Oviposition response ofLobesia botrana females to long-chain free fatty acids and esters from its eggs

Avoidance of occupied ovisposition sites supposes that females perceive information related to their own progency. Fatty acids identified from egg extracts have been reevaluated using a different extraction method, and we have investigated the dose-dependent oviposition response of European grape vine moths (Lobesia botrana) to myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, methyl palmitate, methyl oleate, and ethyl palmitate; all except ethyl palmitate have been identified from eggs ofL. botrana. A methylene dichloride extract of eggs fromL. botrana revealed the presence of saturated free fatty acids (myristic, palmitic, and stearic) and unsaturated acids (palmitoleic, oleic, linoleic, and linolenic) in amounts ranging from 3.9 ng/egg equivalent for myristic acid to 30 ng/egg equivalent for palmitic and oleic acids. The extract also contained traces of methyl palmitate and methyl stearate. The greatest avoidance indexes were observed in response to palmitic, palmitoleic, and oleic acids. All the other compounds tested caused weaker responses. A reduction in the number of eggs laid was observed when moths were exposed to each of the esters applied at 0.3 µg per application spot. Reduction in eggs laid was also observed at a 10-fold higher dose of oleic acid. The present results confirm that general and simple molecules can be involved in the regulation of oviposition site selection and that they may participate in chemical marking of the eggs.     

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.     

Electrophysiological and field activity of halogenated analogs of (E,E)-8,10-dodecadien-1-ol,the main pheromone component,in codling moth (Cydia pomonella L.)

Pest monitoring and control of the codling moth,Cydia pomonella L., have been developed using the main pheromone component of this species, (E,E)-8,10-dodecadienol (codlemone). However, the activity of codlemone is not satisfactory for pest control by mating disruption. Thus, we have synthesized halogenated analogs of codlemone to see if they could be used as new agents for pest control of the codling moth. Their biological activity was measured by electrophysiological techniques. In EAG screening, codlemone was the most active compound. F(10,11)-codlemone [(E,E)-10,11-difluoro-8,10-dodecadienol] and Cl-codlemone [(E,E)-11-chloro-8,10-undecadienol] elicited significant EAG responses, F(10,11)-codlemone triggering responses not significantly different from responses to codlemone. EAG cross-adaptation experiments and single sensillum recordings revealed that these compounds were detected by the same receptor neuron type as codlemone. No competitive inhibition with codlemone was observed from nonactive compounds. In field trapping, F(10,11)-codlemone and Cl-codlemone were more attractive to male codling moths than codlemone itself. Possible explanations of this activity are discussed.     

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.     

Application of sex attractants for monitoring the pea moth,Cydia nigricana (F.) (Lepidoptera: Tortricidae)

The use of sex attractants to monitor the pea moth,Cydia nigricana (F.) in the United Kingdom is decribed. Two systems are currently available: one for use in combining (dry-harvested) peas for human consumption or seed, and one for use in vining peas for freezing or canning. The development and details of both systems are reviewed and their commercial application discussed.     

Sex pheromone biosynthesis of (E,E)-8,10-dodecadienol in codling mothCydia pomonella involvesE9 desaturation

