Absorption and release of pheromone ofEpiphyas postvittana (Lepidoptera: Tortricidae) by apple leaves

The absorption and release of the pheromone ofEpiphyas postvititana (Lepidoptera: Tortricidae),E 11–14: OAc andE,E 9, 11–14: OAc (95:5) by apple leaves was studied using electroantennograms (EAG) and sticky traps baited with pheromone-treated leaves. Leaves exposed to an airstream containing pheromone reached a constant level of pheromone release within 3 min. Release occurred over a period greater than 24 hr, following removal of leaves from the pheromone-saturated environment. Pheromone-treated leaves were effective as lures in sticky traps for at least three nights, although the average catch per night decrease logarithmically with time. In the field, pheromone was detected by EAG on leaves harvested from up to 25 cm away from a central point source of pheromone. The shape of a surface representing equal pheromone re-release from leaves around a central point source was defined by interpolation from a three-dimensional transect. Leaves harvested from 5 cm under the dispensers showed the highest pheromone release rate. Leaves downwind of the dispensers also had higher release of pheromone. In a treated orchard, significantly higher EAG measurements were recorded in the rows of trees that contained dispensers, compared to grass interrows or untreated trees. The implications of foliar pheromone adsorption and release on atmospheric concentrations and insect behavior require further investigation.     

Apple foliage enhances mating disruption of light-brown apple moth

Uptake and release of pheromone and behavioral inhibitor ofEpiphyas postvittanna by apple leaves was tested using field electroantennograms (EAG), trap catches to synthetic lures and virgin females, and chemical analysis. Trap catches in single apple trees (N=3) were monitored for six cycles of six days' duration, using delta traps baited with synthetic pheromone. Polyethylene dispensers (0, 1, 10 per tree) releasing pheromone and inhibitor were present for only the first three days of each cycle. Application of 10 dispensers per tree resulted in complete disruption of trapping, which continued for one day after dispensers were removed. Over the three nights following the removal of the dispensers (days 4–6), trap catch was 0, 10, and 15% of the control catch. In contrast, the presence of only one dispenser per tree led to 0–20% of control catches, but on the three nights following dispenser removal catches were 35, 40, and 80% of the control catch. Field EAGs indicated significantly higher relative pheromone concentrations in the trees with 10 dispensers present, compared to trees with single dispensers, but removal of dispensers produced no detectable treatment effect compared to the control trees one day after dispenser removal. In a second experiment, releases of marked male moths into apple orchard plots following the removal of polyethylene dispensers (1 hr earlier that day) resulted in significantly lower catches in traps baited with virgin females in blocks that had been treated, compared to controls. Recovery of pheromone by solvent washing of leaves loaded with 50 µg of the main component of the sex pheromone (1.26 µg/cm²) was low (2.5%). Leaves held in a pheromone-saturated atmosphere were loaded with 0.045±0.007 µg pheromone/cm². Analysis of apple leaves taken from a pheromone-treated tree at different distances from the pheromone dispenser showed a decay of the pheromone load per square centimeter with increasing distance from the dispenser, as previously indicated by EAG.     

Sex pheromone of lucerne leafroller,Merophyas divulsana (Walker) (Lepidoptera: Tortricidae): Evidence for two distinct populations

When specimens of the lucerne leafroller,Merophyas divulsana, were sampled from an area with a history of crop damage, they were found to have (E)-11-tetradecenyl acetate, hexadecyl acetate, and tetradecyl acetate as principal components of the pheromone gland. A synthetic mixture of these compounds proved to be a successful lure in delta traps. On the other hand, apparently identical moths collected in areas with no history of crop damage were found to have (Z)-11-tetradecenyl acetate as the major component of the sex pheromone gland. The distribution of the two moths provides the basis for a plausible explanation of the regional pest activity reported forM. divulsana.     

