Reduced Trap Catches Research Articles

Performance of abamectin bait formulations against German cockroaches (Dictyoptera: Blattellidae).

Commercial and experimental formulations of abamectin-based baits were evaluated in laboratory and field studies against the German cockroach, Blattella germanica (L.). In continuous exposure tests with adult males, toxicity and presumably bait consumption varied with the design of the bioassay. LT50s ranged from approximately 0.9 to > 41 d for an aerosol gel formulation for males deprived of water for 72 h before the test and for undeprived males tested with alternative food and water, respectively. Dry formulations had lower LT50s than water containing formulations for nondeprived males. There was no difference in bait toxicity between males deprived of food or water, but in arena tests, moist formulations were preferred by mixed-stage populations of cockroaches. Powder formulations were more repellent (approximately 14.9%) than moist formulations (approximately 6.4%) in Ebeling choice boxes assays, but all abamectin formulations had positive performance indices. A powder formulation reduced cockroach trap catch in infested apartments more rapidly when applied to 50, rather than 12 sites, even when the same amount of bait was applied per apartment. When applied at approximately 50 sites as a series of thin smears, an aerosol formulation provided nearly an 80% reduction in trap catch. Other abamectin formulations provided substantial, but smaller reductions in trap catch. Abamectin-based baits can reduce German cockroach populations when properly applied.

Communication disruption of male Agrotis segetum moths with one or several sex pheromone components

AbstractAttraction of male Agrotis segetum Dennis & Schiffermüller (Lepidoptera: Noctuidae) to sex pheromone traps in fields, which were treated with one or three pheromone components was investigated. Small plots of 1/4 ha size were treated with synthetic pheromone, released by 25 evenly dispersed latex rubber tube dispensers. The dispensers were loaded with either 500 μg Z5‐10:OAc (50 mg/ha), or 1000 μg Z7‐12:OAc (100 mg/ha), or a 3‐component mixture consisting of 500 μg Z5‐10:OAc + 1000 μg Z7‐12:OAc + 1000 μg Z9‐14:OAc. Pheromone traps were placed both within and outside of the treated area in a cross design, with an intertrap spacing of 15 m. Release rates from disruption dispensers were measured in the laboratory after being exposed in the field. The release rates of the components were estimated to be 0.44, 0.11, and 0.06 μg/h/dispenser for Z5‐10:OAc, Z7‐12:OAc and Z9‐14:OAc, respectively. The highest effect of disruption was achieved by the three‐component blend, resulting in a significant suppression of trap catches extending 5 m outside of the treated area. The Z5‐10:OAc treatment resulted in reduced trap catches inside the treated area, but the effect did not extend outside. Z7‐12:OAc alone did not result in any significant reduction in trap catch. The results indicate that different mechanisms may explain the disruptive effect of the treatments and that the single pheromone components are not as effective as the three‐component blend.

Small plot mating disruption trials for tufted apple bud moth, Platynota idaeusalis, in Pennsylvania apple orchards

