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

Attraction of maleAgrotis 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 1/4ha 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.     

Geometric isomers of sex pheromone components do not affect attractancy of Conopomorpha cramerella in cocoa plantations

The cocoa pod borer (CPB), Conopomorpha cramerella (Snellen), sex pheromone was previously identified as a blend of (E,Z,Z)‐ and (E,E,Z)‐4,6,10‐hexadecatrienyl acetates and corresponding alcohols. These pheromone components were synthesized by modification of an existing method and the relative attractiveness of synthetic blends that included different levels of non‐target pheromone components and chemical purities was tested in a cocoa field using Delta traps. Male captures were not significantly different among traps baited with pheromone blends containing 5% to 47% (based on four identified pheromone components) of other geometric acetates [(E,Z,E)‐, (Z,Z,Z)‐, (Z,E,Z)‐ and (Z,E,E)‐4,6,10‐hexadecatrienyl acetates], indicating that C. cramerella males did not discriminate among the pheromone components and other geometric isomers in the blends. Therefore, neither antagonistic nor synergistic effects from other pheromone geometric isomers were observed. The modified synthetic pathway offers the prospect of more economical production of CPB sex pheromone. During 17 weeks when C. cramerella monitoring coincided with the main cocoa pod harvest period in 2013–2014, CPB trap catch data from some blends showed a good correlation with the number of pods with C. cramerella infestation symptoms.     

Sex pheromone components ofHeliothis maritima: chemical identification, flight tunnel and field tests

Three sex pheromonal components, (Z)-11-hexadecenal (Z11–16:Ald), (Z)-11-hexadecenol (Z11–16:OH), and hexadecanal (16:Ald), in a ratio of 88.0∶7.2∶4.8, were identified from ovipositor extracts of the fulvous clover moth,Heliothis maritima Grasl. (Lepidoptera: Noctuidae) by gas chromatographymass spectrometry. In addition, trace amounts of (Z)-9-hexadecenal (Z9–16:Ald) were detected in the extracts by GC. A blend of Z11–16:Ald, Z11–16:OH and 16:Ald in a ratio of 100∶6∶3, as well as in combination with 0.1 or 1 part Z9–16:Ald was tested at 0.01, 0.1, 1.0 and 10.0 μg doses in a flight tunnel. In flight tunnel tests male behavioral responses elicited by 0.1 or 1.0 μg doses of the 100∶6∶3∶1 blend were similar to those elicited by an ovipositor extract at 2 female equivalents. Deletion of Z9–16:Ald from the blend at 0.1 μg dose caused a decrease in the male response. In the field test, however, presence or absence of Z9–16:Ald did not significantly influence the number of males trapped in sticky traps with rubber septa containing 100 μg of the respective blends.     

The significance of blends of two sex pheromone components on the behavior of maleSpodoptera litura F. (Lepidoptera: Noctuidae)

Behavioral responses of maleSpodoptera litura to the female sex pheromone components, (Z, E)-9, 11-tetradecadienyl acetate (compound A) and (Z, E)-9, 12-tetradecadienyl acetate (compound B), and mixtures of compounds A and B were analyzed in the laboratory. Male orientation flight in a wind tunnel was induced by a lure dispenser onto which 1.1×10⁻³ ng of a mixture (A∶B=10∶1) was absorbed, while 1 ng of compound A was required to induced the same level of behavior. The blend ratio was important for trap catch and orientation flight of males and a 10∶1 mixture of compounds A and B was most effective. A mixture (10∶1) was more effective than compound A alone in induction of movement, walking, and flying in resting males in a glass tube. These results indicated that 2 sex pheromone components act as a set from the initial to final steps of male attraction to female.     

The Influence of Oviposition Experience on Response to Host Pheromone in Trichogramma sibericum (Hymenoptera: Trichogrammatidae)

Searching times and residence times of Trichogramma sibericum Sorokina were measured in the laboratory on individual cranberry leaves that had been treated with the sex pheromone of blackheaded fireworm [Rhopobota naevana (Hübner)] and on leaves that were left untreated. Mean searching time was higher on leaves treated by passive diffusion with either 50 or 100 g of the main component of fireworm pheromone, (Z)-11-tetradecen-1-ol acetate (Z11-14: Ac), than on control leaves. Mean residence times were also higher on leaves treated by passive diffusion with 50 g of Z11-14: Ac than on leaves untreated with pheromone. Pretrial oviposition experience in either the presence or the absence of host pheromone did not influence variation in searching time or residence time. This indicates that neither associative learning of the odor of host pheromone nor a more generalized increase in response to chemical stimuli after oviposition (priming) affects retention responses of T. sibericum to pheromone. Results are discussed in the context of current theories on the evolution of learning in insect parasitoids and as they relate to the concurrent use of pheromone-based mating disruption and releases of T. sibericum for pest management of the blackheaded fireworm.     

