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ABSTRACT The tri‐trophic interactions among five cabbage (Brassica oleracea var. capitata) cultivars—Copenhagen Market (CM), Red Acre (RA), Vertus Savoy (VS), Sugarloaf (SL) and Danish Ballhead (DBH)—a generalist aphid, Myzus persicae (Sulzer) and its parasitoid, Diaeretiella rapae McIntosh, were assessed. Copenhagen Market, known for its reported aphid resistance, recorded the fewest aphids (9.11 per plant; F = 6.50; df = 4, p < 0.01), followed closely by Red Acre (11.83 per plant), which was statistically similar. Upon aphid attack, all cultivars produced plant volatiles that influenced the attraction of the parasitoid, D. rapae. Copenhagen Market consistently showed a higher response across cultivar combinations, attracting 62.59%–67.50% of parasitoids. It also recorded a higher parasitisation rate (39.9%; F = 5.94; df = 4/20, p < 0.01) in a multiple‐choice test. The results indicate that cabbage cultivars employ both constitutive and induced resistance, as aphid‐resistant cultivars were also found to be more attractive to parasitoids. In addition to plant odour cues, factors such as plant colour, texture and host aphid kairomones can influence the orientation and parasitisation by D. rapae. [ABSTRACT FROM AUTHOR]

Canine olfaction is a highly developed sense and is utilized for the benefit of detection applications, ranging from medical diagnostics to homeland security and defense prevention strategies. Instrumental validation of odor delivery methods is key to standardize canine olfaction research to establish baseline data for explosive detection applications. Solid-phase microextraction gas chromatography (SPME/GC-MS) was used to validate the odor delivery of an olfactometer. Three explosive classes were used in this study: composition C-4 (C-4), trinitrotoluene (TNT), and ammonium nitrate (AN). Dynamic airflow sampling yielded the successful detection of previously reported target volatile organic compounds (VOCs): 2,3-dimethyl-2,3-dinitrobutane (DMNB) in C-4 and 2-ethylhexan-1-ol (2E1H) in ammonium nitrate and TNT across odor dilutions of 80%, 50%, 25%, 12%, and 3%. C-4 highlighted the most reliable detection from the olfactometer device, depicting a response decrease as a function of dilution factor of its key odor volatile DMNB across the entire range tested. TNT only portrayed 2-ethylhexan-1-ol as a detected odor volatile with a detection response as a function of dilution from 80% down to 12%. Comparatively, ammonium nitrate also depicted 2-ethylhexan-1-ol as an odor volatile in the dynamic airflow sampling but with detection only within the upper scale of the dilution range (80% and 50%). The results suggest the importance of monitoring odor delivery across different dilution ranges to provide quality control for explosive odor detection using dynamic airflow systems. [ABSTRACT FROM AUTHOR]

The blister beetle Epicauta atomaria (Germar) (Coleoptera: Meloidae) is a phytophagous pest of various agricultural crops, especially in Amaranthaceae, Solanaceae, and Fabaceae. Currently, this insect is managed through the spraying of synthetic insecticides that cause serious human health and environmental damage. To reduce the use of synthetic insecticides, the integrated pest management (IPM) programs for other crop pests rely on the use of semiochemical compounds, such as pheromones, kairomones, and allomones, to manipulate the insects' behavior to prevent crop damage. However, studies on semiochemical compounds related to E. atomaria have never been carried out. For this reason, the aim of this study was to explore the chemical communication of E. atomaria. This includes the existence of (i) a sex and/or an aggregation pheromone, (ii) attractant volatile kairomones from host plants, and (iii) repellent volatile allomones from non‐host plants. Tests were carried out using olfactometers and an experimental arena. First, olfactometer tests failed to show the existence of volatile sex and/or aggregation pheromones of these insects. Second, olfactometer and experimental arena tests failed to demonstrate attraction of E. atomaria via volatile kairomonal compounds from host plants (chard, bell pepper, and cock's‐eggs). However, olfactometer tests showed that non‐host plants of E. atomaria (thyme and lavender) emit allomonal volatile compounds with repellent activity. This work represents a first step toward the elucidation of the chemical ecology of E. atomaria and suggests that volatiles from non‐host plants help shape the host preferences of these insects. Those volatiles could be used as a "push" component in a "push–pull" strategy against this pest. [ABSTRACT FROM AUTHOR]

