major components of the sex pheromone. No sex pheromone behavioral responses were observed for I.Lepidoptera: Geometridae.issued as NRCC No. 22964.     

Influence of (Z)-11-hexadecen-1-ol on field performance ofHeliothis virescens pheromone in a PVC dispenser as evidenced by trap capture

Field studies were conducted to determine the effect of (Z)-11-hexadecen-1-ol (Z11-16 OH) on capture of tobacco budworm (TBW),Heliothis virescens (F.), males when added to two-component (HV-2) and six-component (HV-6) pheromone blends dispensed from a polyvinyl chloride (PVC) substrate. Numbers of males caught in traps baited with PVC dispensers containing 0.25% Z11-16 OH, relative to total pheromone content, were significantly higher than numbers caught with dispensers containing noZ11-16 OH. Catches of TBW were also increased significantly in some tests whenZ11-16 OH was formulated in the bait at a 1% concentration. Catches were significantly reduced with dispensers containing 5.95%Z11-16 OH compared with those containing noZ11-16 OH. There were no differences in catch between traps baited with HV-2 vs. HV-6 or HV-2 + 0.25%Z11-16 OH vs. HV-6 + 0.25%Z11-16 OH when formulated in PVC substrate.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

Identification of sex pheromone components of darksided cutworm,Euxoa messoria,and modification of sex attractant blend for adult males

Eleven pheromone-like compounds were identified in excised abdomen tip extracts of calling adult females of darksided cutworm,Euxoa messoria (Harris). The essential pheromone components were (Z)-7- and (Z)-11-hexadecenyl acetates in a ratio of 140, which agreed with an attractant blend developed empirically by field testing the attractancies of synthetic blends. The pheromone component, (Z)-11-hexadecenol, improved the attraction of darksided cutworm males whereas the components (Z)-9-tetradecenyl acetate and (Z)-7-dodecenyl acetate inhibited their attraction. The other pheromone-like compounds identified in the female extracts had no obvious effect on the attraction of darksided cutworm males. Three compounds that functioned as parapheromones when substituted for (Z)-7-hexadecenyl acetate in the two-component blend were (Z)-7-pentadecenyl, (Z)-7-tetradecenyl, and (Z)-7-tridecenyl acetates. (Z)-11-hexadecenal was not detected in the female extracts, but it had a synergistic effect on the attraction of darksided cutworm moths and inhibited the attraction of male moths of a nontarget species,Helotropha reniformis (Grote). As a trap bait for monitoring purposes, we recommend a four-component blend of (Z)-7-hexadecenyl acetate, (Z)-11-hexadecenyl acetate, (Z)-11-hexadecenol, and (Z)-11-hexadecenal at 12.5, 500, 1, and 10 g/red rubber septum dispenser containing 5 g of antioxidant 2,6-tert-butyl-4-methyl phenol. This blend is effective under field conditions for at least six weeks.     

Comparison of sex pheromone composition and pheromone-mediated male behavior of laboratory-reared and wildHeliothis zea (Lepidoptera: Noctuidae)

Analysis of ovipositor extracts of lab-reared (> 120 generations) and wildHeliothis zea indicated small but significant differences in the percent composition of the four aldehyde components of the sex pheromone. (Z)-11-hexadecen-1-ol (Z11–16OH) was present in both populations and amounted to only 2.8% of the total pheromone. There was no significant difference in four of the six behavioral categories between lab-reared and wild males exposed to the four-component sex pheromone in the flight tunnel. Ninety and 84% males flew to the pheromone source, respectively. However, with the addition ofZ11–16OH to the pheromone blend, none of the wild males flew upwind to the stimulus source, whereas 36% of the lab-reared males completed the flight. It is suggested that prolonged inbreeding in closed quarters rendered these males less discriminating to qualitative differences in a pheromone blend.     

Effects of pheromone components and their degradation products on the response ofHeliothis spp. to traps

None of the isolated degradation products of (Z)-11-hexadecenal [(Z)-11-HDAL] affected the catches of either tobacco budworm [Heliothis virescens (F.)] or bollworm [H. zea (Boddie)] moths when dispensed with pheromone from cotton dental rolls in cone traps. Also, none of the degradation products of (Z)-9-tetradecenal [(Z)-9-TDAL] had an effect on trap catches of tobacco budworm moths. Two of the three chemicals that have previously been identified in ovipositor washes of tobacco budworms but that are absent in those of bollworms caused a reduction in capture of bollworms: (Z)-9-TDAL (1.0 g/trap) caused a 96% reduction in trap catch and (Z)-11-hexadecen-1-ol (20.0 g/trap) caused a similar reduction. Tetradencenal (40 g/trap) had no effect on trap catch.In cooperation with the Texas Agricultural Experiment Station, Texas A&M University, College Station, Texas 77843.This paper reports the results of research only. Mention of a pesticide in this paper does not constitute a recommendation for use by the USDA nor does it imply registration under FIFRA as amended. Also, mention of a commercial or proprietary product in this paper does not constitute an endorsement of this product by the USDA.     

