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Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a serious polyphagous pest of various field and horticultural crops. A complete knowledge on the morphological features of antennal sensory structures is essential for efficient semiochemical-based control methods. The external structure and distribution of antennal sensilla in male and female adults of H. armigera were investigated using scanning electron microscopy. Eight distinct morphological types of sensilla were identified in both sexes: sensilla trichodea, sensilla basiconica, sensilla auricillica, sensilla coeloconica (multiporous), sensilla chaetica (uniporous), sensilla styloconica, sensilla squamiformia, and Böhm sensilla (aporous) in varying numbers and distribution along the length of the antennae. Of these sensilla, the most widespread are sensilla trichodea and sensilla basiconica on the antennae of both sexes. Female antennae have comparatively greater number of sensilla trichodea than male antennae. Among eight types of sensilla, sensilla basiconica, auricillica, styloconica type II, squamiformia, and Böhm sensilla were identified and reported for the first time in H. armigera. Sexual dimorphism in H. armigera was mainly detected as the variations in sensilla shape, numbers, and distribution of each type of sensilla. The sexual difference was observed in the numbers of sensilla coeloconica, chaetica, styloconica, and squamiformia per flagellomere. The possible functions of these sensilla were discussed in view of previously reported lepidopteran insects. The findings provide fundamental information on the morphology and distribution of antennal sensory structures in H. armigera. It would be useful for further detailed studies on physiological and behavioral function of each sensillum type and helpful for formulating related pest control methods.

Responses to sex pheromones are commonly antagonized by pheromone components of closely related species. Pheromone antagonism has not been widely explored for phylogenetically distant species that have completely different pheromone components. Yet, pheromone components of sympatrically occurring species may also interfere with each other even if these species are distantly related. Here, the effects of heterospecific pheromones on electrophysiology (electroantennogram, EAG) and behavioral responses were tested on the diamondback moth Plutella xyloslella (Plutellidae) and two sympatric noctuid moth species, Spodoptera litura and Spodoptera exigua, whose larvae also feed on Brassica crops.The sex pheromone blend of P. xyloslella, and its components, did not elicit EAG responses in males of the two noctuid species, while sex pheromone components of the noctuid moths elicited significant EAG responses in P. xyloslella males. In wind tunnel bioassays, both (Z, E)-9, 12-tetradecadienyl acetate (ZE-9,12-14:OAc) and (Z, E)-9, 11-tetradecadienyl acetate (ZE-9,11-14:OAc), sex pheromone components from the noctuid moths, inhibited the upwind flight behavior of P. xyloslella males toward an intraspecific pheromone odor source. In Brassica fields, sex pheromone lures of P. xyloslella did not influence trap catches of the noctuid moths, while P. xyloslella pheromone lures baited with either ZE-9,11-14:OAc or ZE-9,12-14:OAc decreased trap catches of P. xyloslella males in a dose-dependent manner. Trap catches of P. xylostella males were also affected by the proximity of ZE-9,11-14:OAc or ZE-9,12-14:OAc to P. xylostella lures.The uni-directional pheromone antagonism by ZE-9,11-14:OAc and ZE-9,12-14:OAc suggests innovative semiochemical-based strategies for the management of P. xyloslella and other economically important pests in Brassica fields. © 2021 Society of Chemical Industry.

Semiochemical use is a promising way to reduce damage from pests by improving natural control in agro-ecosystems. The aphid alarm pheromone (E)-β-farnesene (EβF) and herbivore-induced methyl salicylate (MeSA) are two volatile cues to induce changes in aphid behavior with functional significance. Because of limitations related to the volatility and oxidization of EβF and MeSA under natural conditions, slow-release and antioxidant techniques should be developed and optimized before application. Here, a slow-release alginate bead of EβF mixed with MeSA was first designed and manufactured. We hypothesized that a mixture of these two semiochemicals could be effective in controlling Sitobion miscanthi in wheat crops. Both MeSA and EβF in alginate beads were released stably and continuously for at least 15 days in the laboratory, whereas EβF in paraffin oil and pure MeSA were released for only 2 and 7 days, respectively. In 2018 field experiments, EβF and MeSA alone or in association significantly decreased the abundance of alate and apterous aphids. An increased abundance of mummified aphids enhanced by higher parasitism rates was observed when using EβF and MeSA in association, with a significant reduction of apterous abundance, more so than EβF or MeSA alone. In 2019, plots treated with a mixture of EβF and MeSA showed significantly decreased abundance of alate and apterous aphids with higher parasitism rates compared with the control. The new slow-release alginate bead containing a mixture of EβF with MeSA could be the most efficient formulation to control S. miscanthi population by attracting parasitoids in the wheat agro-ecosystem. © 2021 Society of Chemical Industry. © 2021 Society of Chemical Industry.

Long-term pest insect monitoring in agriculture and forestry has advanced population ecology. However, the discontinuation of research materials such as pheromone lure products jeopardizes data collection continuity, which constrains the utilization of the industrial datasets in ecology. Three pheromone lures against the smaller tea tortrix moth Adoxophyes honmai Yasuda (Lepidoptera; Tortricidae) were available but one was recently discontinued. Hence, a statistical method is required to convert data among records of moths captured with different lures. We developed several generalized additive mixed models (GAMM) separating temporal fluctuation in the background male density during trapping and attenuation of lure attractiveness due to aging or air exposure after settlement. We collected multisite trap data over four moth generations. The lures in each of these were unsealed at different times before trap settlement. We used cross-validation to select the model with the best generalization performance. The preferred GAMM had nonlinear density fluctuation terms and lure attractiveness decreased exponentially after unsealing. The attenuation rates varied among lures. A light trap dataset near the pheromone traps was a candidate for a male density predictor. Nevertheless, there was only a weak correlation between trap yields, suggesting the difficulty of data conversion between the traps differing in attraction mechanisms.

1. Significant research has been devoted to the development of semiochemical repellents for mountain pine beetle Dendroctonus ponderosae Hopkins. Several formulations of the beetle's antiaggregation pheromone verbenone (4,6,6‐trimethylbicyclo[3.1.1]hept‐3‐en‐2‐one) are registered to protect pine trees and stands. 2. We compared the efficacy of verbenone and Verbenone Plus for protecting individual lodgepole pine Pinus contorta Dougl. ex Loud. and small stands of P. contorta from mortality attributed to D. ponderosae . Verbenone Plus is a blend of semiochemicals [(−)‐verbenone, acetophenone, and (E )‐2‐hexen‐1‐ol + (Z )‐2‐hexen‐1‐ol] originally developed to inhibit aggregation of western pine beetle D. brevicomis LeConte. It is the only effective semiochemical repellent that protects ponderosa pine P. ponderosa Dougl. ex Laws. from mortality attributed to D. brevicomis , but has yet to be registered or commercialized. 3. Both verbenone and Verbenone Plus were effective for protecting individual P. contorta and small stands of P. contorta from mortality attributed to D. ponderosae . Verbenone alone was as effective as Verbenone Plus. 4. An obstacle to the broader use of semiochemical repellents for the management of bark beetles is the relatively high cost and specificity of the semiochemicals involved. A semiochemical repellent with efficacy across multiple bark beetle species and hosts, such as Verbenone Plus, would be desirable, assuming the additional components are not cost‐prohibitive or limit registration.