AbstractMating disruption treatments for the tufted apple bud moth (TABM), Platynota idaeusalis (Walker), were tested in small plot trials in apple orchards in Pennsylvania. Treatments were evaluated by fruit injury and by capture of male TABM in traps baited with synthetic pheromone sources or virgin females. The TABM pheromone is a two component isomeric blend of E‐11‐tetradecen‐1‐ol (E11–14:OH) and E‐11‐tetradecenyl acetate (E11–14:Ac). A 50:50 ratio of these two components was used in standard monitoring septa and in mating disruption treatments released from either hollow fibers (‘fiber’) or PVC tubes (‘PVC’). Other pheromone blends tested included a 90:10 ratio of E11–14:Ac and E11–14:OH (‘EAc’) and its reverse (‘EOH’), mixture ‘EAc’ with 30% of the Z‐isomers (‘low EAc’), and a blend similar to the preceding with 2% Z9–12:Ac (‘generic’). These other blends were released from multi tube tape (‘tape’) or Shin‐Etsu type rope (‘rope’) dispensers. Seasonal dispenser release rate in mg ha−1 h−1 was ca. 30 for the ‘rope’ dispensers, 14 for ‘PVC’ and 6 for ‘fiber’. ‘EAc‐tape’ and ‘EOH‐tape’ were equally effective in reducing catches of males in traps baited with synthetic lures and in traps baited with virgin females. Both treatments also reduced fruit injury. ‘EAc‐rope’, ‘fiber’ and ‘PVC’ also were generally effective; whereas, the ‘low EAc’ and ‘generic’ treatments reduced trap capture less than 90% and did not reduce fruit injury. Dispenser density was positively correlated with reduction in trap capture for the ‘low EAc‐rope’ and ‘genericrope’ treatments. Traps loaded with ‘fiber’ dispensers captured more male TABM than the other treatments in non‐pheromone permeated environments. Trap capture of other tortricids was reduced in pheromone treatments. ‘EAc‐rope’ and the ‘TABM’ treatments provided mean (s.e.) percent reduction in trap catch of 99.5 (0.4) and 42.9 (10.1), respectively, for the redbanded leafroller, Argyrotaenia velutinana (Walker), and 90.4 (6.8) and 90.4 (1.3), respectively, for the obliquebanded leafroller, Choristoneura rosaceana (Harris).

Development of mating disruption for control of pine sawfly populations

AbstractMating disruption of the pine sawfly Neodiprion sertifer (Geoffroy) (Hymenoptera: Diprionidae) was strongly indicated by reduced male trap catches in pine plantations permeated with the sex pheromone, (2S, 3S, 7S)‐diprionyl acetate. The trap catch reduction was 95 to near 100% when dispensers every 10 m were used, giving a total release of about 3 mg per hectare and day. Two mg of pheromone per cotton roll dispenser maintained low catches for the whole season (about 2 months) without any renewal of disruption dispensers. An erythro‐mixture was as effective as the pure pheromone isomer. The effects of the experiments on population density and sex ratio were not possible to investigate, due to a general collapse of the population, also outside experimental plots, the year after the experiments.

Response ofDendroctonus brevicomis Le Conte (Coleoptera: Scolytidae) to different release rates and ratios of aggregation semiochemicals and the inhibitors verbenone and ipsdienol

The response of western pine beetle,Dendroctonus brevicomis Le Conte, to different release rates of the aggregation semiochemicals (attractants)exo-brevicomin, frontalin, and myrcene and the inhibitors verbenone and ipsdienol was investigated. Release rates of verbenone ranging from 0.18 mg/ 24 hr to 1.2 mg/24 hr did not result in significant reductions in mean trap catch ofD. brevicomis. In contrast, very low release rates of ipsdienol (0.02-0.4 mg/24 hr) significantly reduced trap catch compared to controls. The combination of verbenone and ipsdienol, released at rates above 0.09 and 0.02 mg/24 hr, respectively, resulted in significantly lower trap catches ofD. brevicomis in attractant-baited traps. Results of an experiment testing a factorial combination of different release rates of verbenone and attractants suggest that response is not ratio-specific. The response curve ofD. brevicomis to the levels of verbenone was similar across all levels of attractants, while the response to equivalent ratios of attractants to verbenone was not similar, suggesting that the behavior of the beetles is primarily influenced by the absolute release rate of verbenone.

(E)-11,13-tetradecadienal: Major sex pheromone component of the eastern blackheaded budworm,Acleris variana (Fern.) (Lepidoptera: Tortricidae)

(E)-11,13-Tetradecadienal (E11,13-14:Ald) is the major sex pheromone component of the eastern blackheaded budworm (EBB),Acleris variana (Fern.). The compound was identified in female pheromone gland extracts by coupled gas chromatographic-electroantennographic detection (GC-EAD), coupled GC-mass spectrometry in selected ion monitoring mode, and retention index calculations of candidate pheromone components.E11,13-14:Ald alone as trap bait was very attractive to male EBB. Addition of the corresponding diene alcohol or acetate or both did not enhance attraction. (Z)-11,13-Tetradecadienal in binary combination with (E)-11,13-14:Ald neither enhanced nor reduced trap catches. Increasing the amounts of pheromone from 0.01 to 10 µg increased trap catches, but increase of pheromone quantity above 100 µg proportionately reduced attraction. Stabilization of slowly polymerizingE11,13-14:Ald and development of a sustained, adequate release rate is required for pheromone-based monitoring of EBB populations.

