Field Trapping Experiments Research Articles

Asymmetric semiochemical-mediated interactions of Monochamus spp. (Coleoptera: Cerambycidae) and associated bark beetles in Portugal and Canada.

Some coniferophagous bark and woodboring beetles overlap spatially and temporally in host trees. These larval interactions have been classified as competitive and predatory in favor of the larger and more mobile woodborer larvae. In some bark beetles, larval traits have been reported that facilitate evasion of woodborer larvae. Both bark beetles and woodborers mediate mating on host material with volatile pheromones. Although it is known that some woodborers eavesdrop on bark beetle aggregation pheromones to facilitate host location, it is not known what effect woodborer pheromones have on bark beetles. The pheromone monochamol is used by most Monochamus spp. Dejean and coniferophagous species from this genus co-occur with bark beetles in host tissues. Because of the negative consequences these larval interactions have for bark beetles, we hypothesized that the woodborer pheromone monochamol would inhibit captures of sympatric and synchronic bark beetles to intercept traps baited with their aggregation pheromones and host volatiles. We tested this hypothesis in 2 systems, 1 in Ontario, Canada, and another in Setúbal, Portugal with field trapping experiments. Trap captures of Ips sexdentatus (Boerner) (Coleoptera: Scolytinae), Orthotomicus erosus (Wollaston) (Coleoptera: Scolytinae) (2 bark beetle species captured in Portugal), and Ips pini (Say) (Coleoptera: Scolytinae) (1 bark beetle species captured in Canada) were reduced by the presence of monochamol. These results suggest that an additional evasion mechanism in some bark beetles is the detection of the woodborer pheromone monochamol and subsequent reduced response to aggregation pheromone and host volatiles in the presence of this woodborer pheromone.

Response of hibiscus mealybug (Hemiptera: Pseudococcidae) to citrus volatiles induced by mechanical injury.

Hibiscus mealybug, Nipaecoccus viridis (Newstead) (Hemiptera: Pseudococcidae), is a recent invasive pest of citrus and many other crops in Florida. Nipaecoccus viridis attacks all above ground parts of citrus trees and heavy infestation can cause leaf drop and premature abortion of developing fruits. We quantified greater captures of N. viridis in cardboard band traps on areas of citrus trees that were intentionally injured by mechanical rasping of epidermal tissues as compared with similar but uninjured citrus branches. Direct field collection of headspace volatiles from mechanically injured or intact citrus branches revealed both qualitative and quantitative differences. Certain volatiles (γ-terpinene, citronellal, citronellyl acetate, β-E-farnesene, α-humulene, and α-E-E-farnesene) were only present in samples from damaged citrus branches. Behavioral assays using a laboratory Y-tube olfactometer revealed attraction of N. viridis to volatiles associated with mechanical damage of citrus including synthetic β-ocimene, γ-terpinene, sabinene, isomers of farnesene, and citronellal when loaded into lures at either of 2 concentrations (0.01 or 0.1 µg/µl). Subsequent field trapping experiments confirmed increased captures of various life stages of N. viridis in cardboard band traps baited with a 10.0 µg/µl concentration of farnesene:ocimene:sabinene blend (in 7:13:17 ratio), as well as those releasing either farnesene or ocimene alone at this same concentration, as compared with the mineral oil (diluent) negative control. Our results indicate that common plant related terpenes released by citrus following mechanical damage may be useful for development of an effective monitoring trap for N. viridis.

Identification and field verification of the aggregation pheromone components produced by male Holotrichia parallela Motschulsky (Coleoptera: Scarabaeidae).

The chafer beetle, Holotrichia parallela, causes damage to numerous economically significant crops worldwide. Adult beetles exhibit aggregation behavior likely mediated by a male-produced pheromone. Advancements in biological research technology have facilitated the identification of insect aggregation pheromones and promoted their applications as bait for trapping and monitoring pests. Currently, only a few active components of aggregation pheromones from Holotrichia species have been identified. However, the specific components of aggregation pheromones produced by H. parallela remain unknown. In this study, we initially observed from Y-tube olfactometer assays that both male and female H. parallela were significantly attracted to volatiles emitted by males, but not to those from females. We then collected hindgut crude extracts of male adults and carried out gas chromatography-mass spectrometry analysis to identify potential aggregation pheromone components. Pentadecyl acetate, cis-13-docosenol, and behenic acid were identified as male-specific compounds in comparison to female extracts, serving as components of the aggregation pheromone in H. parallela. We further evaluated their attractiveness to H. parallea in both laboratory and field experiments. In laboratory settings, pentadecyl acetate, cis-13-docosenol, and behenic acid evoked significant responses to both males and females at specific concentrations, as evidenced by both electroantennography tests and behavioral bioassays. Under field conditions, traps baited with these three compounds captured significantly more H. parallela adults compared to control traps. In this study, we found that pentadecyl acetate, cis-13-docosenol, and behenic acid are specifically present in male H. parallela, serving as aggregation pheromones. Both laboratory and field-trapping experiments suggest their potential as monitoring and controlling tools against H. parallela adults. © 2024 Society of Chemical Industry.