Effect of design of a sex-pheromone-baited delta trap on behavior and catch of maleEpiphyas postvittana (Walker)

Through field trials and wind-tunnel studies, we have demonstrated that certain structural features of a sex-pheromone-baited delta trap affect catch of light-brown apple moth,Epiphyas postvittana, males, by influencing behaviors used to enter and exit the trap. Field catch of males was dependent upon length (and width) of the trap, with increases in length yielding linear increases in catch. In the wind tunnel, similar numbers of males entered the two traps, but significantly fewer males exited the longer trap within 1 min after entering it. Although males landed on the sticky surface at similar distances from the downwind entrances of the traps, they were stuck farther upwind on the longer trap. Thus, it is probable that the increase in field catch with increase in trap length relates to the increase in distance (and hence time) that males walk on the sticky surface, towards the pheromone source, before attempting to exit. The bottom barriers (as well as additional barriers at the top and sides) at the entrances of the trap also significantly influenced trap catch. The barriers apparently influence trap catch in two ways. Firstly, they hinder the exit of males from the trap, thus diverting males back into the trap and increasing their chance of being caught. Secondly, they influence where the male lands on the sticky surface; with higher barriers, males land farther upwind (i.e., nearer the source), and thus farther from an exit. Finally, as the source was suspended higher above a horizontal surface, greater numbers of males landed on the source. This result shows that the position where a maleE. postvittana lands is influenced by the relationship of the source to the surface and suggests that trap catch of males may similarly be influenced (i.e., by inducing males to land farther from the exits).     

Sex pheromone of the false codling mothCryptophlebia leucotreta (Lepidoptera:Tortricidae)

The sex pheromone ofCryptophlebia leucotreta females is a mixture of (E)-8- and (Z)-8-dodecenyl acetate (dda). The compounds have been isolated from extracts ofC. leucotreta females and were identified by means of chromatography on a silver-impregnated column, and by combined GC-MS analysis and ozonolysis. Optimal catches of males were obtained with mixtures of (E)-8- and (Z)-8-dda in the range of 7030 to 3070.     

Individual variation in sex pheromone of smaller tea tortrix moth,Adoxophyes sp. (Lepidoptera: Tortricidae)

Female smaller tea tortrix mothsAdoxophyes sp. (Lepidoptera: Tortricidae), which initiated calling at 1, 2, or 3 days old, respectively, were analyzed individually for (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (Z)-9-tetradecenyl acetate (Z9–14: OAc) in the pheromone gland via GLC. Among different age groups, broad and similar distributions were found for pheromone quantity (¯X=58.6±52.9 ng/female; range 1.3–219.8 ng/female). The ratio of the two pheromone components averaged 6535 but ranged from 8416 to 4060. The significance of the pheromone blend variation to the attraction of males was tested in a field experiment. The ratio of males trapped by the most attractive blend versus the least attractive one was 2.2.     

Sex pheromone components of the blueberry leaftier mothCroesia curvalana kearfott (Lepidoptera: Tortricidae)

The GC-MS and GC-EAD analyses of sex-gland components and sex-gland-released volatiles have identified (E)- and (Z)-11-tetradecenal (9010) and (E)- and (Z)-11-tetradecenyl acetate (8515) as components of the sex pheromone chemical communication system ofCroesia curvalana (Kearfott). The aldehyde-to-acetate ratio of 91 was found in the gland-released components. This blend at a 0.1–1 g/day release rate from PVC lures was shown to be as effective as virgin females in the trapping of maleC. curvalana.     

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.     