There is increasing evidence that microorganisms emit a wide range of volatile compounds (mVOCs, microbial volatile organic compounds) that act as insect semiochemicals, and therefore play an important role in insect behaviour. Although it is generally believed that phylogenetically closely related microbes tend to have similar phenotypic characteristics and therefore may elicit similar responses in insects, currently little is known about whether the evolutionary history and phylogenetic relationships among microorganisms have an impact on insect‐microbe interactions. In this study, we tested the hypothesis that phylogenetic relationships among 40 Bacillus strains isolated from diverse environmental sources predicted mVOC composition and the olfactory response of the generalist aphid parasitoid Aphidius colemani . Results revealed that phylogenetically closely related Bacillus strains emitted similar blends of mVOCs and elicited a comparable olfactory response of A. colemani in Y‐tube olfactometer bioassays, varying between attraction and repellence. Analysis of the chemical composition of the mVOC blends showed that all Bacillus strains produced a highly similar set of volatiles, but often in different concentrations and ratios. Benzaldehyde was produced in relatively high concentrations by strains that repel A. colemani , while attractive mVOC blends contained relatively higher amounts of acetoin, 2,3‐butanediol, 2,3‐butanedione, eucalyptol and isoamylamine. Overall, these results indicate that bacterial phylogeny had a strong impact on mVOC compositions and as a result on the olfactory responses of insects.

The host selection behaviour of the walnut twig beetle, Pityophthorus juglandis , was assessed by monitoring the landing rates of the beetles with sticky sheet traps on the host and nonhost hardwood branches. Sticky sheet traps were deployed for 8 weeks from 6 June to 2 August. 2017 in the Putah Creek Riparian Reserve, Davis, CA . Branches from host northern California black walnut, Juglans hindsii , were paired with branches from six nonhost hardwood species. The landing rate of P . juglandis (412 beetles trapped/8 weeks; 389 on host branches, 23 on nonhost branches) was significantly greater on the host branches for all nonhost hardwoods except Populus fremontii . Proportional comparisons of beetle presence also revealed a significant preference for the host branches compared with all but two nonhost species, Acer negundo and P . fremontii . Capturing P . juglandis without the use of an aggregation pheromone was a rare event, underscoring the difficulty of studying the initial phases of host selection behaviour in bark beetles. Unbaited funnel traps adjacent to selected host trees in the experiment only captured five individuals over a 19‐week period. None were captured in traps adjacent to nonhost trees. This study provided evidence that P . juglandis discriminates between host and nonhost branches while in‐flight. This directed flight behaviour is likely informed by the recognition of both host and nonhost volatile cues. This study established an ecological context for the development of a semiochemical‐based repellent system for protecting walnut trees from future attacks from this invasive bark beetl

The cranberry weevil Anthonomus musculus Say is a key pest of highbush blueberries (Vaccinium corymbosum L.) and cranberries (Vaccinium macrocarpon Aiton) in the northeastern United States. Previous studies have reported A. musculus adult attraction to traps baited with the aggregation pheromone of the pepper weevil Anthonomus eugenii Cano, likely because these two weevils share similar pheromone blends that differ only in two components. The A. musculus aggregation pheromone contains (Z)‐2‐(3,3‐dimethylcyclohexylidene) ethanol (Z grandlure II), (Z)‐(3,3‐dimethylcyclohexylidene) acetaldehyde (grandlure III), (E)‐(3,3‐dimethylcyclohexylidene) acetaldehyde (grandlure IV) and (E)‐3,7‐dimethyl‐2,6‐octadien‐1‐ol (geraniol); whereas A. eugenii produces a pheromone blend that includes (E)‐2‐(3,3‐dimethylcyclohexylidene) ethanol (E grandlure II) and (E)‐3,7‐dimethyl‐2,6‐octadienoic acid (geranic acid) in addition to the four A. musculus pheromone components. Here, we hypothesized that differences in pheromone composition between these two species influence A. musculus adult attraction to its aggregation pheromone. To test this, we studied the response of A. musculus to its pheromone blend with and without E grandlure II and geranic acid, a commercial A. eugenii pheromone lure and a no‐lure control in highbush blueberry and cranberry fields in New Jersey and Massachusetts, respectively. Regardless of crop type, A. musculus adults were more attracted to their four‐component pheromone blend and the blend plus geranic acid than the commercial A. eugenii pheromone and the no‐lure controls. The A. musculus pheromone blend plus E grandlure II and the A. eugenii pheromone blend also captured more A. musculus adults than the no‐lure control but not compared to the commercial A. eugenii pheromone. Further analysis showed that A. musculus adults are significantly (~27%) less attracted to their pheromone blend if it contains E grandlure II, although the addition of geranic acid did not affect their response. These findings may help guide future efforts towards the development of behaviour‐based tools to monitor and manage A. musculus.

The butterfly Heliconius erato occurs in various mimetic morphs. The male clasper scent gland releases an anti-aphrodisiac pheromone and additionally contains a complex mixture of up to 350 components, varying between individuals. In 114 samples of five different mimicry groups and their hybrids 750 different compounds were detected by gas chromatography/mass spectrometry (GC/MS). Many unknown components occurred, which were identified using their mass spectra, gas chromatography/infrared spectroscopy (GC/IR)-analyses, derivatization, and synthesis. Key compounds proved to be various esters of 3-oxohexan-1-ol and (Z)-3-hexen-1-ol with (S)-2,3-dihydrofarnesoic acid, accompanied by a large variety of other esters with longer terpene acids, fatty acids, and various alcohols. In addition, linear terpenes with up to seven uniformly connected isoprene units occur, e. g. farnesylfarnesol. A large number of the compounds have not been reported before from nature. Discriminant analyses of principal components of the gland contents showed that the iridescent mimicry group differs strongly from the other, mostly also separated, mimicry groups. Comparison with data from other species indicated that Heliconius recruits different biosynthetic pathways in a species-specific manner for semiochemical formation.