Inhibitory activity of some short-chain aliphatic aldehydes on pheromone and ammonium carbonate-mediated attraction in olive fruit fly, Bactrocera oleae.

The olive fruit fly (OFF), Bactrocera oleae (Rossi), is the main insect pest of olive trees worldwide. Legislation limits to the use of some synthetic larvicidal insecticides is leading to the development of new control options for preventive control of adult flies. In the present study, the biological activity of four short-chain aliphatic aldehydes, namely hexanal, (E)-2-hexenal, heptanal and (E)-2-heptenal, previously reported as repellents to the OFF adults was investigated. Electroantennography (EAG) recordings showed that antennae of OFF males and females are able to perceive the test compounds in a wide range of doses. In field trapping experiments, reservoir-type polypropylene (PP) membrane dispensers loaded with individual compounds did not elicit a significant attraction of OFF males and females. On the contrary, a significant reduction of male catches was noticed when sex pheromone dispensers and PP membrane dispensers, loaded with one of the test compounds, were applied on the same white sticky traps ≈20 cm apart. Likewise, male and female catches in yellow sticky traps baited with ammonium carbonate (AC) dispensers as food attractant were significantly reduced by the presence of PP membrane dispensers of individual aliphatic aldehydes on the same traps. In small plots control trials, solid formulations of the four aldehydes into a bentonite clay support induced a significant reduction of the OFF active infestation mainly when C6 and C7 aldehyde-activated bentonites were used. Short-chain aliphatic aldehydes showed inhibitory effects on sex pheromone and food attractant-mediated attraction of OFF. Results of field trials suggest potential of short-chain aliphatic aldehydes to develop new semiochemical-based OFF control options. © 2024 Society of Chemical Industry.

Confirmation that Monochamol is a Male Produced Aggregation-Sex Pheromone for Monochamus maculosus Haldeman (Coleoptera: Cerambycidae).

The recognition of cerambycids as frequent and damaging invaders led to an increase in the interest in the chemical ecology of the group with the identification of pheromones and pheromone-like attractants for well over 100 species. Pheromone components of the Cerambycidae are often phylogenetically conserved, with a single compound serving as a pheromone component for several related species. In the subfamily Lamiinae, the compound 2-(undecyloxy)ethanol (monochamol) has been identified as an aggregation-sex pheromone for several species of the genus Monochamus. In other species, including Monochamus maculosus Haldeman, field trials have demonstrated that monochamol is a pheromone attractant, but at that point it was still unknown as to whether it was a pheromone for this species. Here we report the identification, and laboratory and field trials of a pheromone component produced by adult male M. maculosus. Chemical analyses of headspace volatile collections sampled from field collected beetles of both sexes revealed the presence of one male-specific compound that was identified as 2-(undecyloxy)ethanol. Electroantennography analyses showed that monochamol elicited responses from the antennae of female beetles. Traps baited with monochamol in the field captured M. maculosus adults of both sexes corroborating the identification of monochamol as the sex-aggregation pheromone of this species. The attractivity of monochamol to adult M. maculosus in our field trapping experiment was synergized by the addition of the host volatile α-pinene.