Canine olfaction is a highly developed sense and is utilized for the benefit of detection applications, ranging from medical diagnostics to homeland security and defense prevention strategies. Instrumental validation of odor delivery methods is key to standardize canine olfaction research to establish baseline data for explosive detection applications. Solid-phase microextraction gas chromatography (SPME/GC-MS) was used to validate the odor delivery of an olfactometer. Three explosive classes were used in this study: composition C-4 (C-4), trinitrotoluene (TNT), and ammonium nitrate (AN). Dynamic airflow sampling yielded the successful detection of previously reported target volatile organic compounds (VOCs): 2,3-dimethyl-2,3-dinitrobutane (DMNB) in C-4 and 2-ethylhexan-1-ol (2E1H) in ammonium nitrate and TNT across odor dilutions of 80%, 50%, 25%, 12%, and 3%. C-4 highlighted the most reliable detection from the olfactometer device, depicting a response decrease as a function of dilution factor of its key odor volatile DMNB across the entire range tested. TNT only portrayed 2-ethylhexan-1-ol as a detected odor volatile with a detection response as a function of dilution from 80% down to 12%. Comparatively, ammonium nitrate also depicted 2-ethylhexan-1-ol as an odor volatile in the dynamic airflow sampling but with detection only within the upper scale of the dilution range (80% and 50%). The results suggest the importance of monitoring odor delivery across different dilution ranges to provide quality control for explosive odor detection using dynamic airflow systems.

Aphidius platensis Brèthes (Hymenoptera: Braconidae) is a parasitoid of cereal aphids. Its foraging, recognition, and host acceptance processes may be related to chemical cues inherited from the host during development. This study aimed to evaluate the influence of the maternal host, that is, Rhopalosiphum padi (L.) (Rp), Schizaphis graminum (Rondani) (Sg) (from the Aphidini tribe), Metopolophium dirhodum Walker (Md), and Sitobion avenae (Fabricius) (Hemiptera: Aphididae) (from the Macrosiphini tribe) (all Hemiptera: Aphididae) on parasitism and chemotactic responses of A. platensis. Parasitism by A. platensis was investigated in non‐choice bioassays along four generations, as well as in choice bioassays. Females originating from a S. graminum laboratory colony (SgLab) were reared for four generations on all four aphid species. Chemotaxis experiments were conducted in a four‐armed olfactometer with two A. platensis strains: one originated from SgLab and another after three generations on Rp (RpF4), both exposed to the four aphid species simultaneously. The highest SgLab A. platensis parasitism rates, in both choice and non‐choice tests, were observed on S. graminum, followed by R. padi and S. avenae. No parasitized hosts were found in M. dirhodum. Furthermore, SgLab A. platensis exhibited a stronger attraction to the odors emitted by S. graminum. However, after the third generation on R. padi (RpF4), A. platensis behavior altered, displaying a preference for R. padi over S. graminum, both in terms of parasitism and chemotactic responses. In conclusion, A. platensis showed a preference for hosts within the Aphidini tribe, indicating innate affinities. Nevertheless, its preference can be modified within this tribe based on the chemical cues inherited from the host during development. [ABSTRACT FROM AUTHOR]