(Z)-9-tetradecenal: a potent inhibitor of pheromone-mediated communication in the oriental tobacco budworm moth,Helicoverpa assulta

The behavioural significance of (Z)-9-tetradecenal to male H. assulta was tested by comparing the number of moths attracted to lures containing a standard synthetic female sex pheromone with lures in which (Z)-9-tetradecenal was also added. The standard pheromone mixture used contained 1000 g (Z)-9-hexadecenal, 50 g (Z)-11-hexadecenal, 300 g (Z)-9-hexadecenyl acetate and 15 g (Z)-11-hexadecenyl acetate impregnated on rubber septa. Addition of (Z)-9-tetradecenal to the standard pheromone was shown to significantly reduce the caught of male H. assulta when added in amounts greater than 10 g or 1% of the major pheromone component in both field and net-house experiments. The reduction in catch was found to be dependent on the quantity of (Z)-9-tetradecenal added to the standard pheromone. The implications of these results on conspecific and inter-specific pheromone-mediated communication in H. assulta and related sympatric heliothine species is discussed.Abbreviations Z9-16:AL (Z)-9-hexadecenal - Z11-16:AL (Z)-11-hexadecenal - Z9-16:AC (Z)-9-hexadecenyl acetate - Z11-16:AC (Z)-11-hexadecenyl acetate - Z9-14:AL (Z)-9-tetradecenal - Z9-16:OH (Z)-9-hexadecen-1-ol - Z11-16:OH (Z)-11-hexadecen-1-ol - RH relative humidity     

Selection for altered pheromone-component ratios in the pink bollworm moth,Pectinophora gossypiella (Lepidoptera: Gelechiidae)

Female pink bollworm moths, Pectinophora gossypiella(Saunders), were selected for altered component ratios of the long-distance sex pheromone, (Z, E)-and (Z, Z)-7,11- hexadecadienyl acetate. Selection for 12 generations increased the mean (± SD) percentage of the (Z, E)isomer from 42.9 ± 1.0 in the parental generation to 48.2 ± 1.2. Although statistically significant, a change of this magnitude may be transparent to males because of their relatively broad response spectrum. Selection for a lower percentage of the (Z, E)isomer yielded no change in the mean pheromone ratio. The total amount of pheromone produced declined in both selected lines. In the line selected for females producing a high percentage of the (Z, E)isomer, the duration of wing fanning by males to high (Z, E)blends was elevated.     

Novel Antifouling and Antimicrobial Compound from a Marine-Derived Fungus Ampelomyces sp.

In this study, using a bioassay-guided isolation and purification procedure, we obtained 3-chloro-2,5-dihydroxybenzyl alcohol from a marine-derived Ampelomyces species that effectively inhibited larval settlement of the tubeworm Hydroides elegans and of cyprids of the barnacle Balanus amphitrite. The inhibitive effect on larval settlement was nontoxic and the EC₅₀ of 3-chloro-2,5-dihydroxybenzyl alcohol ranged from 3.19 μg ml⁻¹ to 3.81 μg ml⁻¹ while the LC₅₀ was 266.68 μg ml⁻¹ for B. amphitrite cyprids; EC₅₀ ranged from 0.67 μg ml⁻¹ to 0.78 μg ml⁻¹, and LC₅₀ was 2.64 μg ml⁻¹ for competent larvae of H. elegans, indicating that inhibitive effect of this compound was nontoxic. At a concentration of 50 μg per disc, this compound showed strong inhibitive effects on the growth of 13 out of 15 marine bacterial species tested in disc diffusion bioassay. Overall, the high inhibitory activities against bacteria and larval settlement as well as the non- or low-toxic nature of this compound to the barnacle and polychaete larvae suggest this compound could be a potent antifoulant and/or antibiotic.     