Sex pheromone chemistry of the female tobacco budworm moth,Heliothis virescens

(Z)-11 -Hexadecenal (77–91%), (Z)-7-hexadecenal (0.1–2%), (Z)-9-hexadecenal (0.3–2%), hexadecanal (3–19%), (Z)-11-hexadecen-1-ol (1–5%), tetradecanal (1–3%), and (Z)-9-tetradecenal (1–3%) were identified from the heptane washes of the ovipositor of femaleHeliothis virescens (F.) females. In field bioassays, a 152-g mixture of these seven compounds deployed in an insect trap exceeded the attractiveness of 4 virgin femaleH. virescens for males and was 5–6 times more attractive than a mixture of (Z)-1 1-hexadecenal and (Z)-9-tetradecenal (virelure) that was previously reported as the sex pheromone of the species. Four of the seven compounds produced byH. virescens females are also produced byH. zea (Boddie). Specificity of pheromonal signals among the two species is ostensibly dependent upon one or more of the three additional compounds [tetradecanal, (Z)-9-tetradecenal, and (Z)-1 1-hexadecen-1-ol] produced by femaleH. virescens.     

Evidence for presence and nature of female sex pheromone ofBrithys crini fabricius (Lepidoptera: Noctuidae)

The existence of a female sex pheromone of the noctuid mothBrithys crini Fabricius was confirmed in both laboratory bioassay and field tests. Crude extracts and airborne volatiles from females were analyzed by gas chromatography and mass spectrometry and the data compared with authentic compounds. The primary sex pheromonal compound was Z11-16: Ald. Scanning electron microscopy showed that the external surface of the sex pheromone gland was covered with folds that might increase the sex pheromone evaporation area.     

Intrapopulational changes in sex pheromone composition during scotophase in oriental tobacco budworm,Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae)

Solvent extracts of individual pheromone glands were prepared from femaleHelicoverpa assulta (Guenée) at 2-hr intervals throughout the scotophase. The amounts of female sex pheromone components, (Z)-9-hexadecenal, (Z)-11-hexadecenal, (Z)-9-hexadecenyl acetate, and (Z)-11-hexadecenyl acetate, in the extracts were determined by gas chromatographic analysis. Although females called from early scotophase (2 hr) until late scotophase (6 hr) the quantity of extracted pheromone remained high at 8 hr, the end of the scotophase. More than 70% of the pheromone gland extracts contained sex pheromone components regardless of whether the donor females had been called or resting. Pheromone components were absent from gland extracts prepared at the onset of the scotophase. The quantity of (Z)-9-hexadecenal and (Z)-11-hexadecenal increased rapidly to reach a maximum of approximately 260 and 30 ng/female, respectively, that was maintained for up to 8 hr, the duration of the scotophase. The quantity of (Z)-9-hexadecenyl acetate and (Z)-11-hexadecenyl acetate increased continuously during the scotophase to peak at 600 and 30 ng/female, respectively, 8 hr into the scotophase. At the end of scotophase the quantity of all pheromone components decreased significantly.     

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 100421, 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 g Z9-14:Ac+16 g Z9-14:OH+42 g Z11-16:Ac is suggested for use in monitoring traps.Lepidoptera: Pyralidae: Phycitinae.     

Interspecific Pheromone Plume Interference Among Sympatric Heliothine Moths: A Wind Tunnel Test Using Live, Calling Females

Three species of North American heliothine moths were used to determine the level at which interspecific female interference of male attraction to conspecific females occurs. We used live calling females of Heliothis virescens, H. subflexa, and Helicoverpa zea, as lures for conspecific males in a wind tunnel, and then placed heterospecific females on either side of the original species such that the plumes of the three females overlapped downwind. In nearly all combinations, in the presence of heterospecific females, fewer males flew upwind and contacted or courted the source than when only conspecific females were used in the same spatial arrangement. Males did not initiate upwind flight to solely heterospecific female arrangements. Our results show that the naturally emitted pheromone plumes from heterospecific females of these three species can interfere with the ability of females to attract conspecific males when multiple females are in close proximity. However, the fact that some males still located their calling, conspecific females attests to the ability of these male moths to discriminate point source odors by processing the conflicting information from interleaved strands of attractive and antagonistic odor filaments on a split-second basis.     

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 (Z9–12Ac). Also, strong responses were obtained from (Z)-11-tetradecenal (Z11–14A1) and (Z)-11-tetradecen-1-ol (Zl1–14OH). At a dosage of 0.3 ng,Z11–14A1 produced a stronger response thanZ11–14OH, while at a dosage of 30 ng,Z11–14OH andZ11–14A1 produced equal responses. Gas chromatographic and mass spectral analysis of extracts of female sex pheromone glands showed the presence ofZ9–12Ac, tetradecan-1-ol (14OH), (E)-11-tetradecen-1-ol (E11–14OH),Z11–14OH, hexadecan-1-ol, and hexadecan-1-ol acetate in a ratio of 0.62003710014035. In field tests,Z9–12Ac andZ11–14OH together were required for trap catch, and addition ofZ11–14A1,E11–14OH, 14OH, or (Z)-11-tetradecen-1-ol acetate did not increase catch. Ratios in rubber septa of 0.599.5 to 1.598.5 (Z9–12 Ac/Z11–14OH) captured the most males and captures were statistically equivalent for dosages of 10–1000 g/rubber septum. Traps baited with the synthetic lure produced better catches than those baited with females.Lepidoptera: Yponomeutidae.