Plant herbivore interactions have long been recognized as a complex interplay influenced by various factors, including plant volatile emissions. Understanding the role of these volatiles in mediating plant predator interactions is crucial for developing sustainable pest management strategies. This study investigated the olfactory preferences of Chrysoperla externa larvae for volatiles emitted by Eucalyptus urograndis leaves, focusing on both seedlings and essential oils (EOs). We used Y-tube olfactometry to compare larval preferences between the clean air and various plant treatments, including undamaged and herbivore-damaged leaves. Chemical analysis of EOs revealed higher concentrations of oxygenated monoterpenes and sesquiterpenes in young and damaged leaves, particularly linalool, which has been implicated in insect attraction. Our results showed a significant preference for volatiles emitted by young damaged leaves over clean air for both seedlings (χ2 = 11.03, p = 0.001) and EOs (χ2 = 9.76, p = 0.002). Chrysoperla externa larvae are significantly attracted to specific volatiles from damaged E. urograndis leaves, suggesting these compounds could serve as cues for natural enemy foraging. Our findings enhance the understanding of plant–predator dynamics and suggest potential applications of eucalyptus plantations to sustain C. externa populations for biocontrol purposes. [ABSTRACT FROM AUTHOR]

Recent developments in insect science and technology and integrated pest management (IPM) are laying a concrete path for transition from the dreaded chemical-based pest management to biological and biorational-based methods. Herbivore-induced plant volatiles (HIPVs) play an important role in host plant–herbivore–natural enemy interactions and have the potential to enhance the effectiveness of biological and biorational-based controls for integrated pest management (IPM). Synthetic HIPV blends can potentially improve the foraging behavior of predators by attracting them. This study was conducted to explore the emission of plant volatiles under infestation by cotton aphids, Aphis gossypii Glover, and their influence on attraction response of predatory six-spotted ladybird beetle, Cheilomenes sexmaculata (Fab.). Cotton leaf extracts were analyzed by gas chromatography coupled mass spectrometry (GC–MS), and the response of C. sexmaculata to the various extracts was assessed with a Y-tube olfactometer. By comparing the volatile profile of aphid-infested leaf extract with that of uninfested leaf extract, three compounds, namely 3-carene, pentadecane, and α-linolenic acid, were identified as aphid-induced HIPVs. However, the abundance of the other three compounds, heptane, 3-hexenal, and α-copaene significantly increased upon aphid infestation. At a concentration of 5%, aphid-infested leaf extract had the greatest effect on both female (85.9 ± 7.6%) and male (80.9 ± 6.4%) beetles. These results confirmed that HIPVs induced by aphids in cotton could attract C. sexmaculata beetles. Future tests need to be conducted to determine which compounds could be exploited as attractants for C. sexmaculata. [ABSTRACT FROM AUTHOR]

BACKGROUND: The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a significant threat to crop production. Alternatives to synthetic pesticides are needed for its management. Here we investigated the effect of sulphur on H. halys. Experiments were performed to evaluate both mortality and deterrence/repellence of H. halys following sulphur treatments in laboratory and semi‐field conditions. RESULTS: Brown marmorated stink bug mortality was not influenced by sulphur applications. However, in two‐choice experiments in insect cages and olfactometer, more H. halys adults moved toward the untreated control rather than the sulphur‐treated food sources, with a high effect as the concentration increased. A semi‐field experiment using potted apple plants confirmed the results observed in the laboratory, showing a deterrent and/or repellent effect of sulphur‐based products on H. halys. CONCLUSIONS: Sulphur applications were associated with a deterrent/repellent effect on the brown marmorated stink bug. The use of sulphur‐based products could represent a promising tool for Integrated Pest Management strategies against H. halys in fruit crops. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Dung odours are composed of a large number of different volatile organic compounds (VOCs). Dung beetles are attracted to dung by olfactory cues, and their selection depends on the odorous VOCs emitted from this resource. The possible effects of ivermectin (IVM) on the chemical composition of dung volatile emissions and how this could modify its attraction to dung beetles have been debated for years.In this work, we analysed the possible effects of IVM on the VOCs emitted by cattle dung and the attraction of the dung beetle Ateuchetus cicatricosus Lucas, using behavioural bioassays.The results of the study showed that the chemical analyses of the dung volatile emissions from untreated cattle, treated cattle with IVM (200 μg/kg b.w.; collected at 7 and 14 days post‐administration) and dung spiked with IVM (100 and 500 μg/kg) were not significantly different. We detected a total of 44 VOCs among the treatments. The olfactometer bioassays showed no significant difference in the rates of attraction between different treatments.This study suggests that cattle dung does not experiment with a direct modification of the volatile compounds emitted, either via the digestive tract of cattle or by direct addition with IVM, ruling out the possible influence of any transformation product from the anthelmintic that could be present. In addition, a change in the microbiota of the digestive tract in cattle as a result of the mode of action of the drug is not supported. Further possible indirect effects are discussed. [ABSTRACT FROM AUTHOR]