Behavior of processionary males (Thaumetopoea pityocampa) induced by sex pheromone and analogs in a wind tunnel

The behavioral response of processionary males (Thaumetopoea pityocampa) to the natural pheromone (Z)-13-hexadecen-11-ynyl acetate (1) and structurally related analogs in a wind tunnel is presented. Stereomerically pureZ-1 and a mixture with theE isomer in 80:20 ratio elicited similar attraction responses at 1 µg and higher. The activity was dose-dependent, being optimum at 1 µg with 90% and 80% of males contacting with the source in the presence of theZ-1 andZ/E-1, respectively. 11-Hexadecynyl acetate (2) functioned as a pheromone mimic, being able to induce the complete mate-finding behavioral sequence, although its activity was much lower than that of the pheromone. (Z)-13-Hexadecen-11-ynyl alcohol (3) and, particularly, (Z)-13-hexadecen-11-ynal (4) were potent inhibitors of the upwind flight response in mixtures withZ-1 in 99:1, 95:5, and 91:9 ratios. (Z)-1,1,1-Trifluoro-16-nonadecen-14-yn-2-one (5) also inhibited the response of males to pheromone, particularly in the source contact behavior. Comparison with activity displayed by analogs in field tests is also reported.     

Sex pheromone components of the fruit-tree leaf roller,Archips argyrospilus (Walker) (Lepidoptera: Tortricidae), in British Columbia

In field experiments in the Okanagan Valley, British Columbia, the pheromone blend of (11Z)-tetradecen-1-ol acetate (Z11-14:OAc), (11E)-tetradecen-1-ol acetate (E 11-14:OAc), (9Z)-tetradecen-1-ol acetate (Z9-14:OAc) and dodecan-1-ol acetate (12: OAc) at a 1006421 ratio (western FTLR blend) attracted significantly more male fruit-tree leaf roller (FTLR),Archips argyrospilus (Walker), than did the previously reported four-component blend and modifications thereof. Addition of (11Z)-tetradecen-1-ol (Z11-14:OH) to the western FTLR blend in a ratio of 4% relative toZ11-14: OAc further significantly enhanced attraction. Compounds were identified and their ratio determined by coupled gas chromatographic-electroantennographic (GC-EAD) and coupled GC-mass spectrometric analyses of female FTLR pheromone gland extracts and by retention index calculations of candidate pheromone components. Determination and use of geographically specific pheromonal blends may be required for optimal, semiochemical-based biorational control of FTLR and other lepidopteran orchard pests.     

Effect of foliage proximity on attraction ofChoristoneura occidentalis andC. retiniana (Lepidoptera: Tortricidae) to pheromone sources

Pheromone-baited traps located close to both host and nonhost crowns were more attractive than traps located between crowns for bothC. occidentalis Freeman andC. retiniana (Walsingham) at both 10 m and at 1.5 m above the ground. At 10 m height, traps located in host foliage were more attractive than those located in nonhost foliage, but at 1.5m height there was no significant difference. These results were obtained for both dense and sparse populations ofC. occidentalis and sparse populations ofC. retiniana. We conclude that the tree species on which a virgin female is located is not an important factor restricting mating between closely relatedChoristoneura spp. Also, the tree species on which a trap is located may not be an important factor that must be standardized in developing pheromone monitoring systems forC. occidentalis andC. retiniana.     

Sex pheromone of the avocado pest,Amorbia cuneana (Walsingham) (Lepidoptera: Tortricidae)

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.This paper reports the results of research only. Mention of a commercial product in this paper does not constitute a recommendation by the U.S. Department of Agriculture.     

Behavioral responses of maleArgyrotaenia velutinana (Lepidoptera: Tortricidae) to components of its sex pheromone