The aggregation pheromone ofIps duplicatus and its role in competitive interactions withI. typographus (Coleoptera: Scolytidae)

Ips duplicatus withI. typographus co-inhabiting Norway spruce (Picea abies (L.) Karst.) would benefit from a pheromone blend distinct from that of the larger competitorI. typographus. GC-MS analysis showed thatI. duplicatus males feeding in the host produced ipsdienol (Id),cis-verbenol (cV),trans-verbenol (tV), myrtenol (Mt), andE-myrcenol (EM) and traces of 2-methyl-3-buten-2-ol (MB).I. duplicatus produced Id in approximately racemic form (48.9-54.5% (+)-(S)-isomer). The amounts of Id and EM released over a 9 day period had a maximum of 250 and 5 ng/h/male, respectively, on day 2. Exposure ofI. duplicatus males to myrcene and α-pinene resulted in the production of small amounts of Id, cV, tV, Mt, andtrans-pinocarveol, but not of EM. In laboratory bioassays with walking beetles, the pheromone component Id alone was weakly attractive while EM was inactive, but in binary combination with Id strongly synergized attraction. A combination of EM and Id at a release rate equivalent to 100–200 males was more attractive in the field than 70 unmated males in a spruce log. The addition of myrcene ( a suggested pheromone precursor of Id) to Id did not enhance trap caches, while addition of EM increased catches > 10-fold. Subtracting EM from a blend of Id, EM, cV and MB drastically reduced trap catches while subtraction of cV or MB or both had no significant effect. Addition of EM over a wide concentration range to the synthetic pheromone ofI. typographus did not reduce the attraction of females of this species in the laboratory. A two-species pheromone interaction field test releasingI. typographus pheromone components (MB + cV) at 10–1000 male equivalents (ME) andI. duplicatus pheromone (Id + EM) at 0, 10–1000 ME in all possible combinations showed both positive intraspecific dose-response effects and an interspecific inhibition. Higher release rates of EM appeared to inhibitI. typographus, especially males. In a tree colonization model, the response of the two competing species to their respective pheromones show a good separation during the mass-attack with a small initial cross-attraction. It remains to be shown whether either of the two pheromone systems have in fact evolved in the present sympatry, or if they are an incidental effect of ancestry of these phylogenetically distantIps.

Female sex pheromone of oriental tobacco budworm,Helicoverpa assulta (Guenee) (Lepidoptera: Noctuidae): Identification and field testing

Analysis of ovipositor washings from virgin femaleHelicoverpa assulta (Guenée) (Lepidoptere: Noctuidae) from Korea by gas chromatography (GC) linked to electroantennography and GC linked to mass spectrometry resulted in the identification of nine compounds, hexadecanal, (Z)-9-hexadecenal, (Z)-11-hexadecenal, hexadecyl acetate, (Z)-9-hexadecenyl acetate, (Z)-11-hexadecenyl acetate, hexadecan-l-ol, (Z)-9-hexadecen-l-ol, and (Z)-11-hexadecen-1-ol. However, ovipositor washings from females from Thailand contained mainly the 16-carbon aldehydes with very small amounts of (Z)-9-hexadecenyl acetate. Field tests conducted in Korea, China, and Thailand indicated that a binary blend of (Z)-9-hexadecenal and (Z)-11-hexadecenal was sufficient for attraction, although the most attractive ratio of compounds varied with location. In Korea a 20∶1 blend of compounds was the most attractive, while in Thailand a 7.5∶1 blend was most attractive. In China both blends of hexadecenal isomers were equally attractive. Addition of the hexadecenyl acetates to the 20∶1 blend of hexadecenals in the ratio of 1∶3.3 increased the trap catch of maleH. assulta compared to lures containing the aldehydes alone in Korea but reduced trap catch in China. Addition of the hexadecenyl acetates to the 7.5∶1 blend of hexadecenals had no significant effect on trap catch in Thailand or China compared to the aldehydes alone. The addition of the 16-carbon alcohols to the aldehydes had a significantly inhibitory effect in all three countries, suggesting they are not pheromone components. Taken together these results indicate thatH. assulta is polymorphic with at least two populations responding to different sex pheromones.