Early detection and rapid response represent cornerstones of effective management of biological invasions, and development of methods that increase the sensitivity and efficiency of species detection directly benefit such efforts. We compared environmental DNA (eDNA) and canine scent detection of Dreissena polymorpha (Pallas, 1771), the Eurasian zebra mussel, in lakes of central Texas, USA. Environmental DNA analysis has become routinely incorporated as a component of D. polymorpha management programs; however, canine scent detection has typically been limited to inspection for adult mussels on watercraft. Thus, our work represents the first attempt to evaluate detection of D. polymorpha veligers (i.e., free-swimming larval stages) and other microscopic traces in environmental samples with canine scent detection. The specific objectives of this study were to: 1) evaluate whether canines can detect D. polymorpha in environmental samples; 2) quantify and compare limits of detection of canine scent detection and eDNA analysis; and 3) assess the performance of detection technologies through blind screening of ten lakes. In order of objective, our major findings include: 1) canines can be trained to detect D. polymorpha veligers in water samples; 2) eDNA detection is 2-100x more sensitive than canine scent detection; and 3) canine scent detection and eDNA both appear to outperform microscopy for D. polymorpha detection in environmental water samples. However, more work is needed to understand the conditions dictating when canine scent detection or eDNA outperforms the other. [ABSTRACT FROM AUTHOR]

Ceratitis capitata Wiedmann (Diptera: Tephritidae) is a significant pest of apricot (Prunus armeniaca) fruit in the spring and summer seasons in Türkiye. New integrated pest management techniques are required to reduce dependency on insecticides used for its control that may result in adverse environmental impacts. In the current study, we analyzed the volatiles emitted by apricot fruit using gas chromatography-mass spectrometry (GC-MS). We tested the behavioral responses of C. capitata to some of the identified compounds in the laboratory. Our results demonstrated that in four-arm olfactometer bioassays, C. capitata was more attracted to cis-3-hexenyl acetate and ethyl acetate than (Z)- 2-hexenyl butyrate and the control. In the wind tunnel, the landing rate on cis-3-hexenyl acetate was higher than those on (Z) -2-hexenyl butyrate and ethyl acetate. Our findings may support the development of attractants for novel control strategies against C. capitata in orchards. [Display omitted] • According to odor characterization results by SPME and GC-MS, 63 compounds were isolated from apricot volatiles. • The predominant volatile components were found to be cis -3-hexenyl acetate, ethyl acetate, and (Z)- 2-hexenyl butyrate. • Laboratory experiments confirmed that 3 compounds attracted more flies than the control. • The predominant volatile components of apricot can be a source of new Medfly kairomones as attractants of this pest. [ABSTRACT FROM AUTHOR]