Background Tephritid fruit flies are recognized as the most economically important insect pest group, causing significant losses to horticultural crops globally. The sterile insect technique (SIT) is used to suppress or eradicate pest fruit flies in many countries. The provisioning of adult dietary or olfactory supplementation pre-release is commonly used to improve the mating performance of sterile male flies in SIT. This study on a major pest species, Queensland fruit fly, Bactrocera tryoni (Froggatt), focused on improving mating performance by providing a semiochemical, raspberry ketone (RK), in the pre-release adult diet. Results Survival was numerically higher for RK-supplemented males. Sexual maturity occurred 1 day earlier (from 7 to 6 days) in RK-supplemented sterile males. The mating latency period decreased with maturation age and was lower for RK-fed males. RK-supplemented sterile males increasingly mated with fertile females as they aged (10-19 days). The mating competitiveness of both RK-supplemented sterile males and RK-denied sterile males was greater than that of wild males. Conclusion The early sexual maturity and increased mating performance of RK-supplemented sterile males indicate that the effectiveness of SIT programmes can be increased through dietary supplementation with RK during the pre-release period. © 2018 Society of Chemical Industry.

Molecular recognition is a fundamental principle in biological systems. The olfactory detection of both food and predators via ecological relevant odorant cues are abilities of eminent evolutionary significance for many species. Pyrazines are such volatile cues, some of which act as both human-centered key food odorants (KFOs) and semiochemicals. A pyrazine-selective odorant receptor has been elusive. Here we screened 2,3,5-trimethylpyrazine, a KFO and semiochemical, and 2,5-dihydro-2,4,5-trimethylthiazoline, an innate fear-associated non-KFO, against 616 human odorant receptor variants, in a cell-based luminescence assay. OR5K1 emerged as sole responding receptor. Tested against a comprehensive collection of 178 KFOs, we newly identified 18 pyrazines and (2R/2S)-4-methoxy-2,5-dimethylfuran-3(2H)-one as agonists. Notably, OR5K1 orthologs in mouse and domesticated species displayed a human-like, potency-ranked activation pattern of pyrazines, suggesting a domestication-led co-evolution of OR5K1 and its orthologs. In summary, OR5K1 is a specialized olfactory receptor across mammals for the detection of pyrazine-based key food odors and semiochemicals.

Whitefly (Hemiptera: Sternorrhyncha: Aleyrodidae) pests, including the tobacco whitefly, Bemisia tabaci, and the greenhouse whitefly, Trialeurodes vaporariorum, are important economically in agriculture. Whiteflies are controlled mainly by synthetic insecticides but resistance to these is evolving rapidly. A semiochemical-based management strategy could provide an alternative to the use of insecticides, by exploiting natural volatile signalling processes to manipulate insect behaviour. Whitefly behaviour is affected by differences in plant odour blends. Selected compounds have been suggested as putative semiochemicals, but in only a few studies have potential volatiles been characterized by electrophysiology or olfactometry. Application of antennal preparation methods from closely related families, the aphids (Hemiptera: Aphididae) and psyllids (Hemiptera: Psyllidae), may help to facilitate whitefly electroantennography. Behavioural bioassays are essential to identify the repellent or attractant effect of each semiochemical. The relevance of semiochemicals in whitefly management needs to be evaluated in the respective cultivation system. Although the value of semiochemicals against whiteflies has not been demonstrated in the field, there is an emerging range of possible field applications and some promising prospects. Overall, the olfactory system of whiteflies needs to be elucidated in more detail. © 2018 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

BACKGROUND Semiochemicals for monitoring, attracting or repelling pest and beneficial organisms are increasingly deployed in agricultural and forest systems for pest management. However, the use of aggregation pheromones and host-plant attractants for the express purpose of increasing the efficacy of classical biological control agents of weeds has not been widely reported. Therefore, we conducted field-based assays to determine if a specialized wax-based matrix impregnated with an aggregation pheromone of the northern tamarisk beetle Diorhabda carinulata (Desbrochers) or host-plant volatiles could increase the efficacy of D. carinulata. RESULTS The aggregation pheromone and host-plant volatiles were formulated for field application using a wax-based matrix. Reported release rates suggest that this matrix is a viable formulation for enhancing D. carinulata aggregations under field conditions. Pheromone-treated saltcedar plants (Tamarix spp.) not only had higher densities of adult and larval D. carinulata, but also sustained greater levels of foliar damage than control plants. Increased damage from the focused feeding of D. carinulata caused an increase in foliar dieback and decrease in live canopy volume of semiochemical-treated plants. CONCLUSION Field deployment of these semiochemical formulations could be useful in directing populations of D. carinulata for increased impact on Tamarix spp. © 2018 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Uncovering the entire process of oviposition could enable the development of innovative pest control strategies. The European grapevine moth Lobesia botrana as well as the European grape berry moth Eupoecilia ambiguella are serious insect pests, which still threaten viticulture in many parts of the world. By creating an artificial semiochemical emitting surface, in form of a card, we tried to develop an egg-monitoring tool for the oviposition of these two species in vineyards. The idea was to create a decision support system that facilitates timing and necessity of insecticide treatments. This article deals exclusively with the initial step towards the development of this tool: the influence of physical factors (colour, shape or texture) of a surface on the oviposition behaviour of L. botrana and E. ambiguella under laboratory conditions. The acceptance of different artificial substrates as oviposition site was analysed exclusive of volatile organic compounds emitted by a host plant. We investigated particular colours of the surface, which could be a visual stimulus to trigger the oviposition of both species. Apparently, the colour green, the texture of the material and the light conditions turned out to be highly important stimuli for oviposition.

The beech leaf-mining weevil, Orchestes fagi L. (Curculionidae: Curculioninae: Rhamphini), a pest of European beech, Fagus sylvatica L. (Fagaceae), was recently discovered infesting American beech, Fagus grandifolia Ehrh., in Nova Scotia, Canada. Adult O. fagi feed on both young and mature leaves of beech as well as on other species (e.g., raspberry, Rubus spp.), but oviposition and larval feeding are restricted to beech. Females oviposit in young developing beech leaves at the time of bud burst. We characterized volatiles emitted from buds, leaves, and sapwood of American beech and examined their potential as attractants alone or when combined with other weevil pheromones for O. fagi. We predicted that adults would be attracted to volatiles emitted from beech leaves, especially those emitted from bursting beech buds. Gas chromatography/mass spectrometry (GC/MS) analyses of volatiles collected from buds at pre- and post-budburst identified two diterpene hydrocarbons, 9-geranyl-p-cymene (1) and 9-geranyl-α-terpinene (2a), that were emitted in large amounts at the time of bud burst. Compound 1 significantly increased mean catch of males and total O. fagi (but not females) on sticky traps compared with unbaited controls. Y-tube bioassays confirmed attraction of male O. fagi to bursting beech buds and compound 1. Attraction of male O. fagi to 1, emitted in large quantities from American beech, is likely adaptive because both oviposition and mating of O. fagi coincide with budburst. Our data suggest that traps baited with 1 may be useful for monitoring the spread of O. fagi in North America.