Males of the redbanded leafroller,Argyrotaenia velutinana (Walker) (Lepidoptera: Tortricidae), were studied for their behavioral responses in laboratory olfactometers and in the field to the 3 components of the female-produced sex pheromone:cis-11-tetradecenyl acetate (c11–14Ac),trans-11-tetradecenyl acetate (t11–14Ac), and dodecyl acetate (12Ac). Dodecyl acetate, when evaporated with c11–14Ac (8%trans) in the field, modified the behavior of feral males nearby the chemical source, causing an increase in the frequency of landing and close approach to the pheromone dispenser. Apparently, an inflight behavioral modification concerning landing or not landing occurs within 60 cm of the source and is mediated by 12Ac. In laboratory olfactometers, c11–14Ac (8%trans) demonstrated a lower threshold for male activation than pure c11- and t11–14Ac and blends of the two isomers. Additionally, over a wide range of dosages, males responded with optimum wing-fanning response to c11–14Ac (8%trans) compared to pure c11–14Ac, c11–14:Ac (30%trans), and pure t11–14Ac, suggesting that thecistrans ratio rather than absolute amounts of either isomer, is a crucial factor in eliciting male response. When presented with c11–14Ac (8%trans) (11), dodecyl acetate caused a significant prolongation of wing-fanning over c11–14Ac (8%trans) alone and resulted in a greater percentage of males moving upwind to the source. Since the increase in wing-fanning and orientation occurred at higher concentrations of the 3-component mixture, the effect of 12Ac in the laboratory may reflect the close-range role of 12Ac in the field.     

Sex pheromone components of female smaller tea tortrix moth,Adoxophyes sp. (Lepidoptera: Tortricidae) in Taiwan

(Z)-11-Teiradecenyl acetate (Z11-14: Ac) and (Z)-9-tetrade-cenyl acetate (Z9–14: Ac) were isolated as major sex pheromone components from the female tips of the smaller tea tortrix moth,Adoxophyes sp., in Taiwan. The average amount ofZ11- andZ9–14: Ac in each female gland was 24.9 and 14.1 ng, in a ratio of 6436, respectively. When compared to a closely related Japanese strain, which used theZ9-14: Ac,Z11-14 Ac,E11–14:Ac, 10-Me-12:Ac four-component system (in a ratio of 633142), the Taiwan formulation of two components caught significantly more Taiwan males than the Japanese formulation of four components.     

Identification of a four-component sex pheromone of the female oriental fruit moth,Grapholitha molesta (Lepidoptera: Tortricidae)

The female-emitted pheromone ofGrapholitha molesta (Busck), the Oriental fruit moth, was collected by holding females in glass flasks during calling. Flask washes were found to contain four pheromone components: (Z)-8-dodecenyl acetate and (E)-8-dodecenyl acetate in a 1007 ratio, and (Z)-8-dodecen-1-ol and dodecanol in a 10020 ratio. The ratio of (Z)-8-acetate to (Z)-8-dodecen-1-ol was approx. 10030. Approximately 0.1–0.2 ng of pheromone was recovered per female per hour of calling.Published as Journal Article No. 8598 of the Michigan State University Agricultural Experiment Station.     

Sex pheromone ofPandemis heparana (Den. and Schiff.) (Lepidoptera:Tortricidae)

90% (Z)-11-tetradecen-1-yl acetate, 5% (Z)-9-tetradecen-1-yl acetate, 5% (Z)-11-tetradecen-1-ol, dodecyl acetate (<1%), and tetradecyl acetate (<1%) were identified from gland extracts ofPandemis heparana females by gas chromatography and gas chromatography-mass spectrometry analysis (including mass fragmentography studies), chemical characterization, total synthesis, laboratory and field bioassays. In the field, a mixture of (Z)-11-tetradecen-l-yl acetate and (Z)-9-tetradecen-l-yl acetate (955) was found to be essential for attractiveness ofP. heparana males.     

Biological evidence of an oviposition-deterring pheromone inLobesia botrana Den. et Schiff. (Lepidoptera,Tortricidae)

Females of the European grapevine moth (Lobesia botrana Den. et Schiff.) usually deposit isolated eggs on flowers and berries of the grapevine (Vitis vinifera L.). We have investigated whether an epideictic pheromone could be present on the egg surface to explain this spacing behavior. About 21,000 eggs ofL. botrana were washed in cold methanol, and the biological activity was tested in a two-choice bioassay offering treated and nontreated areas. Different dilutions of the extract were tested in methanol, which was inactive alone. At the dose of four egg equivalents per microliter of extract, the number of eggs laid by theL. botrana females was reduced by as much as 57% on the treated areas compared to nontreated areas. A longer-term suppression of oviposition (at least 24 hr) following an exposure to the extract occurred for two doses (0.6 and 4.0 eggs/l) of egg extract. Our results strongly suggest the occurrence of an oviposition-deterring pheromone (ODP) on the eggs ofL. botrana. The ecological value of these results is discussed.     