Identification of the Sex Pheromone of the Asparagus Moth, Parahypopta Caestrum (Lepidoptera, Cossidae)

Chemical, electrophysiological, and field trapping experiments were carried out to identify the female-produced sex pheromone of the asparagus moth, Parahypopta caestrum, a very serious pests of asparagus cultivations in southern Europe. Gas chromatography coupled with mass spectrometry and electroantennogram detection (GC-MS-EAD) analysis of hexane and solid-phase microextraction (SPME) extracts of sex pheromone glands of calling females consistently detected four compounds eliciting EAG responses in male moth antennae. According to their GC retention times, mass spectra, and comparative EAG analyses with reference standards, these EAD-active compounds were identified as (Z)-9-tetradecenol (Z9-14:OH), (Z)-5-tetradecenyl acetate (Z5-14:Ac), (Z)-7-tetradecenyl acetate (Z7-14:Ac), and (Z)-9-tetradecenyl acetate (Z9-14:Ac), respectively. In the SPME extracts from the head-space of individual abdominal tips, Z9-14:Ac, Z5-14:Ac, Z7-14:Ac, and Z9:14 OH were detected in the ratio of 82:9:5:4. In EAG dose-response experiments, Z9-14:Ac was the strongest antennal stimulant at different doses tested. In field trapping experiments, Z9-14:Ac, Z7-14:Ac, and Z5-14:Ac proven to be essential for male attraction and a their 85:5:10 blend loaded onto green rubber septum dispensers was significantly more effective than single-, two-, and any other three-component blend of these compounds. The addition of Z9-14:OH to the optimal blend resulted in a significant reduction of male catches. The attractive blend here identified allowed for an effective and accurate monitoring of P. caestrum flight activity in southern Italy.

Identification, synthesis, and field evaluation of components of the female-produced sex pheromone of Helopeltis cinchonae (Hemiptera: Miridae), an emerging pest of tea.

Helopeltis cinchonae (Hemiptera: Miridae) is a major pest of tea plantations in Asia. Conventional control of pests with pesticides is unsustainable. Therefore, safe and eco-friendly alternatives, such as pheromones, are required to manage the pest. In gas chromatography-electroantennographic detection (GC-EAD) analysis of whole-body extracts of virgin female H. cinchonae, two compounds elicited electroantennogram (EAG) responses from male antennae. These were identified as hexyl (R)-3-acetoxybutyrate and (R)-1-acetoxy-5-butyroxyhexane using gas chromatography-mass spectrometry (GC-MS) analysis compared to synthetic compounds. This is the first study to report 1-acetoxy-5-butyroxyhexane as an insect pheromone component. The synthetic compounds elicited dose-dependent EAG responses from the antennae of male H. cinchonae. In two field trapping experiments, the individual compounds were highly attractive to male H. cinchonae when dispensed from polyethylene vials. However, higher catches were obtained with blends of the two compounds in a 1:10 ratio. The blend of racemic compounds was as attractive as the blend of (R)-enantiomers. We reported that 1-acetoxy-5-butyroxyhexane and hexyl 3-acetoxybutyrate are components of the female-produced sex pheromone of H. cinchonae, but further work is required on the blend and loading of pheromone and on trap design to provide an optimized system for monitoring and control of this pest. The results may also facilitate the identification of the pheromones of other Helopeltis species, which are major pests in many crops. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of dose and trap type on captures of striped and spotted cucumber beetles using synthetic vittatalactone.

Striped cucumber beetle, Acalymma vittatum (F.) and spotted cucumber beetle (Diabrotica undecimpunctata howardi Barber) are key pests of cucurbits. Pesticide applications directed against cucumber beetles can jeopardize bee pollination which is essential to crop yield. Alternative selective tactics, including behavioral control for managing cucumber beetles, are needed in order to improve pest management. The striped cucumber beetle pheromone vittatalactone is attractive to both male and female adults, and also to spotted cucumber beetles. We tested the response of both species to different doses of synthetic vittatalactone, and to different trap types, in field trapping experiments in Maryland. Both species showed strong dose-response in May-June and October 2020. Among 12 trap types tested during a 2-wk experiment in June, using 1 mg mixed vittatalactone, sticky panel traps caught the most of each species, with vittatalactone-baited traps exceeding unbaited traps by >8 fold for striped and >2 fold for spotted, and with significant response to yellow versus clear color absent in striped, but strong in spotted. Among nonsticky traps, those with yellow or yellow-green exceeded those without these colors for both beetle species, and a ground-placed boll weevil trap captured the most striped cucumber beetles. Bucket-style traps caught excessive nontarget bumblebees (Bombus spp.) if yellow, and a few beetles, if all green. Results allow field monitoring with a choice of sticky or nonsticky traps and suggested lure loading of 1 mg mixed vittatalactone, containing ~90 μg active isomer. These findings contribute to the development of multispecies behavioral monitoring and control as a component of cucurbit IPM.