Spatial discrimination of pheromones and behavioural antagonists by the tortricid moths Cydia pomonella and Adoxophyes orana

Male moths responding to their species-specific sex pheromone, may cease their upwind flight when pheromone components of sympatric species are added to the mixture. The interspecific interaction between the pheromone response of the tortricid moths Cydia pomonella and Adoxophyes orana was investigated in field-trapping and wind-tunnel studies. Addition of the A. orana pheromone [(Z9)-tetradecenylacetate and (Z11)-tetradecenylacetate] to a source containing the C. pomonella pheromone [(E8, E10)-dodecadienol] resulted in a significant inhibition of attraction by male C. pomonella. It is demonstrated that this behavioural antagonist for C. pomonella must be emitted from the same point source to induce this inhibitory effect. A spatial separation of the two interspecific pheromones (at 14 cm, 5 cm and 0.5 cm crosswind) restored the attraction of the conspecific pheromone for male C. pomonella. In contrast to C. pomonella, male A. orana were not inhibited by point sources releasing both the C. pomonella and A. orana pheromone. We suggest that the discrepancy in the interspecific pheromone interaction between these two tortricids can be explained if we consider the evolutionary ecology of interspecific pheromone communication in C. pomonella and A. orana. Accepted: 18 July 1999     

Evaluation of Zostera detritus as a potential new source of zosteric acid

Detritus of the seagrasses Zostera noltii and Z. marina collected on the beaches of Arcachon Lagoon (France) over a 3-year period was screened as a new source of zosteric acid (ZA). This natural sulphated phenolic acid is a high value-added product capable of preventing settlement of marine organisms and protecting crops from fungal diseases. The seasonal variation of the ZA content was quantified in methanolic and aqueous crude extracts using high-performance liquid chromatography. The concentration found ranged from 65 to 456 μg g⁻¹ dry wt for Z. noltii and 51–692 μg g⁻¹ dry wt for Z. marina, respectively. This is the first report of ZA in Zostera noltii. Detrital leaves of Zostera have never before been screened for their bioactive substances. These results show that this low cost, very abundant and renewable, but heretofore unused, marine resource has potential as a source of a rare and naturally occurring bioactive product.     

Autodetection and chemistry of female and male pheromone in both sexes of the tiger moth Panaxia quadripunctaria

Female moths of Panaxia quadripunctaria PODA (Lepidoptera, Arctiidae), produce (Z,Z)-6,9-heneicosadiene (I) as the major and (Z,Z)-6,9-eicosadiene (II) as the minor component of a putative pheromone. Related compounds occur in trace amounts. The abdominal scent glands contain 5–10 μg of (I) and 50–100 ng of (II). Recordings of electroantennogram (EAG) responses to (I), (II), and to female glands are of equal amplitude in both sexes. Females are thus capable of pheromone autodetection in contrast to the majority of moths where females are considered to be anosmic for their own attractant. The EAG threshold to (I) was below 1 ng at the odour source. The odour of the male scent gland (corema) elicited significant EAGs in both sexes. The chemical contents of coremata varied with the provenience of the moths. A variety of ethyl esters was always found, yet hydroxydanaidal (up to 20 μg/corema) and traces of danaidal, only in some samples. All these scents might be components of a male pheromone. Peculiar scent scales on the coremata are exposed during the extrusion. Antennae of both sexes have similar inventories of trichoid sensilla. Accepted: 11 July 1997     

Behaviour of male oriental fruit moth, Grapholita molesta, in overlapping sex pheromone plumes in a wind tunnel

The behaviour of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) males was studied in overlapping sex pheromone plumes in a wind tunnel. The ultimate aim of the study was to assess the effect of different treatments on male behaviour and consider the observed changes within the context of the suggested mechanisms underlying mating disruption. Two baits were placed either in series or parallel using both synthetic pheromone blends and female extracts. One bait, the reference containing (Z)-8-dodecenyl acetate/(E)-8-dodecenyl acetate/(Z)-8-dodecenol in a ratio of 100/6/10 was kept constant at a dose of 100 g of the main component, giving a composition and a release rate close to that of a female. The dose of the other bait varied between 0.1 and 100 times the concentration of the reference and was a mixture of one, two or three pheromone components. Males clearly discriminated between different blends and doses in the overlapping plumes, for regardless if the lures were presented in series or in parallel they followed the complete plume. Complete suppression of the response to the reference was only achieved with 300 g of the optimal three-component blend on the other lure. When tested singly, a bait consisting of Z8-12:OAc/E8-12:OAc/Z8-12:O Hin a 100/0.2/0.4 ratio, attracted a high proportion of the males when placed 75 cm upwind of the male release site, but no males from 150 cm. Our data suggest that complete pheromone blends should be more effective than any incomplete blends in mating disruption formulations for G. molesta.     