Sex pheromone biosynthesis in the codling mothCydia pomonella (Lepidoptera; Tortricidae) was studied by topical application of deuterated fatty acids in DMSO to pheromone glands. The incorporation of deuterium label into fatty acids and alcohols in the pheromone gland was monitored by gas chromatography with flame ionization detection and mass spectrometry in the selected ion monitoring mode. Dodecanol, (E)-9-dodecenol, (E,E)-8,10-dodecadienol, tetradecanol, and hexadecanol were found in gland extracts. The application of [12,12,12-²H₃]dodecanoic acid resulted in labeled dodecanol, (E)-9-dodecenol, and (E,E)-8,10-dodecadienol, as well as the corresponding labeled acids. No label was incorporated into tetradecanol or hexadecanol or any acid with more than 12 carbon atoms. The application of labeled tetradecanoic or hexadecanoic acid introduced label not only into the 12-carbon alcohols, but also into tetradecanol, or tetradecanol and hexadecanol, respectively. The application of (E)-[11, 11,12,12,12,-²H₅]9-dodecen-oic acid, whose facile synthesis is described, resulted in labeled (E)-9-do-decenol and (E,E)-8,10-dodecadienol. The (E,E)-8,10-dodecadienol so produced was characterized by an ion atm/z 186, equivalent to [M]⁺ of a dienol labeled with four deuterons. Thus, one deuterium label is lost when the labeled (E)-9-monoene is converted to the (E,E)-8,10-diene. We conclude that (E,E)-8,10-dodecadienol is synthesized by chain shortening (-oxidation) of palmitic acid to dodecanoic acid, followed by an unusualE9 desaturation and subsequent conversion of this intermediate into the conjugated precursor, which is finally reduced to the pheromone alcohol. The evolutionary significance ofE9 desaturation being responsible for pheromone production in an Olethreutinae species is discussed.     

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.     

Solvent effects on conformation of a sex pheromone ofCydia (Laspeyresia pomonella L.; Lepidoptera: Tortricidae: Olethreutinae), codlemone (8,10-dodecadienol)

The conformations of codlemone (8,10-dodecadienol) and of a model analog have been studied by CNDO calculations. Stable conformations are found for the folded forms when the polarity of the solvent is taken into account.     

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 0.1–100,000g. 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 10g, response increased from 0 to about 80% and then was approximately constant from 10 to 300g. Over the range 0.1–300g, the percentage of males contacting the septum was virtually the same as the percentage flying upwind. From 300 to 100,000g, 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 0.3g to 26% at a dose of 30g and then decreased to 0% at a dose of 3000g. Thus, the inhibiting effect of the isomers on response was greater at the higher doses.     

Biosynthesis of sex pheromone components and glycerolipid precursors from sodium [1-14C]acetate in redbanded leafroller moth

Sodium [1-¹⁴C]acetate in water-dimethyl sulfoxide (11) was applied topically to sex pheromone glands ofArgyrolaenia velutinana. Radiolabel was incorporated into the pheromone components (Z)-11-tetradecenyl acetate and (E)-11-tetradecenyl acetate, and also into triacylglycerols, diacylglycerols, ethanolamine phosphatides, and choline phosphatides. In the triacylglycerols, radiolabel appeared in (Z)-11-tetradecenoate, (E)-11-tetradecenoate, tetradecanoate, hexadecanoate, and octadecanoate. In the choline phosphatides, the same acyl moieties incorporated radiolabel but at lower levels. In the diacylglycerols and ethanolamine phosphatides, only the radiolabel in hexadecanoate and octadecanoate was above the limit of detection. At different times following application of sodium [1-¹⁴C]acetate, the relative proportions of labeled (Z)-11-tetradecenyl acetate and (E)-11-tetradecenyl acetate changed very little, but the relative proportions of labeled fatty acyl moieties in the triacylglycerols and choline phosphatides changed markedly. After 8 min, triacylglycerols had incorporated about equal amounts of radiolabel into (Z)-11-tetradecenoate, (E)-11-tetradecenoate, and tetradecanoate. As the incubation time was increased, triacylglycerols accumulated proportionately more radiolabeled (E)-11-tetradecenoate than (Z)-11-tetradecenoate, and accumulated proportionately less radiolabeled tetradecanoate. In the choline phosphatides, at all times of incubation the amount of radiolabel incorporated into (Z)-11-tetradecenoate was small but above the limit of detection, and the amounts of radiolabel in (E)-11-tetradecenoate and tetradecanoate were smaller and often below the limit of detection. In both the triacylglycerols and the choline phosphatides, the relative proportion of radiolabeled hexadecanoate decreased with time, and that of octadecanoate increased.     