Response ofDendroctonus brevicomis andIps paraconfusus (Coleoptera: Scolytidae) to combinations of synthetic pheromone attractants and inhibitors verbenone and ipsdienol

DendroctonusBrevicomis andIps paraconfusus are sympatric bark beetle species colonizingPinus ponderosa in western North America. Interspecific and intraspecific competition for resources is, in part, mediated through semiochemicals. The response ofD. brevicomis to its attractant pheromone was significantly reduced by simultaneous release of either verbenone or racemic ipsdienol. Trap catch was significantly further reduced by including both inhibitors with the attractant pheromones. However, although the response ofIps paraconfusus was significantly inhibited with the addition of either verbenone or racemic ipsdienol, both compounds together did not result in a significant further reduction in trap catch. There was a trend for greater reduction in response ofD. brevicomis to attractant pheromones with increased release rates of either 69% (+)-/31% (-)-verbenone or 84% (-)-/16% (+)-verbenone. Response of associates to attractants and inhibitor combinations was also determined.

Interactive Effects of l-Octen-3-ol and Carbon Dioxide on Mosquito (Diptera: Culicidae) Surveillance and Control

Responses of natural populations of biting Diptera were studied at Everglades National Park, Fla., to three levels (0, 3.0, and 41.1 mg/h) of 1-octen-3-ol (octenol), four levels (0, 20, 200, and 2,000 ml/min) of carbon dioxide (CO2), and their combinations. Catches of mosquitoes (Aedes taeniorhynchus (Wiedemann), Culex [Melanoconion]) spp., Cx. nigripalpus Theobald, and Wyeomyia spp.) and one tabanid (Diachlorus ferrugatus (F.)) were affected significantly by CO2 and octenol. Significantly greater numbers of all taxa were collected as the level of CO2 was increased. The 3.0-mg/h release rate of octenol alone resulted in increased trap catches relative to no bait for all taxa except Cx. (Melanoconion) spp., whereas the 41.1-mg/h release rate alone generally reduced trap catches relative to either no bait or 3.0 mg/h octenol. The effect of CO2 and octenol was additive for Cx. (Melanoconion) spp. and D. ferrugatus and synergistic for Ae. taeniorhynchus. Six octenol-supplemented CO2 treatments produced mixed results for Cx. nigripalpus.

Female sex pheromones of Chilo spp. (Lepidoptera: Pyralidae) and their development in pest control applications

Female sex pheromone components have been identified for seven species of Chilo, pests of cereals and sugar-cane. Synthetic pheromone blends for C. suppressalis, C. sacchariphagus, C. sacchariphagus indicus, C. auricilius and C. zacconius have shown satisfactory attractiveness to male moths in the field. Blends for C. partellus and C. infuscatellus seem to be incomplete. Pheromones and related compounds have been investigated for control of C. suppressalis by mating disruption in the Philippines, Japan, Spain and Korea. These studies have shown not only trap catch reduction, but also reduced viable egg production in field cages and effective control of damage by this pest on areas up to 60 ha. Initial studies have been carried out on control of C. sacchariphagus by mating disruption in Mauritius, and both the pheromone and an inhibitor have been shown to cause trap catch reduction of C. auricilius in India. Attempts have been made to control C. sacchariphagus indicus by mass trapping in India.