Isolation and identification of antimicrobial agent-producing bacterium from <Emphasis Type="Italic">Taxus baccata</Emphasis> rhizosphere antagonistic against clinically significant microbes

A bacterium identified as Pseudomonas fluorescence was isolated from Taxus baccata rhizosphere. Ethyl acetate extract from its culture filtrate yielded an active antimicrobial compound that was purified by TLC. The active metabolites were resolved by column chromatography on silica gel (60–120 mesh). The compound was further characterized on the basis of spectral data (UV, IR and ¹HNMR), which indicated the presence of an aromatic ring and phenolic functionality. The compound showed significant antimicrobial activity against two-gram positive bacteria (B. subtilis and S. aureus), four-gram negative bacteria (E. coli, K. pneumoniae, S. flexneri and P. aeruginosa), and one pathogenic fungus (Candida albicans). The minimum inhibitory concentration (MIC) of the compound ranged between 75μg to 250 μg/ml.     

Sex pheromone traps for monitoring the codling moth: effect of dispenser type, field aging of dispenser, pheromone dose and type of trap on male captures

The effects of dispenser type, dispenser aging in the field, pheromone dose in the dispenser and trap type on trapping efficiency of codling moth,Cydia pomonella (L.), males were investigated in Israel. An Israeli-manufactured rubber septum was significantly better than the CM Pherocon cap in attracting males to a Pherocon 1C cap trap or an IPS trap. The effect of aging of the dispenser in the field on trapping efficiency was significant in CM Pherocon caps and the Israeli septa. Captures in traps were negatively correlated with aging of septa. The effect of aging of dispensers was more marked during summer than during spring. The fairly rapid loss of attractancy indicates that the lures should be replaced after 2 weeks at the most. The release rate of the pheromone from the dispensers was measured in a flow system. The emission from the Israeli septa and Pherocon caps decreased sharply after 2 weeks and then was almost constant, which explains the lower attractancy of aged septa. However, there was a marked difference in the release profiles of the pheromone from the two types of dispensers, which may explain the different performance of the two dispensers. Within the range of 0.1 to 100 μg pheromone per dispenser, male response increased positively with the pheromone dose. Pheromone loadings of 100 or 1000 μg per dispenser did not differ significantly in their attractiveness for males. A load of 5000 μg per dispenser was significantly less attractive to males than was 100 or 1000 μg per dispenser. The non-sticky IPS trap was significantly better in capturing codling moth males than was the sticky, commonly used Pherocon 1C trap, provided it was baited with the Israeli dispenser. The two traps were equally effective when baited with the CM Pherocon caps. The possibility of using the non-sticky, nonsaturating and easy-to-handle IPS traps for monitoring codling moth is of great importance. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan 50-250, Israel. No 3702-E, 1992 series.     

Responses of male winter moths (Operophtera brumata) to their sex attactant (3Z,6Z,9Z)-1,3,6,9 nonadecatetraene and to some structural analogues

Conclusion (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene, the synthetic sex pheromone of the female of O. brumata is highly active in attracting males of this species in the field (Germany and Switzerland). No analogous compounds possessing attractivity to O. brumata males have been found up to now, nor did they show any inhibitory effects to the same species.Therefore (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene (I) can be recommended as a good attractant in the prognosis or monitoring of this lepidopteran pest.     

Identification and functional characterization of sex pheromone receptors in beet armyworm Spodoptera exigua (Hübner)

In moths, males can detect a distinct blend of several pheromone components by specialized olfactory receptor neurons (ORNs) on the antennae. Four candidate pheromone receptors (PR) with seven transmembrane domains were identified by homology cloning from the antennae of Spodoptera exigua (Sexi). Phylogenetic analyses reveal that all four odorant receptors (OR) belong to pheromone receptor subtypes. Expression patterns revealed that PRs were male-specific in the antenna except for SexiOR11, which was female antenna-biased. Functional analyses of these PRs were conducted using heterologous expression in Xenopus oocytes. SexiOR13 and SexiOR16 were all broadly activated by multiple pheromone components. SexiOR13 responded robustly to the critical pheromone component, Z9, E12-14:OAc and the minor pheromone component, Z9-14:OAc at a concentration of 10^?4 M. Dose-response studies indicate that SexiOR13 was approximately 4 times more sensitive to Z9,E12-14:OAc (EC50 = 3.158 × 10^?6 M) compared to Z9-14:OAc (EC50 = 1.203 × 10^?5 M). While, SexiOR16 responded robustly to the secondary pheromone component Z9-14:OH with high sensitivity (EC50 = 9.690 × 10^?7 M). However, similar tests of the five pheromones with SexiOR6 and SexiOR11 failed to elicit any response. These results provide basic knowledge to further advance research on the molecular mechanisms of pheromone reception.     