The leaf beetle Ambrostoma quadriimpressum Motschulsky (Coleoptera: Chrysomelidae) is distributed in China, Siberia, and elsewhere in northeastern Asia. This pest feeds only on buds and leaves of elm trees (Ulmaceae) and inhibits elm trees sprouting, increasing the risk of damage and destruction by other pests. We investigated selected plant compounds that could be used for the development of semiochemical‐based push‐pull methods for the control of this elm pest. Electroantennogram (EAG), Y‐tube olfactometer, and wind tunnel bioassays were conducted to test the electrophysiological and behavioral response of A. quadriimpressum to nine individual volatiles and five essential oils. Individual volatiles and essential oils were selected based on their activity against insects in previous studies. The individual volatiles and essential oils were dissolved in dichloromethane and adsorbed by filter paper. Using a pipette, odor stimuli were delivered as 0.5‐s puffs of air into a continuously humidified air stream in the odor delivery tube at 400 ml per min. Ambrostoma quadriimpressum adults display strong EAG responses to l mol l⁻¹ isoeugenol, (1R)‐(+)‐α‐pinene, 1% pepper oil (derived from the pericarp of Piper chinense Miq.), and peppermint oil [derived from the aerial parts of Mentha haplocalyx (Briq.)] compared to the control. In behavioral assays conducted using a Y‐tube olfactometer and a wind tunnel, adult beetles were attracted by (1R)‐(+)‐α‐pinene but repelled by 0.1% pepper oil. The results provide a basis for the development of a ‘push‐pull’ strategy to manage A. quadriimpressum.

BACKGROUND: \ud Vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), is one of the most economically important pest species of berry and ornamental crops globally. Monitoring this nocturnal pest can be difficult and time consuming and the efficacy of current tools is uncertain. Without effective monitoring tools, implementation of integrated pest management strategies is challenging. This study tests the relative efficacy of a range of vine weevil monitoring tools. Whether host-plant volatiles and weevil feeding experience influence vine weevil capture is also tested. \ud \ud RESULTS: \ud Monitoring tool efficacy differed overall between the six monitoring tool designs tested and ranged from catches of 0.4 % to 26.7 % under semi-field conditions. Previous feeding experience influenced vine weevil behaviour. In yew conditioned populations, 39 % of the weevils responded to and were retained in the trap baited with yew foliage while 37 % of weevils from Euonymus fortunei conditioned populations responded to and were retained in the trap baited with E. forunei foliage. A simple synthetic lure consisting of (Z)-2-pentenol + methyl eugenol also increased vine weevil catches compared with an unbaited trap. \ud \ud CONCLUSION: \ud Demonstrating differences in the efficacy of different monitoring tool designs is an important first step for developing improved methods for monitoring vine weevil populations within crops. This study presents the first direct comparison of vine weevil monitoring tool designs and indicates that trap efficacy can be improved by baiting with host-plant material or a synthetic lure based on host-plant volatiles. This article is protected by copyright. All rights reserved.

Currently, odorant-binding proteins (OBPs) are considered the first filter for olfactory information for insects and constitute an interesting target for pest control. Thus, an OBP (HeleOBP) from the scarab beetle Hylamorpha elegans (Burmeister) was identified, and ligand-binding assays based on fluorescence and in silico approaches were performed, followed by a simulated binding assay. Fluorescence binding assays showed slight binding for most of the ligands tested, including host-plant volatiles. A high binding affinity was obtained for β-ionone, a scarab beetle-related compound. However, the binding of its analogue α-ionone was weaker, although it is still considered good. On the other hand, through a three-dimensional model of HeleOBP constructed by homology, molecular docking was carried out with 29 related ligands to the beetle. Results expressed as free binding energy and fit quality (FQ) indicated strong interactions of sesquiterpenes and terpenoids (α- and β-ionone) with HeleOBP as well as some aromatic compounds. Residues such as His102, Tyr105 and Tyr113 seemed to participate in the interactions previously mentioned. Both in silico scores supported the experimental affinity for the strongest ligands. Therefore, the activity of α-ionone, β-ionone and 2-phenyl acetaldehyde at antennal level was studied using electroantenography (EAG). Results showed that the three ligands are electrophysiologically active. However, an aliquot of β-ionone (represented by 3.0 ng) elicited stronger EAG responses in antennae of males than of females. Finally, the role of these ligands as potential semiochemicals for H. elegans is discussed.

BACKGROUND Agrilus bigutattus (Fabricius) is a forest pest of increasing importance in the United Kingdom. The larvae damage weakened native oaks and are thought to contribute to premature tree death. Suspected links with acute oak decline (AOD) are not yet confirmed, but AOD-predisposed trees appear to become more susceptible to A. biguttatus attack. Thus, management may be necessary for control of this insect. To explore the possibility of monitoring beetle populations by baited traps, the host tree volatiles regulating A. biguttatus–oak interactions were studied. RESULTS Biologically active volatile organic compounds in dynamic headspace extracts of oak foliage and bark were identified initially by coupled gas chromatography–electroantennography (GC-EAG) and GC–mass spectrometry (GC-MS), and the structures were confirmed by GC coinjection with authentic compounds. Of two synthetic blends of these compounds comprising the active leaf volatiles, the simpler one containing three components evoked strongly positive behavioural responses in four-arm olfactometer tests with virgin females and males, although fresh leaf material was more efficient than the blend. The other blend, comprising a five-component mixture made up of bark volatiles, proved to be as behaviourally active for gravid females as bark tissue. CONCLUSIONS These initial results on A. biguttatus chemical ecology reveal aspects of the role of attractive tree volatiles in the host-finding of beetles and underpin the development of semiochemically based surveillance strategies for this forest insect. © 2015 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

BACKGROUND Zoophytophagous predators can trigger plant defenses affecting prey populations beyond predation. Euseius stipulatus is a presumed zoophytophagous phytoseiid common in citrus. The response of citrus to one of its potential prey, Tetranychus urticae, is genotype dependent, with Citrus reshni and C. aurantium exhibiting extreme susceptibility and resistance, respectively. Volatile blends produced upon infestation affected the behavior of these two mites. We wondered whether E. stipulatus could trigger similar responses. RESULTS Euseius stipulatus triggered genotype-dependent defense responses in citrus. Whereas C. aurantium upregulated the Jasmonic Acid, Salicylic Acid and flavonoids defensive pathways, C. reshni upregulated JA only. Likewise, different volatile blends were induced. These blends were exploited by E. stipulatus to select less-defended plants (i.e., those in which higher pest densities are expected) and, interestingly, did not prevent T. urticae from choosing E. stipulatus-infested plants. To the best of our knowledge, this is the first time that this type of response has been described for a zoophytophagous phytoseiid. CONCLUSION The observed responses could affect herbivore populations through plant-mediated effects. Although further research is needed to fully characterize them and include other arthropods in the system, these results open opportunities for more sustainable and effective pest control methods (i.e., combining semiochemicals and biological control). © 2018 Society of Chemical Industry.