THE USE OF MONOTERPENES AS KAIROMONES BY IPS LATIDENS (LECONTE) (COLEOPTERA: SCOLYTIDAE)

AbstractThe responses of Ips latidens (LeConte) to multiple-funnel traps baited with various monoterpenes were determined in stands of lodgepole pine in British Columbia. β-Phellandrene was attractive to I. latidens in the absence of the pheromone ipsenol. β-Phellandrene increased the attraction of I. latidens to ipsenol-baited traps while α-pinene, 3-carene, terpinolene, and myrcene reduced trap catches. Differential responses by males and females to sources of ipsenol with or without β-phellandrene suggest that the information conveyed to males differs from that conveyed to females. Species-specific responses to monoterpenes by I. latidens and three sympatric species of scolytids suggest that unique combinations of kairomones could be important in facilitating matings with conspecifics. Pheromones need not be the sole constituent of species-specific chemical messages.

Effect of Dosage and Ratio of Sex Pheromone Components on Behavior of Chrysoteuchia topiaria (Zeller) (Lepidoptera: Pyralidae)

When the dosage of the primary pheromone component (Z)-ll-hexedecenal (Zll-16:AI) of the cranberry girdler, Chrysoteuchia topiaria (Zeller), was varied from 0.03 to 10 mg in field tests, maximum catch was obtained at a dosage of less than 1 mg. When (Z)-9-hexadecenal (Z9-16:AI)was present at 0.3, 1, or 3% of Zll-16:AI, trap catch was proportional to the logarithm of the dosage over the same concentration range. The amount of Z9-16:Althat produced maximum trap catches within calculated confidence limits of each dosage ranged from 0.2 to 2.1% when the dosages of Zll-16:Al were 0.3, 1,3, and 10 mg. Z9-16:AI at 1% always was included within the confidence limits of these dosages. The two higher dosages captured significantly more males than the two lower dosages, but trap catches were not significantly different between dosages of 0.3–1 and 3–10 mg. The reduced trap catch by Zll-16:AI alone for dosages above 1 mg was the result of the absence of an important pheromone component. In flight tunnel studies, Zll-16:AI induced limited plume-oriented flight (19% of tested males) at a dosage of 0.03 mg only, and males did not reach the source. The percentage of males exhibiting upwind flight in the plume increased dramatically when Z9-16:AI was present. At a dosage of 0.3 mg, upwind flight in the plume was 0% for the single component and 90% for the two components. Maximum upwind flight occurred at dosages from 0.03 to 3 mg and, as occurred in field tests, the Z9-16:AI at 1% of Zll-16:AI always was included within the calculated confidence limits for these dosages. The 3-mg dosage of Zll-16:AI reduced the number of males landing on the septa.

Attraction of Western Grapeleaf Skeletonizer Males (Lepidoptera: Zygaenidae) to S-(+)-2-Butyl-(Z)-7-Tetradecenoate

Peak catches of male Harrisina brillians Barnes & McDunnough in traps baited with the sex pheromone S-(+)-2-butyl-(Z)-7-tetradecenoate were first obtained at a dosage of 100 µg per septum (estimated release rate of 8.6 ng/h). At higher dosages, trap catches were not significantly greater. Addition of the R-(−) enantiomer to 500 µg s-(+)-2-butyl-(Z)-7-tetradecenoate per septum had no effect at 3 or 9% but significantly reduced trap catches at 23 and 50%. In a comparison of the 500-µg dosage of the S-(+) enantiomer and unmated female H. brillians moths in traps, female-baited traps attracted 2.5 times as many males as did pheromone-baited traps. It is suggested that additional pheromone components are produced by calling female H. brillians .