Identification and Field Bioassay of Rusicada privata (Lepidoptera: Erebidae) Sex Pheromone

Rusicada privata (Lepidoptera: Erebidae) is a major pest insect on Hibiscus syriacus L. (Malvaceae: Malvales), which is usually planted in urban landscapes. Insecticidal control of R. privata is not ideal for urban landscaping due to its harmful effects and risk to human health. Therefore, nonchemical and ecofriendly alternatives are needed. To identify the sex pheromone of R. privata, abdominal tip extracts of male and female R. privata were analyzed by gas chromatography-mass spectrometry. The abundance of 7-methylheptadecane (7Me-17Hy) in female R. privata abdominal tip extracts led us to hypothesize that it is the major sex pheromone. The compound was tentatively identified by a mass spectral library and confirmed by matching retention times and mass spectra of the female-produced compound with those of a synthetic standard. The compounds elicited electroantennographic (EAG) activity. In a field trapping experiment, only synthetic lures containing 7Me-17Hy attracted R. privata males. The EAG activity and field trapping results confirmed that 7Me-17Hy is the sex pheromone of female R. privata. The results will aid in developing sex pheromone-based R. privata control techniques, such as mating disruption.

Semiochemicals produced by fungal bark beetle symbiont Endoconidiophora rufipennis and the discovery of an anti-attractant for Ips typographus.

Bark beetles vector symbiotic fungal species into their host trees during mass attacks. The symbiotic relationship with blue stain fungi of the Ascomycetes, including genera of Endoconidiophora (syn. = Ceratocystis), promotes successful establishment whereby the microbes help to overcome the host trees' defence and degrade toxic resins. This is the first study to evaluate both the volatile emissions from an insect-associated blue stain fungus over time and the insect response in a field trapping experiment. Volatile emissions from isolates of Endoconidiophora rufipennis (ER) were collected by solid-phase microextraction (SPME) and analysed by gas chromatography-mass spectroscopy (GC-MS) over a period of 30 days. This virulent North American fungus is closely related to E. polonica, a symbiotic fungus known from Eurasian spruce bark beetle Ips typographus.Nine volatiles were emitted by ER in substantial amounts: isoamyl acetate, sulcatone, 2-phenethyl acetate, geranyl acetone, geranyl acetate, citronellyl acetate, (R)- and (S)-sulcatol, and (R)-sulcatol acetate. A late peaking compound was geranyl acetone. In the field trapping experiment, three of the fungal volatiles (geranyl acetone, 2-phenethyl acetate and sulcatone) were tested in combination with a synthetic aggregation pheromone for I. typographus. Traps with geranyl acetone attracted lower numbers of I. typographus compared to traps with 2-phenethyl acetate, sulcatone or the pheromone alone as a control. The results showed that geranyl acetone acts as an anti-attractant and may act naturally on I. typographus as a cue from an associated fungus to signal an overexploited host.

Synthesis and field experiments of the female sex pheromone of sweet potato weevil, Cylas formicarius

Abstract. (Z)-3-dodecen-1-yl (E)-2-butenoate (1) identified as the sex pheromone of sweet potato weevil, Cylas formicarius Fabricius, had been synthesized successfully from 3-butyn-1-ol and 1‑bromooctane as the starting materials. The overall yield via four steps was 60% calculated on 3-butyn-1-ol. The primary step of the scheme was the stereoselective reduction reaction for alkyne cis-hydrogenation without using molecular hydrogen by Pd2(dba)3-catalyzed. And, this reaction was carried out efficiently with KOH/DMF as the hydrogen source. Next, the field trapping experiments were conducted from February to June 2021 at Tien Thuy ward - Chau Thanh district (Ben Tre province) to develop a simple, easy to construct, cost‐effective, and efficient sex pheromone‐baited trap. Main experiments have given positive results such as the relative to sweet-potato foliage, the trap designs, doses of pheromone lure from 0.1 mg to 0.8 mg, and the effect of lure traps with a dose of 0.4 mg. These values can use well to control the dosage of pheromone in field experiments. Keywords: (Z)-3-dodecen-1-yl (E)-2-butenoate, Cylas formicarius Fabricius, Pd2(dba)3/KOH/DMF, 1-decyne, 1-bromooctane, 3-butyn-1-ol, (Z)-configuration, the average number of captured individuals, sweet potato weevil.