Male sexual aggregations are a common territorial, mating-related or resource-based, behaviour observed in diverse organisms, including insects such as thrips. The influence of factors such as plant substrate, time of day, and geographic location on aggregation of thrips is uncertain, therefore we monitored the dispersion of male and female bean flower thrips (BFT), Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), on cowpea, Vigna unguiculata (L.) Walp. (Fabaceae), over three cowpea growth stages and across three cowpea-growing areas of Kenya. Our results indicated that for all the crop growth stages, the density of BFTs varied over the time of day, with higher densities at 10:00, 13:00, and 16:00 hours than at 07:00 hours. Thrips densities did not differ among blocks at the budding stage, but they did at peak flowering and podding stages. Dispersion indices suggested that both male and female BFTs were aggregated. Active male aggregation occurred only on green plant parts and it varied across blocks, crop stages, and locations. Similarly, active female aggregation was observed in peak flowering and podding stages. Such active aggregation indicates a semiochemical or behaviour-mediated aggregation. Identification of such a semiochemical may offer new opportunities for refining monitoring and management strategies for BFT on cowpea, the most important grain legume in sub-Saharan Africa.

Numerous semiochemicals have been isolated from several species of astigmatid mites with various identified or unidentified functions. Alarm pheromonal activity is widespread with neryl formate and neral, being the most common compounds eliciting alarm response in conspecifics. The cosmopolitan astigmatid mite Suidasia medanensis (= S. pontifica) Oudemans (Acari: Suidasidae) has been reported to use neral as an alarm pheromone, but neral can also act as an allomone towards predators of oribatid mites. Suidasia medanensis can be utilised as a factitious prey for mass-rearing of the phytoseiid predatory mite Amblyseius (= Typhlodromips) swirskii (Athias-Henriot) (Acari: Phytoseiidae), which is used for biological control of insect and mite pests in protected crops. This study investigated the potential defence properties of the S. medanensis volatiles against A. swirskii, comparing the repellency to pollen-reared (naive) vs. S. medanensis-reared (experienced) predators using a synthetic blend of the isomers neral and geranial (1:1) as a model compound. In a repellency bioassay, the synthetic blend elicited a significant repellence to A. swirskii with no difference between naive and experienced predators. During capture success studies, S. medanensis under repeated attack could release sufficient quantities of the defence volatile to deter 1–5 attacks from A. swirskii, whereas hexane-treated S. medanensis artificially depleted of volatiles were significantly more vulnerable to an attack. This is the first report of an astigmatid defence volatile with repellent activity to a phytoseiid mite and the starting point to understanding semiochemical interactions in any current or novel factitious predator-prey mass-rearing system.

The burnet moth Zygaena filipendulae L. contains the cyanogenic glucosides linamarin and lotaustralin, which can be degraded to the volatiles hydrogen cyanide (HCN), acetone and 2-butanone. Linamarin and lotaustralin are transferred from the male to female during mating and thus are considered to be involved in mating communication. Because volatile semiochemical cues play a major role in mating communication in many insect species, the emissions of HCN, acetone and 2-butanone from Z. filipendulae are characterized in the present study, aiming to determine the interplay between the degradation products of cyanogenic glucosides and pheromones. The volatile emissions from Z. filipendulae and flowers inducing mating are measured using headspace solid-phase micro-extraction and gas chromatography-mass spectrometry analysis. All Z. filipendulae life stages emit HCN, acetone and 2-butanone. Virgin females show higher emissions than mated females, whereas mated males have higher emissions than virgin males. Hydrogen cyanide is only rarely detected in the course of male–female copulation. These observations indicate a role for the cyanogenic glucoside derived volatiles in female calling and male courtship behaviours, although not as a defence during copulation. Males rejected for mating by a female are accepted after injection of linamarin or lotaustralin, demonstrating that cyanogenic glucosides are also important for female assessment of the fitness of the male. Volatiles from flowers occupied during mate calling are also analyzed, and emissions from males and females result in the identification of novel putative pheromones for Z. filipendulae.

Electroantennogram (EAG), Y-tube olfactometer, and wind tunnel bioassays were conducted to test the electrophysiological and behavioral responses of Cryptorrhynchus lapathi L. (Coleoptera: Curculionidae) to six individual volatiles and seven essential oils (compounded volatiles). The aim of this study was to select effective plant compounds that can be used in the development of semiochemical-based push–pull methods for the control of this harmful insect. Male and female C. lapathi displayed strong EAG responses to linoleic acid, α-pinene, (Z)-3-hexen-1-ol, geraniol, turpentine oil, and salicylaldehyde. Y-tube olfactometer assays indicated that salicylaldehyde and α-pinene elicited strong repellent effects on female C. lapathi. Linoleic acid and (Z)-3-hexen-1-ol showed greater luring effects on male and female C. lapathi compared with the control. Turpentine oil was stronger repellent, and geraniol showed stronger luring effects on male C. lapathi than the control. Wind tunnel assays with both male and female C. lapathi indicated that salicylaldehyde, α-pinene, and turpentine oil elicited repellent effects compared with the control. Linoleic acid, (Z)-3-hexen-1-ol, and geraniol were stronger lures of both male and female C. lapathi than the control. These results provide a basis for the further development of C. lapathi luring and repellent agents.

Pyrazines are well-known natural products that are present in bacterial odours and food flavouring agents and are used as insect pheromones. Recently, a number of hydroxymethylpyrazines have been identified as thynnine wasp pheromones and orchid semiochemicals that are essential for pollination in sexually deceptive plants. These compounds are present in low amounts in complex blends, making GC-MS (including high-resolution techniques) the method of choice for their structure elucidation. We report the EI mass spectra for 14 representative compounds and have found that based on characteristic fragmentations, it is possible to distinguish between different positional isomers of hydroxymethylpyrazines. The presence or absence of either [M - 17]+ , [M - 18]+· or [M - 19]+ fragment species provides characteristic information to allow the distinction between the different isomers. Considering the importance of pyrazines as a group of bioactive natural products, and the recent findings of biological activity for hydroxymethylpyrazines, our results presented here will aid the identification of these compounds in other biological systems. Copyright © 2015 John Wiley & Sons, Ltd.