Evidence for (E,Z)-8,10-dodecadienyl acetate as the major component of the sex pheromone of the eastern pine seedworm,Cydia toreuta (Lepidoptera: Tortricidae)

The sex pheromone ofCydia toreuta (Grote), the eastern pine seedworm, was investigated using electroantennogram (AG) measurements, gas chromatography (combined GC-FID-EAD) measurements, and field tests. (E,Z)-8,10-dodecadienyl acetate (E,Z8,10-12:Ac) and (E,E)-8,10-dodecadienyl actetate (E,E8,10-12: Ac) produced both the highest EAG and EAD responses. Only a single antennal stimulatory peak was observed when female abdominal tip extracts were analyzed by GC-FID-EAD, which corresponded exactly with that of authenticE,Z8,10-12: Ac. Field tests confirmedE,Z8,10-12: Ac as the major pheromone component. TheE,Z isomer by itself caught equivalent numbers of male moths as did caged females. The addition of theE,E isomer to theE,Z form increased trap catch, although not significantly (P = 0.05). The addition of (Z,Z)-8,10-dodecadienyl acetate to theE,Z isomer significantly (P=0.05) reduced trap catch, while the addition of (Z,E)-8,10-dodecadienyl acetate to theE,Z form also decreased trap catch, but not significantly (P=0.05).

SEX PHEROMONE OF RETINIA METALLICA (BUSCK) (LEPIDOPTERA: TORTRICIDAE): IDENTIFICATION AND FIELD STUDIES

AbstractThe major sex pheromone component from female moths of Retinia metallica (Busck) was identified as Z7,E9-dodecadienyl acetate (Z7,E9-12:Ac) by a combination of electroantennographic (EAG), gas chromatographic (GC), and mass spectrometric analyses. In field tests, males of R. metallica were strongly attracted to Z7,E9-12:Ac. Addition of Z7,Z9-12:Ac, E7,Z9-12:Ac, Z7,E9-dodecadienol (Z7,E9-12:OH), andZ7-dodecenyl acetate (Z7-12:Ac) to Z7,E9-12:Ac did not significantly alter trap catch. However, the addition of E9-dodecenyl acetate (E9-12:Ac) and Z9-12:Ac reduced trap catch. Trap catch was affected by height of placement; traps placed in the upper third of the tree (6 m) caught significantly more males than traps placed at lower heights.

Gypsy moth mating disruption: Dosage effects

Small (1-hectare) plots in a dense gypsy moth (Lymantria dispar) infestation were treated with 5, 50, or 500 g racemic disparlure, and effects on male trap catch and mating behavior were studied. Capture of males in traps baited with 1, 10, 100, or 1000 μg (+)-disparlure declined as disruptant dosages increased. Traps with high levels of attractant caught moths when capture in those with lower baitings was dramatically reduced. While all disruptant dosages reduced trap catch, it was reducd at least 95% at all attractant levels at the 500-g disruptant application rate. Visual estimates indicated that male moth density was similar in treated and control plots; female mating success was reduced 6.5, 34.5, and 84% in plots with 5, 50, and 500 g/ hectare disruptant, respectively. The duration of precopulatory and copulatory periods was similar for all females that were observed mating, regardless of disruptant treatment. It is proposed that reduced trap catch and female mating success are due to effects of atmospheric synthetic disparlure (disruptant) camouflaging natural attractant point sources.

Attraction of Harrisina americana and Acoloithus falsarius Males (Lepidoptera: Zygaenidae) to (R)-(−)-2-butyl-(Z)-7-tetradecenoate1

Males of two species of Zygaenidae, the grapeleaf skeletonizer, Harrisina americana (Guerin), and Acoloithus falsarius Clemens, were attracted to ( R )-(−)-2-butyl-( Z )-7-tetradecenoate in field trapping tests. Presence of the ( S )-(+) enantiomer in racemic 2-butyl-( Z )-7-tetradecenoate appeared to reduce trap catches of males of both species. Pure ( R )-(−)-2-butyl-( Z )-7-tetradecenoate may be useful as an attractant for monitoring emergence of grapeleaf skeletonizer moths and their population cycles in grape vineyards.