Sex Attractant Blend for Dioryctria mongolicella (Lepidoptera: Pyralidae) in the Northeast of China

Abstract The Mongolian pine borer, Dioryctria mongolicella Wang & Sung (Lepidoptera: Pyralidae), is a major pest in Mongolian pine (Pinus sylvetris L. var. mongolica Litvinov) plantations in the northeast of China. A blend of 11-hexadecenal and 11-hexadecenyl acetate in a ratio of 2:1 was detected from extracts of its female sex pheromone glands by gas chromatography–mass spectrometry. Our field trapping experiments confirmed that the D. mongolicella pheromone consists of a blend of (E)-11-hexadecenal (E11-16:Ald) and (Z)-11hexadecenyl acetate (Z11-16:Ac). The addition of (Z,E)-9,11-tetradecadienyl acetate (Z9E11-14:Ac) and (Z,Z,Z)-3,6,9-tricosatriene (ZZZ3,6,9-23:H) increased catches of male D. mongolicella in sticky traps baited with E11-16:Ald and Z11-16:Ac. However, the addition of (3Z,6Z,9Z,12Z,15Z)-pentacosapentaene or (Z,Z,Z,Z,Z)-3,6,9,12,15-tricosapentaene to lures loaded with E11-16:Ald, Z11-16:Ac, and Z9E11-14:Ac did not significantly increase trap catches of D. mongolicella at two locations in Heilongjiang province, China. The synthetic blend of 400 µg E11-16:Ald, 200 µg Z11-16:Ac, 200 µg Z9E11-14:Ac, and 500 µg ZZZ3,6,9-23:H will help in developing efficient strategies for monitoring and control of D. mongolicella populations in Mongolian pine plantations.

Identification of (E)‐ and (Z)‐11‐tetradecenyl acetate as sex pheromone components of the currant pest Euhyponomeutoides albithoracellus

AbstractThe currant bud moth Euhyponomeutoides albithoracellus is a destructive pest in black currant orchards in Northern Sweden and Finland. The larvae feed on the buds, and at high densities, the species can cause severe yield losses. Sex pheromone components of the bud moth were identified via solvent extraction of excised female pheromone glands, analyses by gas chromatography with electroantennographic detection and gas chromatography–mass spectrometry and field trapping experiments. Antennae of males responded strongly and consistently to two compounds in extracts, identified as (E)‐11‐tetradecenyl acetate and (Z)‐11‐tetradecenyl acetate. Weaker and less consistent responses were observed to the corresponding alcohols, (E)‐11‐tetradecenol and (Z)‐11‐tetradecenol, and tetradecyl acetate. Field tests showed strong attraction of bud moth males to a 1:1 blend of (E)‐11‐tetradecenyl acetate and (Z)‐11‐tetradecenyl acetate. Adding the alcohols to the binary acetate blend reduced trap catches drastically, whereas tetradecyl acetate had no statistically significant impact on male attraction when added to that binary blend. Finally, testing different compositions of the binary acetate blend revealed highest catch in traps baited with a 25:75 or 50:50 ratio of the E:Z acetate isomers. The identification of sex pheromone components of the bud moth contributes to developing sustainable control of this pest via monitoring and mating disruption with sex pheromone.

Asian corn borer (Ostrinia furnacalis Gn., Lepidoptera: Crambidae): Attraction to a bisexual lure and comparison of performance with synthetic sex pheromone

AbstractHost plant-derived semiochemicals are becoming the most promising attractants to lure corn borers to traps in the field. Following success with the European corn borer (Ostrinia nubilalis), a two-component blend bisexual lure (phenylacetaldehyde and 2-(4-methoxyphenyl)ethanol) of the host plant odor was tested in wind tunnel and field trapping experiments on the Asian corn borer (Ostrinia furnacalis) (ACB). To be able to compare the lure's performance with synthetic pheromone, a new route for the sex pheromone components (Z)-12-tetradecenyl acetate and (E)-12-tetradecenyl acetate was also developed, and the biological activity of the products was confirmed. The bisexual lure attracted both males and females of ACB in laboratory wind tunnel, and also in the field. Field trapping results indicated that traps with the bisexual lure attracted somewhat more ACB (both sexes) than pheromone baited traps, but this indication needs further confirmation. Traps baited with the bisexual lure may offer a new tool for monitoring ACB for practical purposes.