Chemical communication in termites: syn-4,6-dimethylundecan-1-ol as trail-following pheromone, syn-4,6-dimethylundecanal and (5E)-2,6,10-trimethylundeca-5,9-dienal as the respective male and female sex pheromones in Hodotermopsis sjoestedti (Isoptera, Archotermopsidae)

The trail-following pheromone and sex pheromones were investigated in the Indomalayan termite Hodotermopsis sjoestedti belonging to the new family Archotermopsidae.Gas chromatography coupled to mass spectrometry (GC–MS) after solid phase microextraction (SPME) of the sternal gland secretion of pseudergates and trail-following bioassays demonstrated that the trail-following pheromone of H. sjoestedti was syn-4,6-dimethylundecan-1-ol, a new chemical structure for termite pheromones. GC–MS after SPME of the sternal gland secretion of alates also allowed the identification of sex-specific compounds. In female alates, the major sex-specific compound was identified as (5E)-2,6,10-trimethylundeca-5,9-dienal, a compound previously identified as the female sex pheromone of the termite Zootermopsis nevadensis. In male alates, the major sex-specific compound was identified as syn-4,6-dimethylundecanal, a homolog of syn-4,6-dimethyldodecanal, which has previously been confirmed as the male sex pheromone of Z. nevadensis. The presence of sex-specific compounds in alates of H. sjoestedti strongly suggests for this termite the presence of sex-specific pairing pheromones which were only known until now in Z. nevadensis. Our results showed therefore a close chemical relationship between the pheromones of the taxa Hodotermopsis and Zootermopsis and, in contrast, a clear difference with the taxa Stolotermes and Porotermes, which is in total agreement with the recent creation of the families Archotermopsidae and Stolotermitidae as a substitute for the former family Termopsidae.     

A two-component sex attractant for males of the geometrid moth Alsophila quadripunctata

The binary mixture of the hydrocarbons (3Z,6Z,9Z)-3,6,9-nonadecatriene and (6Z,9Z)-6,9-nonadecadiene is a sex attractant for males of Alsophila quadripunctata Esp. (Lepidoptera, Geometridae). Triene/diene ratios from 1:1 to 1:0.01 attracted males in the field, the ratios 1:1 and 1:0.7 were most effective. The triene on its own also attracted males, but in significantly lower numbers than the 1:1 mixture. In a dosage test the highest dose, 1800 g of 1:0.8 [triene:diene] mixture applied to rubber caps was most effective. This is the first report of a geometrid sex attractant with field activity containing more than one component.

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Zusammenfassung Die binäre Mischung der Kohlenwasserstoffe (3Z,6Z,9Z)-3,6,9-Nonadecatrien [ZZZ3,6,9-19:H] und (6Z,9Z)-6,9-Nonadecadien [ZZ6,9-19:H] in den Verhältnissen 1:1 bis 1:0.01 erwies sich im Freiland als Sexuallockstoff für Männchen von Alsophila quadripunctata (Geometridae, Lepidoptera). Dabei besaß die 1:1-Mischung die beste Fängigkeit, das Nonadecatrien allein lockte schlechter, während das C₁₉-Alkadien unwirksam war. Ein Dosiswirksamkeitstest ergab bei Köderbeladungen von 1.8 mg (Trien:Dien + 1:0.8) die besten Fangergebnisse. Im Verlauf der Untersuchungen wurden weitere zwölf geometrische-oder positionsisomere C₁₉-Polyenkohlenwasserstoffe getestet, wobei keine der geprüften Verbindungen Attraktant-oder Inhibitorwirkung zeigte.

     

Synergistic effect between dieckol from <Emphasis Type="Italic">Ecklonia stolonifera</Emphasis> and β-lactams against methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

We have been attempting for some time to discover a compound evidencing antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The dieckol isolated from Ecklonia stolonifera has been shown to exhibit antibacterial activity against methicillin-susceptible S. aureus (MSSA) and MRSA. The minimum inhibitory concentrations (MICs) of dieckol were determined in a range of 32 to 64 μg/mL against standard MSSA and MRSA strains. Furthermore, dieckol clearly reversed the high-level ampicillin and penicillin resistance of MRSA. The MICs of ampicillin against two standard strains of MRSA were dramatically reduced from 512 to 0.5 μg/mL in combination with 1/4 MIC of dieckol (16 μg/mL). The fractional inhibitory concentration (FIC) indices of ampicillin and penicillin were measured from 0.066 to 0.266 in combination with 8 or 16 μg/mL of dieckol against all tested MRSA strains, thereby suggesting that dieckol-ampicillin or dieckol-penicillin combinations exert a synergistic effect against MRSA. The results of this study indicate that dieckol, administered in combination with β-lactams, may prove effective in the treatment of MRSA infections. Our finding may also contribute to the development of an alternative phytotherapeutic anti-MRSA agent.