A Sex Attractant Synergist for Trichoplusia oxygramma (Lepidoptera: Noctuidae)

Trichoplusia oxygramma (Geyer) is closely related to the cabbage looper, Trichoplusia ni (Hubner), although it is not a pest species. Like many other Plusiinae, males are attracted in the field to traps baited with (Z)-7-dodecen-1-ol acetate (Z7-12:Ac), the major component of the sex pheromone of the female cabbage looper (Mitchell et al. 1972). During an experiment in which traps were baited with combinations of female cabbage looper sex pheromone components, T. oxygramma males were caught in traps baited with a combination of Z7-12:Ac and (Z)-9-tetradecen-1-ol acetate (Z9-14:Ac). We report here the result of a subsequent experiment demonstrating an increased sex attractant response by T. oxygramma males to Z7-12:Ac plus Z9-14:Ac compared to Z7-as:Ac alone, as indicated by trap catches. Plastic bucket traps (Universal moth trap, International Pheromones, Merseyside, England) were baited with two lures; a 1-mg dosage of Z7-12:Ac or a combination of 1-mg Z7-12:Ac and 90 ,ug Z9-14:Ac on a rubber septum. This ratio of 10 to 0.9 for Z7-12:Ac to Z9-14:Ac approximates the ratio of those components reported by Bjostad et al. (1984) for the female cabbage looper pheromone and is similar to the ratio in our original experiment in which T. oxygramma males were trapped. Septa were pre-extracted, handled and loaded as described by Landolt and Heath (1986). Traps were hung from shrubs about 1 m above ground level in uncultivated fields near Gainesville, Florida during Sept. and Oct. 1985. Traps were positioned as four treatment pairs with about 24m between paired traps. These were checked and septa switched daily between paired traps. Septa were replaced after 1 week. Treatment means were separated by Student's t-test at p > 0.05. Mean numbers of male T. oxygramma caught per week in traps baited with Z7-12:Ac plus Z9-14:Ac were significantly higher than in traps baited with Z7-12:Ac alone (Table 1), indicating a synergistic effect by Z9-14:Ac on the attractant response of male T. oxygramma to Z7-12:Ac. Although (Z)-9-14:Ac is a minor component of the sex pheromone of female T. ni (Bjostad et al. 1984), it did not have any synergistic effects on the response of T. ni males to Z7-as:Ac in a wind tunnel bioassay (Linn et al. 1984). Landolt and Heath (1986) also reported that numbers of male P. includens caught in traps were reduced greatly by the addition of Z9-14:Ac to Z7-12:Ac, indicating an inhibitory effect which may function in preventing interspecific courtship and mating between Trichoplusia spp. and P. includens. (Z)-9-Tetradecen-1-ol acetate also inhibits the attractant response (reduced trap catches) of two other species of Plusiinae, Autographa californica (Speyer) and A. flagellum (Walker), to Z7-12:Ac (Steck et al. 1979). Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.

Sex pheromones and reproductive isolation in four european small ermine moths

Reproductive isolation among four sympatric small ermine moths (Yponomeuta) is analyzed in terms of niches in the sexual communication channel. Potential pheromone components were identified from pheromone gland secretions ofY. evonymellus,Y. cagnagellus,Y. padelius, andY. vigintipunctatus by gas chromatography with flame ionization and electroantennographic detection and tested for behavioral activity in the field. The species were found to share (Z)-11-tetradecenyl acetate (Z11-14: OAc) in combination with varying proportions of theE isomer as primary sex pheromone components.Y. cagnagellus differs from the rest of the species by having only a small amount (1.5%) ofE isomer relative toZ isomer in its pheromone. The closely relatedY. padelius has a three-component pheromone including large amounts (ca. 400%) of (Z)-11-hexadecenyl acetate (Z11-16:OAc) in addition toZ11-14: OAc (100%) andE11-14: OAc (34%).Z11-16: OAc appears to reduce trap catches ofY. evonymellus andY. vigintipunctatus when added to the pheromone. Although these species are the two most distantly related European small ermine moths, they seem to share the same sex pheromone, i.e.,Z11-14∶OAc (+20%E) and (Z)-11-tetradecenol. Our interpretation is that this might have been the sex pheromone of the ancestor of today'sYponomeuta species.