Both the Squash Bug Anasa tristis and Horned Squash Bug Anasa armigera (Hemiptera: Coreidae) are Attracted to Vittatalactone, the Aggregation Pheromone of Striped Cucumber Beetle.

Vittatalactone, the aggregation pheromone of the striped cucumber beetle, Acalymma vittatum (F.) (Coleoptera: Chrysomelidae), is attractive to two species of squash bugs (Hemiptera: Coreidae), the squash bug Anasa tristis (DeGeer) and horned squash bug Anasa armigera (Say). In field trapping experiments in Maryland and Virginia, clear sticky traps baited with 1 mg of a synthetic 8-isomer mix of vittatalactone captured ~9× more of female A. tristis and of both sexes of A. armigera, whereas male A. tristis were not significantly attracted, compared to unbaited traps. A. armigera showed a distinct dose-response to vittatalactone lure loading in the late season, and this species was more attracted than A. tristis, based on comparison to captures from underneath wooden boards emplaced in adjacent fields. Results suggest that vittatalactone could be a 'keystone semiochemical' in colonization of cucurbit hosts by specialist herbivores, and may offer the opportunity for multi-species behavioral control as a component of integrated pest management in cucurbit crops.

Identification of the Sex Pheromone of the Pink Grass Worm, Tmetolophota atristriga, Reveals Possible Population Differences in Male Response to Sex Pheromone

The pink grass worm, Tmetolophota atristriga (Walker), is an endemic New Zealand noctuid moth species that is abundant throughout the North and South Islands. The larvae are minor defoliators of agricultural pasture. We investigated the sex pheromone of this species. Analysis of extract of the female sex pheromone gland identified six compounds: two monounsaturated compounds, (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-11-hexadecenyl acetate (Z11-16:Ac), three saturated compounds, hexadecanal (16:Ald), hexadecyl acetate (16:Ac) and octadecan-1-ol (18:OH), and a triene hydrocarbon, (3Z,6Z,9Z)-tricosatriene (Z3Z6Z9-23:Hy). Several field-trapping experiments testing combinations of the six compounds were conducted. Results suggested that males of two different populations of T. atristriga responded differently to different blends of the compounds. Males of one population responded equally to a two-component blend as to other blends, including the one with all six compounds. By contrast, males of the second population responded only to the six-component blend or a ternary blend of Z11-16:Ald, Z11-16:Ac and Z3Z6Z9-23:Hy. In experiments testing different doses of Z11-16:Ald and Z11-16:Ac in a binary or a six-component blend, a 1 mg dose of the binary blend gave the greatest male catch for both populations. This is the second sex pheromone identification of a New Zealand species of Noctuidae and is the first reported occurrence of Z3Z6Z9-23:Hy as a sex pheromone component of any noctuid species.

Ophiostomatoid fungi synergize attraction of the Eurasian spruce bark beetle, Ips typographus to its aggregation pheromone in field traps.

Eurasian spruce bark beetle, Ips typographus is a destructive pest of the Norway spruce (Picea abies). Recent outbreaks in Europe have been attributed to global warming and other anthropogenic impacts. Bark beetles are guided by multiple complex olfactory cues throughout their life cycle. Male-produced aggregation pheromones, comprising 2-methyl-3-buten-2-ol and cis-verbenol, have been identified as the most powerful attractants for dispersing conspecifics. In addition to host trees, bark beetles interact with multiple organisms, including symbiotic ophiostomatoid fungi, which may promote beetle colonization success and offspring development. Previously, in a short-distance laboratory assay, we demonstrated that I. typographus adults are attracted to the volatile organic compounds (VOCs) produced by three symbiotic fungi: Grosmannia penicillata, Endoconidiophora polonica, and Leptographium europhioides. Furthermore, the abundant fusel alcohols and their acetates were found to be the most attractive odorants in the fungal VOC profile. In this study, using a long-distance field-trapping experiment, we analyzed the role of fungal VOCs as attractants for dispersing I. typographus. Two types of fungal lures were tested in combination with pheromones in traps: (1) live cultures of fungi grown on potato dextrose agar (PDA) and (2) dispensers containing synthetic fusel alcohols and their acetates in equal proportions. Subsequently, the composition of VOCs emitted from live fungal lures were analyzed. We found that the symbiotic fungi synergistically increased the attraction of beetles to pheromones in field traps and the attractiveness of live fungal lures depended on the fungal load. While one Petri dish with E. polonica, when combined with pheromones synergistically increased trapping efficiency, three Petri dishes with L. europhioides were required to achieve the same. The synthetic mix of fungal fusel alcohols and acetates improved the catch efficiency of pheromones only at a low tested dose. VOC analysis of fungal cultures revealed that all the three fungi produced fusel alcohols and acetates but in variable composition and amounts. Collectively, the results of this study show that, in addition to pheromones, bark beetles might also use volatile cues from their symbiotic fungi to improve tree colonization and reproductive success in their breeding and feeding sites.