Objective The study evaluated the potential of apple aroma to alleviate physiological stress response induced by a short-term cognitive stressor. It investigated the effects of apple aroma on cardiac and peripheral autonomic nervous system activity under stressful conditions.Methods Within-subject experiments were conducted with 25 healthy male university students with a 30-minute calculation task under three conditions: Apple, Chamomile (CHA), and Di propylene glycol (DPG) (scentless air). The aroma administration was precisely controlled and counterbalanced. Cardiac activity on electrocardiograms and nose tip temperature were recorded throughout the experiment. A visual analog scale and a scent questionnaire were subjective measures.Results Apple aroma demonstrated a significantly smaller increase in heart rate (t [24] = 3.36, p = 0.008 vs. DPG, t [24] = 4.06, p = 0.001 vs. CHA), and a decrease in the high-frequency component of heart rate variability (t [24] = 2.81, p = 0.029 vs. DPG, t [24] = 3.48, p = 0.006 vs. CHA) compared to the other conditions, representing a smaller enhancement of cardiac sympathetic nervous system activity and smaller suppression of cardiac parasympathetic nervous system activity respectively.Conclusion Apple aroma showed efficacy in alleviating the physiological stress response in terms of cardiac activity. Apple was also considered significantly preferable and comfortable compared to the other conditions, which would be beneficial in the context of aromatherapy.

The lineage G1 of Ganaspis brasiliensis is a larval parasitoid of the worldwide pest Drosophila suzukii and one of its most effective natural enemies in the native area. Because of its high degree of host specificity, G. brasiliensis G1 is considered a suitable species for introduction in areas invaded by D. suzukii following a classical biological control approach. Indeed, the release of the parasitoid is currently implemented in the USA and Italy. G1 females attack only host larvae developing in ripening fresh fruits on the plant and not larvae that develop in decaying fruits. To date, virtually no information is available on the cues regulating the foraging behavior of G1. In this study, we therefore aimed to find out whether chemical cues are exploited by G1 females to: (i) locate host fruits; (ii) locate suitable host larvae within infested fruit; (iii) discriminate between infested fresh fruits and infested rotting ones. We used a model system composed of blueberries and D. suzukii tested in two-choice olfactometer bioassays (with D. suzukii-infested fruits, healthy fruits, and pure air as odor targets), followed by the collection and the characterization of volatile organic compounds (VOCs) released by the tested targets. The results showed a clear time-dependent choice made by G1 females of infested versus healthy fruits related to the concomitant development of D. suzukii larvae and fruit degradation. Attraction to infested fruits was recorded during the early stages of infestation, followed by a repellent phase coinciding with fruits largely degraded by larval feeding. We found that the attractiveness of G. brasiliensis G1 towards fruits infested by young larvae was associated with the detection of VOCs released by the infested blueberries, and host’s cuticular hydrocarbons. Conversely, the repellence of older and deteriorated fruits hosting developed D. suzukii larvae was associated with the detection of a fermentation compound produced by microorganisms likely carried inside the fruit by the flies. The response of G1 females to the temporal dynamics of chemical cues emitted by the fruit–host larvae complex was consistent with the high degree of specificity of the parasitoid towards the ripening host fruits and towards D. suzukii.

The zoophytophagous mirid predator Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) is used in the augmentative biological control of Thrips palmi Karny (Thysanoptera: Thripidae), a fruit and vegetable pest in protected culture in Japan. N. tenuis can be maintained on certain plants without arthropod prey. Although such plant species may be useful as banker plants, their attractiveness to N. tenuis is underresearched. We investigated the behavioral responses of N. tenuis to (1) uninfested and conspecific-infested banker plants, Verbena × hybrida (verbena), Scaevola aemula (scaevola), Cleome hassleriana (cleome), and Lobularia maritima (sweet alyssum) and (2) conspecific-infested banker plants and T. palmi-infested eggplants, using a Y-tube olfactometer. Female N. tenuis preferred the volatiles emitted by (1) uninfested verbena over clean air but showed no preference for those emitted by the other uninfested banker plants, and (2) conspecific-infested verbena over clean air but showed no preference for those emitted by conspecific-infested scaevola over clean air. The attractiveness of the volatiles of T. palmi-infested eggplants for N. tenuis was not significantly different from those of N. tenuis-infested verbena and scaevola. As both uninfested and conspecific-infested verbena attracted female N. tenuis, this species is a promising banker plant. Chemical analyses and principal coordinate analyses of the volatiles from the headspaces of uninfested and N. tenuis-infested verbena and scaevola showed that 1-octen-3-ol, (E)-β-caryophyllene, and (E)-4,8-dimethyl-1,3,7-nonatriene distinguished these plant species and are candidate volatile N. tenuis attractants. [ABSTRACT FROM AUTHOR]

Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) is an important parasitoid of lepidopteran pests. Its parasitism success is related to its foraging behavior, mediated by kairomones from its hosts. We aimed to evaluate the chemotactic responses and parasitism of T. pretiosum from Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs as well as the parasitoid maintained for three generations in Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) eggs. Chemotactic responses of T. pretiosum from both hosts were evaluated in a dual choice olfactometer. Females were submitted to a choice between washed vs. unwashed eggs of E. kuehniella or S. frugiperda, as well as to unwashed eggs of both hosts. Egg extracts of both hosts were also contrasted with hexane and with each other. Parasitism of T. pretiosum exposed to eggs of the two species was also evaluated. Females from E. kuehniella were more attracted to odors from eggs of this host whenever it was present. Third generation parasitoids from S. frugiperda eggs were more attracted to eggs and egg extract of S. frugiperda than to those from E. kuehniella. The highest number of parasitized eggs and emerged parasitoids in S. frugiperda was observed in parasitoids coming from the third generation in this host. Therefore, imaginal conditioning could be an alternative to be considered for T. pretiosum learning before releasing, possibly optimizing its search and parasitism process in S. frugiperda eggs. [ABSTRACT FROM AUTHOR]

The generalist predator Nesidiocoris tenuis, an effective biological control agent of numerous pests of the tomato crops, can also trigger plant defence mechanisms (direct and indirect) due to its phytophagous behaviour. In southern Europe, Nesidiocoris tenuis is frequently released in tomato greenhouses to control the invasive pest Tuta absoluta, sometimes combined with another biocontrol agent, the egg parasitoid Trichogramma achaeae. In this study, using olfactometer bioassays, we showed that the modification of the volatile chemical profile induced by the plant feeding activity of the mirid made tomato plants more attractive to T. achaeae, both in the absence and in the presence of T. absoluta eggs or larvae. This result was discussed in relation to difference observed among the chemical profiles of the volatile organic compounds released by tomato plants punctured by N. tenuis, without or in combination with T. absoluta infestation. We found that a few compounds (e.g.β-pinene and myrcene) could play a role in the foraging behaviour of T. achaeae in this scenario. Overall, our data support the emerging idea of an ecological role of N. tenuis, in addition to its predatory activity, in making tomato crops more resilient against the attack of pests, including T. absoluta. [ABSTRACT FROM AUTHOR]

The behaviour and orientation modifying cues from host plants and prey insects play vital roles in the process of host selection and acceptance by predators. So, we studied the volatile organic compounds of un-infested and infested cabbage plants by cabbage aphid, Brevicoryne brassicae, through Gas Chromatography-Mass Spectrometry (GC-MS). Overall, 58 and 50 compounds were identified in uninfested and infested cabbage plants through DCM and DEE extract, respectively. Based on the peak area from the GC-MS analysis, the volatile organic compounds from infested cabbage were significantly greater than that from un-infested cabbage extract. In the DCM extract, volatile compounds, notably Cyclohexasiloxane tetradecamethyl, Cyclopentasiloxane decamethyl, and 3-Hexen-1-ol were released in significant amounts. In the DEE extract, 3-Hexen-1-ol, (Z)-, Cyclohexasiloxane dodecamethyl, and Cyclopentasiloxane decamethyl were also released in substantial quantities. The Y-tube olfactometer study revealed that C. sexmaculata adults exhibited significantly greater attraction to the volatiles emitted from cabbage infested with aphids compared to any other extract. Additionally, their response time was notably shorter when exposed to the infested cabbage with aphid extract. The results indicated that the C. sexmaculata could discriminate the infested cabbage and significantly responded to the plant odour, which suggested that, the synomones (volatiles from cabbage plant) and kairomones (volatiles from aphid body) played a vital role in the orientation behaviour of C. sexmaculata to locate the cabbage aphid. [ABSTRACT FROM AUTHOR]