The attraction of wild tephritids to semiochemical-based lures is the ideal basis for trap network design in detection programmes, but in practice, mass-reared colony insects are usually used to determine trap efficiency. For Bactrocera cucurbitae Coquillett, a lower response by wild males compared with colony-derived individuals, usually used to estimate attraction parameters, could mean that the sensitivity of detection networks targeting this pest is reduced. We describe the results of mark–release–recapture experiments with wild- and colony-derived B. cucurbitae males in a grid of cuelure-baited traps within a macadamia nut orchard in Hawaii Island designed to quantify the attraction of cuelure to each fly type. For colony males, we estimate a 65% probability of capture at 27 m, intermediate with previous estimates on the attraction of methyl eugenol to Bactrocera dorsalis Hendel (36 m) and trimedlure to Ceratitis capitata Wiedemann (14 m) at the same site. Results suggest similar response over distance by wild-derived B. cucurbitae compared with colony in the field, but there may be qualitative differences in response between wild and colony based on very low response of wild males in a standard bioassay of attraction. For both fly types, the estimates of attraction in the smaller of two grid sizes tested were lower than for the larger spacing, suggesting trap competition was a factor at an intertrap distance of 75 m. Dispersal patterns within the grid were generally to the south for the colony-derived males and more variable for the wild-derived males. In neither case was the direction of recapture correlated with the prevailing direction of the wind.

Many natural enemies employ plant- and/or herbivore-derived signals for host/prey location. The larval parasitoid Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) is 1 of 3 biocontrol agents currently being released in an effort to control the emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coloeptera: Burprestidae) in North America. To enhance its efficiency, allelochemicals that attract it need to be assessed. In this study, ash phloem volatile organic compounds (VOCs) of black, green, and white ash, and EAB larval frass were compared. Foraging behavior of T. planipennisi females in response to VOCs of white ash or frass from EAB larvae feeding on white ash phloem was tested using a Y-tube olfactometer. Results indicated that the 3 ash species had similar VOC profiles. EAB larval frass generally contained greater levels of VOCs than phloem. Factor analysis indicated that the 11 VOCs could be broadly divided into 2 groups, with α-bisabolol, β-caryophyllene, (E)-2-hexenal, (Z)-3-hexenal, limonene, methyl benzoate, methyl indole-3-acetic acid, methyl jasmonate, methyl salicylate as the first group and the rest (i.e., methyl linoleate and methyl linolenate) as a second. Abundance of VOCs in white ash phloem tissue and frass, nevertheless, did not attract T. planipennisi females. The concealed feeding of EAB larvae might explain the selection for detectable and reliable virbrational signals, instead of undetectable and relatively unreliable VOC cues from phloem and frass, in short-range foraging by T. planipennisi. Alternatively, it is possible that T. planipennisi is not amenable to the Y-tube olfactometer assay employed.

BACKGROUND Populations of red palm weevil (RPW), a severe pest of palms in Mediterranean countries, might be limited by semiochemical-based behaviour-disrupting methods. We evaluated the effects of electroantennogram (EAG)-active plant volatiles on the behaviour of RPWs from Italy and Israel. In field experiments, α-pinene, citronellol, geraniol, citral and 1-octen-3-ol were tested for their ability to disrupt attraction to pheromone–kairomone and molasses baited traps. Those that were found to be disruptive in the field were evaluated in a laboratory choice bioassay in individual cages for their effect on RPW female feeding and oviposition. RESULTS Field experiments showed reduced captures in traps loaded with geraniol (−57%), 1-octen-3-ol (−50%) or α-pinene (−45% to −60%); captures in citronellol- or citral-loaded traps did not differ from control. In laboratory experiments, 1-octen-3-ol was the most potent behaviour-modifying compound, eliciting a significant/marginally significant reduction in both feeding and oviposition at the lowest dose tested in both populations. Geraniol generally caused a strong reduction in feeding and oviposition at each dose tested (Israel), or at the highest dose (Italy). α-Pinene caused some reduction in feeding activity at the highest dose tested (Italy), but no consistent repellency (Israel). CONCLUSION Field and laboratory data suggest the potential for the use of 1-octen-3-ol, geraniol and α-pinene for RPW population management. © 2014 Society of Chemical Industry

The Australian cotton industry is now dominated by transgenic (Bt) varieties, which provide a strong platform for integrated pest management (IPM) of Helicoverpa spp. (Lepidoptera: Noctuidae). New IPM-compatible tools are required to manage the development of resistance in Helicoverpa spp. and the control of other sucking pests. A 10-year study commenced in 2001 to identify short-range, non-volatile compounds on organ surfaces of plants that deter feeding or oviposition, or are toxic and do not support development of Helicoverpa spp. on cotton plants. The results of the initial study identified Clitoria ternateaL. (Fabaceae) as non-preferred for Helicoverpa spp. oviposition and larval feeding. The study found that C. ternatea fractionalized extract mixture (fractions 2, 3, 4, and 6) caused oviposition and feeding deterrence as well as direct toxicity to Helicoverpa spp. This study has developed an oil-based semiochemical product from C. ternatea identified in the initial study into a potential commercial product. The application of 1–2% (vol/vol) of the oil-based formulation of the C. ternatea mixture against Helicoverpa spp. on commercial transgenic and conventional cotton crops resulted in Helicoverpa spp. oviposition and larval feeding deterrence, as well as caused direct mortality to larvae. No negative effect on beneficial insects was observed. In conclusion, the ability of the oil-based C. ternatea mixture to control Helicoverpa spp. infestations, while conserving beneficial insect populations, suggests its potential for use in supplementing IPM programs to reduce the use of synthetic insecticides on transgenic and conventional cotton crops.

BACKGROUND The identification of new attractants can present opportunities for developing mass trapping, but standard screening methods are needed to expedite this. We have developed a simple approach based on quantifying trap interference in 4 × 4 trap arrays with different spacings. We discuss results from sex pheromones in Lepidoptera (light brown apple moth, Epiphyas postvittana), Diptera (apple leaf curling midge, Dasineura mali) and Homoptera (citrophilous mealybug, Pseudococcus calceolariae), compared with a kairomone for New Zealand flower thrips (Thrips obscuratus). RESULTS The ratio of catch in corner traps to catch in centre traps was 25:1 at 750 D. mali traps ha−1, and was still ∼5:1 at 16 traps ha−1, suggesting trap interference even at such low trap densities. Trap competition for sex pheromone lures at close spacing (

The polyphagous navel orangeworm, Amyelois transitella Walker (Lepidoptera: Pyralidae), is a major insect pest of almonds and pistachios in California (USA). Amyelois transitella moths have proven difficult to monitor and control for over 5 decades; however, recent reports indicate progress towards attractants using pheromone or semiochemical blends. Despite advances of a host plant volatile attractant blend that is effective for monitoring moth populations in almond orchards, the blend’s attractancy and capture efficacy of A. transitella has not translated to pistachio orchards. The apparent orchard specificity of A. transitella to the blend suggests a different composition of host plant volatiles is needed to either improve the current blend or a new blend formulation is required for monitoring in pistachio orchards. One objective of this study was to evaluate available individual host volatiles via a standardised puff method in combination with electroantennographic analysis. In total 105 volatiles were evaluated individually for their ability to elicit an electrophysiological chemoreception response from excised male and female A. transitella antennae. Male antennae responded significantly higher to alcohols, aldehydes, alkyls, aromatics, and ketones. Female antennae responded significantly higher to benzenoids, monoterpenes, sesquiterpenes, and short-chain alcohols.