Development of a Kairomone-Based Attractant as a Monitoring Tool for the Cocoa Pod Borer, Conopomorpha cramerella (Snellen) (Lepidoptera: Gracillariidae).

Simple SummaryWe have investigated the efficacy of five potential kairomone attractants for the cocoa pod borer (CPB) in Indonesia. Among them, the organic lychee flavor extract in a primitive formulation was the most attractive and was competitive with the commercial pheromone lures. An improved kairomone lure formulation based on specialty membrane and the concentrated extracts captured as many CPB males during a 4-week period and was significantly active for as long as 28 weeks. The long-life pheromone lure may be particularly useful in monitoring large-scale cocoa farms and developing new mitigation technologies that would necessitate high longevity powerful attractants. It should provide a cheaper alternative to the pheromone lures.The cocoa pod borer (CPB), Conopomorpha cramerella, is a major economic pest of cocoa, Theobroma cacao, in Southeast Asia. CPB monitoring programs currently use a costly synthetic pheromone lure attractive to males. Field trapping experiments demonstrating an effective plant-based alternative are presented in this study. Five lychee-based products were compared for their attractiveness to CPB males. The organic lychee flavor extract (OLFE), the most attractive product, captured significantly more CPB as a 1 mL vial formulation than unbaited traps, while being competitive with the commercial pheromone lures. Additional experiments show that a 20 mL membrane OLFE lure was most effective, attracting significantly more CPB than the pheromone. When the kairomone and pheromone lures were combined, no additive or synergistic effects were observed. Concentrating the OLFE product (OLFEc) using a rotary evaporator increased the lure attractiveness to field longevity for up to 28 weeks; in contrast, pheromone lures were effective for approximately 4 weeks. The 20 mL concentrated OLFE membrane lures should provide a cheaper and more efficient monitoring tool for CPB than the current commercial pheromone lures.

Efficacy of nanocapsules loaded with Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) sex pheromone as evaluated in wind tunnel and field trapping experiments

Efficacy of nanocapsules loaded with Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) sex pheromone as evaluated in wind tunnel and field trapping experiments

Identification of a unique three-component sex pheromone produced by the tea black tussock moth, Dasychira baibarana (Lepidoptera: Erebidae: Lymantriinae).

The tea black tussock moth Dasychira baibarana Matsumura is a devastating pest in tea plantations that causes substantial economic losses. Presently, there is no effective method to control this pest other than pesticide application. The identified sex pheromone of D. baibarana could be used for detecting and monitoring this pest. Gas chromatography-electroantennogram detection showed that D. baibarana male moth antennae responded strongly to three components in the female sex pheromone gland, which were identified as: (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene (Z3,Z6,epo9-21:H) (I), (3Z,6Z,11E)-cis-9,10-epoxyhenicosa-3,6,11-triene (Z3,Z6,epo9,E11-21:H) (II) and (3Z,6Z)-henicosa-3,6-dien-11-one (Z3,Z6-21:11-one) (III). Dasychira baibarana uses a unique composition of an epoxydiene, epoxytriene, and dienone with the same 3,6-dienyl motif as its sex pheromone. The epoxytriene and dienone were not previously characterized as insect pheromone components. Electroantennogram analysis showed that each synthetic compound strongly stimulated male antennae, and compounds II and III elicited stronger responses than compound I. A wind tunnel bioassay and field trapping experiments proved that, ternary blends of compounds I-III attracted D. baibarana. Efficient attraction was achieved with a rubber septum baited with 500 μg of a mixture of compounds I-III at the ratio 25:20:55. The three identified compounds elicited an electroantennogram response in D. baibarana male moth antennae, and a mixture of the three components at the ratio 25:20:55 attracted D. baibarana male moths in a wind tunnel assay and field trapping experiments. This blend could be used for integrated management of D. baibarana in tea plantations. © 2022 Society of Chemical Industry.