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 European grapevine moth (Lobesia botrana) its chemical transformations in sunlight and heat

Photo- and radical isomerization of (E, Z)-7,9-dodecadien-1-yl acetate (DDA) leads to an equilibrium mixture of all four possible geometric isomers of 7,9-DDA in the ratio ofE,E, 69–76%;Z,E, 11–13%;E, Z, 12–15%; andZ, Z, 1–3%. Iodine catalysis of the isomerization takes place even in dark at room temperature and is probably a radical reaction.     

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).     

Calling behavior and pheromone titer in the smaller tea tortrix moth,Adoxophyes sp. (Lepidoptera: Tortricidae)

The calling behavior and pheromone titer in the female smaller tea tortrix moth,Adoxophyes sp., were investigated under a 1410-hr light-dark photoperiod. Quantitative gas chromatographic analysis of ovipositor extract for (Z)-11-tetradecenyl acetate (Z11–14Ac) and (Z)-9-tetradecenyl acetate (Z9–14Ac), the major pheromone components of this species, obtained on the third day postemergence, indicated that extractable amounts of sex pheromone were present throughout the period of observation. Maximal pheromone titer and calling activity was reached at 8 and 10 hr after onset of scotophase, respectively. The ratio ofZ11–14Ac toZ9–14Ac through the 24-hr period varied significantly. The significance of the sex pheromone component ratio variation on 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 2.16.     

Responses of male codling moths (Laspeyresia pomonella) to codlemone and other alcohols in a wind tunnel

The primary pheromone (E,E)-8,10-dodecadien-1-ol (I, codle-mone), 11 further alcohols, and binary blends of both were evaluated for attractiveness as defined by the percentage ofL. pomonella males showing oriented upwind flight terminated by landing at the source within 10 min after release. Sources of I were attractive from 10^–5 g to 10¹ g, with approx. 70% males responding at 10^–3–10^–1 g. Most other alcohols also showed attractiveness, but the dose-response curves differed greatly with respect to the range of effective lure doses as well as the maximum response level reached at any dose. (E,E)-7,9-Undecadien-1-ol (III) revealed a dose-response curve similar in shape to I but shifted towards higher concentrations. (E,E)-8,10-Tridecadien-1-ol (II) and (E)-8,10-undecadien-1-ol (IV) exhibited threshold values of 10^–5 g (same as for I) and were effective over, respectively, seven and nine decades of source load, but they did not reach a response level of 40% at any test amount. (E)-9,11-Dodecadien-1-ol (VI) and the monoenes (E)-8-, (E)-10-, and (Z)-10-dodecen-1-ol (VIII-X) showed weak attractivity restricted to one to three test doses. Upwind approaches that broke off a few centimeters from the source were rarely seen in tests with I but frequently occurred with some of the analogs. When combined with 10^–3 g of I, all alcohol analogs showed inhibitory properties, although the amounts required to obtain a significant lowering of response differed by up to 10⁵-fold. This amount was the lowest (10^–4 g) for the positional isomer VI, and the highest (10¹ g) for undecan-1-ol (XI) and dodecan-1-ol (XII). With some mixtures, the presence of the inhibitor appeared to cause an alteration in landing behavior. No synergistic effects were seen in these tests. The results are briefly considered with respect to the sensory perception of the test stimuli and the involvement of minor components in the female pheromone blend.     

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.     

Male moth sensitivity to multicomponent pheromones: Critical role of female-released blend in determining the functional role of components and active space of the pheromone

In the present study male redbanded leafroller (Argyrotaenia velutinana), cabbage looper (Trichoplusia ni), and Oriental fruit moths, (Grapholita molesta), were tested in a flight tunnel to (1) the major pheromone component, (2) theZ/E pheromone component mixtures for Oriental fruit moth and redbanded leafroller, (3) and the female-released blends, over a series of dosages. Experiments were designed to test the hypothesis that male response downwind of a female is initiated by the major component and that minor components function only to elicit behaviors close to the female during close-range approach and courtship. The results did not support this hypothesis, but rather showed that males initiated upwind flight in significantly higher percentages to the complete blends of components, at all dosages, compared to single components or partial blends. Addition of minor components also signficantly enhanced male perception of the major component at lower dosages, resulting in completed flights to dosages of the major component that alone did not elicit any upwind flight. Our results support the concept that minor components function to enhance male sensitivity to the pheromone, and the specificity of the signal. Our results also support the hypothesis that the active space of the pheromone is a function of the upper and lower concentration thresholds for the blend of components, and not simply for the major component.     