When female blow flies Lucilia sericata and Phormia regina (Diptera: Calliphoridae) oviposit in aggregations on carrion, even-aged larval offspring reportedly develop faster, and fewer are parasitized or preyed upon. The benefits of aggregated oviposition equally affect con- and heterospecific larvae sharing a resource. The benefits imply that female blow flies engage in coordinated, pheromone-mediated oviposition behavior. Yet, repeated attempts to identify oviposition pheromones have failed invoking doubt that they exist. Simply by regurgitating and feeding on carrion, flies may produce attractive semiochemicals. If flies were to aggregate in response to feeding flies rather than ovipositing flies, then the semiochemical cue(s) may be associated with the salivary gland. Working with L. sericata and P. regina and using liver as a surrogate oviposition medium, we test the hypotheses, and present data in their support, that (i) gravid or nongravid females ovipositing and/or feeding on liver enhance its attractiveness to gravid and nongravid females; (ii) females respond to semiochemicals from feeding heterospecific females; (iii) females respond equally well to semiochemicals from feeding con- and heterospecific females; (iv) macerated head tissues of females applied to liver enhance its attractiveness; and (v) females in direct contact with and feeding on liver, but not when next to yet physically separated from liver, enhance attraction of flies. We conclude that oviposition site-seeking females do not respond to an oviposition pheromone. Instead, they appear to coopt semiochemicals associated with feeding flies as resource indicators, taking chances that resources are suitable for oviposition, and that ovipositing flies are present.

Insect hydrocarbons (HCs) primarily serve as a waterproofing cuticular layer and function extensively in chemical communication by facilitating species, sex, and colony recognition. In this study, headspace solid-phase microextraction is employed for investigating the sex-specific volatile HC profile of five ladybirds collected from Lucknow, India namely, Coccinella septempunctata (L.), Coccinella transversalis (Fabr.), Menochilus sexmaculatus (Fabr.), Propylea dissecta (Mulsant), and Anegleis cardoni (Weise) for the first time. Major compounds reported in C. septempunctata, C. transversalis, and A. cardoni are methyl-branched saturated HCs, whereas in M. sexmaculatus, and P. dissecta, they are unsaturated HCs. Other than A. cardoni, both the sexes of the other four ladybirds had similar compounds at highest peak but with statistically significant differences. However, in A. cardoni, which is a beetle with a narrow niche, the major compound in both male and female was different. The difference in volatile HC profile of the sexes of the five ladybirds indicates that gender-specific differences primarily exist due to quantitative differences in chemicals with only very few chemicals being unique to a gender. This variation in semiochemicals might have a role in behavioral or ecological aspects of the studied ladybirds.

We compared standard multiple-funnel, modified multiple-funnel, intercept panel and canopy malaise (SLAM) traps with top and bottom collecting cups for their effectiveness (species richness, rarity, abundance) at capturing Cerambycidae in eastern North America. 2 Experiments were conducted in New York, Louisiana, Massachusetts and Georgia in 2011 and 2012. A combination of pheromones and host volatiles chosen to match local forest types were used as lures. 3 Species richness tended to be higher in SLAM and modified funnel traps than standard funnel and intercept panel traps. SLAM traps also captured the highest number of species, unique species, rare (species accounting for ≤ 1% of total cerambycids at a site) and singleton species at each site. 4 Individual-based rarefaction and sample-based species accumulation curves suggested that SLAM traps are more effective for capturing cerambycid species. For many estimates, modified funnel and funnel traps were lower than SLAM traps but greater than intercept panel traps for describing cerambycid communities. 5 Modified funnel and SLAM traps generally captured the highest abundance of cerambycids but the response of the individual subfamily and species varied by trap type. 6 SLAM traps should be considered as a strong tool to describe cerambycid communities when used in conjunction with pheromones and host volatiles.

The Australian cotton production system is dominated by transgenic Bt (Bollgard II®) cotton varieties, Gossypium hirsutum L. (Malvaceae). These provide good control of lepidopteran pests (Helicoverpa spp.; Noctuidae) but are not effective against sucking pests. Recent trends in the frequency of resistance alleles in Helicoverpa spp. indicate the threat of pest resistance. Therefore, new technologies are required to manage the development of resistance and the resurgence of sucking pests. Consequently, the study was aimed to develop a semiochemical product able to deter feeding and oviposition of Helicoverpa spp., as well as cause direct mortality to the pest on transgenic and non-transgenic crops. Plants including sorghum, sweet corn, pigeon pea, and lucerne (used as refuge crops in cotton), various cotton genotypes (MHR11, Lumein, and Sicala VII), and the native plant Clitoria ternatea L. (Fabaceae) were cultivated within cotton crops and in cages, and assessed for the occurrence of oviposition by Helicoverpa spp. and survival of the pest larvae. The results indicated that pigeon pea, cotton, sorghum, and sweet corn were most preferred for Helicoverpa spp. oviposition and feeding, whereas C. ternatea was least preferred. We used a solid phase extraction technique to obtain six fractions of an extract of C. ternatea, which we assessed for bioactivity against Helicoverpa spp. We found that fractions 2, 3, 4, and 6 had oviposition and feeding deterrence as well as direct toxicity to Helicoverpa spp. Clitoria ternatea fractions 2, 3, 4, and 6 have been developed into a product (Sero-X®) that is effective against Helicoverpa spp. and sucking pests, and is in an advanced stage of commercialisation.