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The olive fruit fly (Bactrocera oleae) (Rossi) is the most economically important insect pest in many olive cultivation areas worldwide. However, levels of infestation by this pest show remarkable variability, even among orchards in close proximity to one another. While the factors driving this variability remain uncertain, there is evidence that the presence of native plants species can influence pest populations in agro‐ecosystems via various mechanisms, suggesting that variation in the composition of understorey plant communities might plausibly play a role. In this study, we first used field trapping and plant community surveys to explore the effect of the native understorey plants Cistus creticus (Cistaceae), Lavandula stoechas (Lamiaceae), Origanum onites (Lamiaceae) and Sarcopoterium spinosum (Rosaceae) on the abundance of B. oleae across 40 olive orchards on Lesvos Island (Greece). These four plant species are widely spread in many olive orchards. Our results revealed a relationship between the plant community and the intensity of flies captured in McPhail traps, and identified the plant species C. creticus and S. spinosum whose presence was negatively correlated with fly abundance (estimate = −0.047, −0.091, respectively). The subsequent laboratory behavioural experiments revealed that exposure to olfactory cues from C. creticus and S. spinosum reduced fly attraction to odours from the olive host (Olea europaea) by 10%. These results thus reveal a relationship between the infestation levels by B. oleae and the composition of the plant community in olive orchards on Lesvos and suggest a plausible mechanism via which olfactory cues from native aromatic species might influence fly recruitment. More generally, these findings highlight the potentially important role of understorey communities in mediating resistance to B. oleae and other agricultural pests. [ABSTRACT FROM AUTHOR]

Plant herbivore interactions have long been recognized as a complex interplay influenced by various factors, including plant volatile emissions. Understanding the role of these volatiles in mediating plant predator interactions is crucial for developing sustainable pest management strategies. This study investigated the olfactory preferences of Chrysoperla externa larvae for volatiles emitted by Eucalyptus urograndis leaves, focusing on both seedlings and essential oils (EOs). We used Y-tube olfactometry to compare larval preferences between the clean air and various plant treatments, including undamaged and herbivore-damaged leaves. Chemical analysis of EOs revealed higher concentrations of oxygenated monoterpenes and sesquiterpenes in young and damaged leaves, particularly linalool, which has been implicated in insect attraction. Our results showed a significant preference for volatiles emitted by young damaged leaves over clean air for both seedlings (χ2 = 11.03, p = 0.001) and EOs (χ2 = 9.76, p = 0.002). Chrysoperla externa larvae are significantly attracted to specific volatiles from damaged E. urograndis leaves, suggesting these compounds could serve as cues for natural enemy foraging. Our findings enhance the understanding of plant–predator dynamics and suggest potential applications of eucalyptus plantations to sustain C. externa populations for biocontrol purposes.

Olfactometers have been used for more than 100 years and are integral to experimental chemical ecology. Studies utilising olfactometer bioassays form the foundation for understanding the behavioural responses of invertebrates to chemical stimuli under standardised laboratory conditions. Widely used olfactometry apparatuses include two‐arm olfactometers for binary responses through to four‐ and six‐arm arenas to evaluate more complex behaviours. Despite its prevalence in chemical ecology studies, there has never been a review of experimental best practice in olfactometry. This review critically evaluates both olfactometry methods and applications as well as experimental design and analysis. We aim to outline a standard of good practice to improve experimental design and reporting for studies involving olfactometry, thereby establishing a reference guide to build a robust experimental workflow for olfactometry bioassays. [ABSTRACT FROM AUTHOR]