Fatty acid composition of French infant formulas with emphasis on the content and detailed profile oftrans fatty acids

The aim of the present study was to identify and quantitatetrans isomers of C18 fatty acids in some French infant formulas. Twenty powdered infant formulas were purchased in pharmacies and supermarkets in order to assess theirtrans mono- and poly-unsaturated fatty acids content. The fatty acid profiles were examined using methyl and isopropyl ester derivatives. The combination of gas-liquid chromatography, high-performance liquid chromatography, and silver nitrate thin-layer chromatography was needed to describe the detailed fatty acid compositions of the samples, includingtrans isomers of unsaturated C18 fatty acids. All the samples containedtrans isomers of C18∶1 acid (mean level 1.97±0.28% of total fatty acids), with vaccenic acid being generally the major isomer (15 out of 20 samples), thus indicating the origin from bovine milk. All the formulas also contained various isomers of linoleic and α-linolenic acids, but at lower levels.Trans PUFA isomers are the same as those present in deodorized oils. In conclusion, all the infant formulas analyzed in this study contained sometrans fatty acids, including isomers of essential fatty acids. This should be taken into account in the dietary intake of the newborn.     

Residual activity of oviposition-deterring pheromone inRhagoletis pomonella (Diptera: Tephritidae) and female response to infested fruit

Under dry conditions, oviposition-deterring pheromone (ODP) of the apple maggot fly (Rhagoletis pomonella Walsh) on host fruit proved deterrent to ovipositing females for at least three weeks, with a half-life of ca. 11 days. There was no difference in decline of residual activity under lab vs. field conditions or between fly-deposited ODP vs. an application of a water extract of ODP. A decline in pheromone activity resulted from exposure to both natural and simulated rainfall. For natural rainfall, greatest losses (50– 61%) in activity resulted from high-intensity rains, with substantially less activity lost (13–35%) following light or moderate intensity rains.R. pomonella females discriminated against fruit without ODP but with conspecific larvae. Discrimination against infested fruit was manifested within fewer days following infestation of small fruit (9 mm diam.) as compared to larger fruit (15 mm diam.).     

Response of male eye-spotted bud moth,Spilonota ocellana (Lepidoptera: Tortricidae), to different pheromone blends in north America and The Netherlands

Response of male eye-spotted bud moth,Spilonota ocellana (Denis and Schiffermüller), to different ratios of synthetic sex pheromone components, (Z)-8-tetradecenyl acetate (Z8-14:OAc) and (Z)-8-tetradecenyl alcohol (Z8-14:OH), were compared in four North American locations and in one location in The Netherlands. In British Columbia, Nova Scotia, Michigan, and The Netherlands, a 99:1 blend ofZ8-14:OAc andZ8-14:OH captured significantly more maleS. ocellana thanZ8-14:OAc alone or binary blends containing 10–50%Z8-14:OH. In Ontario, where population sizes were low compared to the other four locations, trends in trap catches were similar, and there was no indication that maleS. ocellana responded differently to the tested pheromone blends. A 99:1 blend ofZ8-14:OAc andZ8-14:OH should be most effective in pheromone-based control programs ofS. ocellana in North America and in The Netherlands. Our results confirm earlier studies that a 99:1 blend ofZ8-14:OAc andZ8-14:OH captures significantly more maleS. ocellana thanZ8-14:OAc alone. However, our finding that a 99:1 blend ofZ8-14:OAc andZ8-14:OH is significantly more attractive than binary blends containing 10–50%Z8-14:OH differs from previous findings in Germany and Switzerland.Agriculture Canada Summerland Research Station Contribution No. 821.