The five-spined bark beetle, Ips grandicollis, is an exotic pest in Australia that preferentially attacks stressed pine trees, including Pinus radiata D. Don, but it can also attack healthy trees. The beetle has been present in Australia for 70 years, feeding principally on logging debris, with occasional outbreaks resulting in damage to plantations. Attack on trees stressed by drought, fire or storm damage leads to occasional significant losses. In recent years, I. grandicollis has been observed to attack 'trap trees' treated with herbicide to make them attractive to Sirex noctilio Fabricius as part of a successful biological control programme against this wood wasp. Ips grandicollis is able to tolerate a wide range of climatic conditions, and has an extensive geographical range (limited by host tree plantings). The economic impact of I. grandicollis is exacerbated by adults vectoring a fungus, Ophiostoma ips (Rumbold) Nannfeldt, which discolours the outer sapwood and contributes to tree death. Nematodes also are also associated with I. grandicollis, both in the body cavity and under the elytra. The dominant nematode is Contortylenchus grandicolli Massey, which is found internally, in haemocoel, the gut and the head region of the majority of adult beetles. Mites and bacteria are also associated with I. grandicollis but their biology is not well known. Since the first detection of I. grandicollis in Australia, various bio-control and other management strategies have been tested. While a better understanding of the microbial and nematode associates of I. grandicollis may yield novel approaches for the management of this exotic pest, semiochemical-based disruptants offer more immediate scope, particularly for protecting small areas of high value trees such as trap tree plots.

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stal), native to Northeastern Asia, is a serious invasive pest in the United States, Canada, Switzerland, Germany and France. Several common essential oils and their compositions were tested against BMSBs as potential repellents. All the tested individual essential oils and a ternary oil blend showed sig- nificant repellency to both BMSB nymphs and adults. Clove oil, lemon- grass oil, spearmint oil, ylang-ylang oil, and the ternary oil mixture (clove, lemongrass and spearmint) almost completely blocked attraction of BMSBs to the stink bug attractant-baited traps; whereas wintergreen oil, geranium oil, pennyroyal oil and rosemary oil resulted in 60-85% trap catch reductions. Over 20 BMSB antennally active compounds were iden- tified from SPME headspace samples of the eight repellent essential oils using GC-EAD and GC-MS techniques. Among the synthetic EAD-active compounds tested in the field, eugenol, l-carvone, p/l-menthone, pule- gone, methyl salicylate, trans/cis-citral, methyl benzoate and b-caryophyl- lene significantly reduced trap catches of BMSBs by 72-99%; these compounds are likely responsible for the repellency of their corresponding essential oils. Surprisingly, a synthetic mixture of the predacious spined soldier bug (SSB) (Podisus maculiventris (Say)) aggregation pheromone (trans-2-hexenal, a-terpineol and benzyl alcohol) also showed a signifi- cant inhibition of BMSB response to its attractants. These repellent essen- tial oils and their active compounds, as well as the synthetic SSB pheromone, are potentially useful as part of an efficient, environmentally sound semiochemical-based IPM programme to combat this serious inva- sive stink bug.

Trapping approaches developed for the emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), were adapted for trapping several European oak buprestid species. These approaches included the use of natural leaf surfaces as well as green and purple plastic in sticky trap designs. Plastic surfaces were incorporated into novel ‘branch-trap’ designs that each presented two 5 9 9-cm 2 rectangular surfaces ona cardboardstructure wrapped aroundthe leavesofa branch. We used visual adult Agrilus decoys in an attempt to evoke male mating approaches toward the traps. Our first experiment compared the attractiveness of visual characteristics of the surfaces of branchtraps. The second looked at the effect on trap captures of adding semiochemical lures, including manuka oil, (Z)-3-hexen-1-ol, and (Z)-9-tricosene. In total, 1 962 buprestid specimens including 14 species from the genus Agrilus were caught on 178 traps in a 22-day time-span. Overall, the green plastic-covered branch-traps significantly out-performed the other trap designs. We further found that the presence of an EAB visual decoy placed on the trap surface often increased captures on these green traps, but this effect was stronger for certain Agrilus species than for others. The visual decoy was particularly important for the most serious pest detected, Agrilus biguttatus Fabricius, which was captured 13 times on traps with decoys, but only once without a decoy. There were some small but significant effects of odor treatment on the capture of buprestids of two common species, Agrilus angustulusIlliger andAgrilus sulcicollisLacordaire. There were also 141 Elateridae specimensonthese traps, which were not influenced by trap type or decoys. The results suggest that small branch-traps ofthis nature can provide a useful newtoolfor monitoring ofbuprestids, which have the potential to befurtheroptimizedwithrespect to visualandolfactorycues.

Synanthedon myopaeformis Borkhausen (Lepidoptera: Sesiidae) is a diurnal clearwing moth native to Eurasia that was recently introduced into British Columbia (BC) and Ontario, Canada, where it has become a serious pest in apple orchards. In BC, these moths commonly feed on nectar of inflorescences, particularly that of showy milkweed, Asclepias speciosa Torrey (Apocynaceae). We investigated the relative importance of visual and olfactory cues, and the key floral semiochemical(s) mediating attraction of S. myopaeformis to A. speciosa. In field experiments, inflorescences left exposed or enclosed in cheesecloth bags dyed green induced similar visitation rates by moths, indicating that olfactory cues are attractive. Among the >10 floral odourants that elicited responses from moth antennae in coupled gas chromatographic-electroantennographic detection analyses, phenylacetaldehyde induced the most frequent proboscis extension reflexes of male and female moths. Among eight floral odourants that were field-tested singly, phenylacetaldehyde attracted 35 times more male and female moths than any other candidate semiochemical. Attractiveness of phenylacetaldehyde could not be enhanced by admixture with other floral odourants at the ratios or concentrations tested indicating that it alone may mediate attraction of S. myopaeformis to the inflorescences of A. speciosa. The potential use of phenylacetaldehyde as bait to monitor or mass-trap populations of male and female S. myopaeformis should be investigated.

The spruce bark beetle, Ips typographus, is a recent new introduction to the Qilian Mountains of China. An outbreak of these beetles has infested over 0.03 million hectares of spruce forests in this area. Although primary attraction to volatiles has been clearly demonstrated for I. typographus, the existence and role of attraction to insect-produced pheromones have been widely debated. Currently, commercial lures for I. typographus include only the volatiles ipsdienol, cis-verbenol, trans-verbenol, 2-methyl-3-buten-2-ol and 2-phenylethanol in Europe. Several potential pheromone candidates have been identified for I. typographus. Our GC–MS and GC–FID analyses volatiles from hindgut extracts of I. typographus in different attack phases demonstrated that the 2-methyl-3-buten-2-ol, ipsdienol, cis-verbenol and trans-verbenol as major hindgut components, and ipsenol, 2-phenylethanol, trans- myrtenol and verbenone as minor components. We tested various combinations of semiochemical candidates, to determine an optimal blend. Our results suggest that addition of 2-methyl-3-buten-2-ol to either ipsenol alone, or to blends of ipsenol and other semiochemical candidates, significantly enhanced attraction of I. typographus. Therefore, a simple lure consisting of ipsenol and 2-methyl-3-buten-2-ol would be an optimal blend of I. typographus in the Qilian Mountains, China. We conclude that this optimal semiochemical blend may provide an effective biological pest control method for use in forest ecosystem against I. typographus.