Female sex pheromone components of jasmine mothPalpita unionalis (Lepidoptera: Pyralidae)

(E)-11-Hexadecenal and (E)-11-hexadecen-1-yl acetate were found in abdomen tip extracts from females of the jasmine mothPalpita unionalis (Hübn). The identification was based on capillary GC analyses, mass spectrometry, and laboratory and field tests. In laboratory bioassays, both components elicited a low level of upwind flight by males. The two components when tested separately in the field were inactive, but the blend of the two components at a ratio of (3:7) was highly attractive to males. Traps baited with 1 mg of the two-component blend were competitive to traps baited with five virgin females. The addition of Z isomers components reduced male capture.     

Temporal patterns of sex pheromone titers and release rates inHolomelina lamae (Lepidoptera: Arctiidae)

Six hydrocarbon components (2-methylhexadecane,n-heptadecane, 2-methylheptadecane, 2-methyloctadecane,n-nonadecane, and 2-methylnonadecane) were identified in sex-pheromone gland extracts and in airborne collections ofHolomelina lamae. Low variability in the ratio of components among individuals indicates tight regulation of blend composition. Minor changes were evident in the quantity and ratio of the blend as a function of time of day. Based on gland extracts, the total quantity of the six components increased from day 1 (X = 6299 ng) to day 4 (X = 7498 ng) and subsequently decreased. No significant correlations were found between total gland contents and wet or dry weights of moths. Emission rates ofH. lamae females were determined from pheromone adsorbed onto Porapak Q. Quantities released peaked shortly after the onset of calling and decreased rapidly as calling continued. Peak release rates ranged from 13 to 350 ng/10 min, and from 37 to 835 ng/60 min. Noncalling females did not emit detectable quantities of pheromone. Based on release rates and the rate of pulsation of the abdominal tip, the average amount released per pulse is not constant. The mean ratio of components released (0.787.45 84.802.842.591.53) was not very different from the ratio of components in gland extracts of 2-day-old females (0.704.1990.12 1.651.911.42). We propose that the blend is atomized rather than volatilized from the gland, thus retaining nearly the same ratios in the female's effluvium as in her gland.     

Sex pheromone components of the spring hemlock looper,Lambdina athasaria (Walker) (Lepidoptera: Geometridae)

Two methylated hydrocarbons, 7-methylheptadecane (7) and 7,11-dimethylheptadecane (7,11), are female sex pheromone components of the spring hemlock looper (SHL),Lambdina athasaria (Walker). Compounds extracted from female pheromone glands were identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectrometry (GC-MS) in selected ion monitoring mode. In field trapping experiments, (7) and (7,11) by themselves were behaviorally inactive, but in combination attracted numerous male moths. (5,11)-Dimethylheptadecane (5,11) was detected in female SHL pheromone gland extracts, but did not enhance attraction to the binary blend of (7) and (7,11). The sex pheromone of SHL is related to that of congeneric eastern hemlock looper (EHL),Lambdina fiscellaria fiscellaria (Guen.) [(5,11) and 2,5-dimethylheptadecane (2,5)] and western hemlock looper (WHL),L.f. lugubrosa (Hulst) [(5,11), (2,5) and (7)]. Specificity of the pheromonal blend, spatial separation of coseasonal EHL and WHL, and temporal separation of sympatric EHL and SHL contribute to reproductive isolation.Dedicated to my father, Johannes Dinter, in honor of his 73th birthday.