The article "Host Preference Evaluation of Varroa destructor on Apis mellifera by Air-Flow Olfactometer" discusses the behavior of Varroa destructor, a parasitic mite, on different stages of honeybees. The study found that the mites were most attracted to drone bees and drone larvae, while they were less interested in forager bees. This information could be useful in developing strategies to manage Varroa mite populations and promote the health of honeybee colonies. However, more research is needed to fully understand and implement these methods. [Extracted from the article]

Globally, Aedes mosquitoes cause morbidity and mortality of dengue, yellow fever and other arboviral infections. There is no effective vaccine for Aedes transmitted diseases so mosquito control remains the mainstay for their control. Semiochemicals play significant role in modulating insect behavior so are utilized to lure mosquitoes to their destruction or to repel them to halt infection transmission. Palm wines are potent source of semiochemicals but their effect on Aedes mosquitoes in our locality is not well understood. This study was undertaken to ascertain whether palm wine could impact on mosquito inflections. Aedes larvae were collected and bred in the laboratory to adulthood. Female mosquitoes were selected and tested for their reactions to two categories of palm wine - the up-palm and down-palm wines. An olfactometer was fabricated and applied to find how Aedes mosquitoes reacted in it when subjected to odours from the palm wines within 5 minutes. Data obtained were prepared and one way analysis of variance was used to compare means. Only 3% of mosquitoes reached the up-wine arm on day 2. However, when both wines were tested, 2.78 ± 2.78% of mosquitoes reached the down-palm wine terminal. Both wines repelled mosquitoes consistently, confirmed by their refusal to seek any of the palm wine odours. Repellence increased as days passed: initially upstream mosquitoes ranged 36.36 - 60% at the beginning, declining to 3.3 - 6.36% on the 8th day; whereas downstream ranged from 40 - 63.63% at the beginning to reach 93.63 - 100% on the 8th day. Palm wines semiochemicals repelled Aedes mosquitoes. Further testing may be required before utilization in formulated repellents for public use. [ABSTRACT FROM AUTHOR]

The rice moth, Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae), is a serious pest of grains in storage systems resulting in immense losses but is also widely used as a factitious host for mass rearing of many important natural enemies of crop pests. Given the role of kairomones, the aim of this study was to isolate and identify potential cues from the larval body wash of C. cephalonica, which could attract its gregarious ectoparasitoid, Habrobracon hebetor (Say) (Hymenoptera: Braconidae). Gas chromatography with electroantennography (GC-EAG) and olfactory assays were used to demonstrate the attraction of female H. hebetor to different larval body volatiles. A total of 15 EAG-active compounds were discovered in the body wash of C. cephalonica larvae that triggered a response in female H. hebetor. Among them, four compounds (p-xylene, naphthalene, n-eicosane and n-tricosane) were bioassayed for the behavioural response of parasitoids and found that n-eicosane significantly attracted a higher number of parasitoids than others. Our work establishes the attraction of H. hebetor to volatile kairomone cues emanating from the factitious host larval body, which offers an opportunity for its parasitoid, H. hebetor to improve the mass rearing efficiency. [ABSTRACT FROM AUTHOR]

The foraging behavior of the infective juveniles (IJs) of entomopathogenic nematodes (EPNs) relies on host-derived compounds, but in a tri-trophic context, herbivore-induced root volatiles act as signals enhancing the biological control of insect pests by recruiting EPNs. In southern Chile, the EPN Steinernema australe exhibits the potential to control the raspberry weevil, Aegorhinus superciliosus, a key pest of blueberry Vaccinium corymbosum. However, there is no information on the quality of the blueberry root volatile plume or the S. australe response to these chemicals as putative attractants. Here, we describe the root volatile profile of blueberries and the chemotaxis behavior of S. australe towards the volatiles identified from Vaccinium corymbosum roots, infested or uninfested with A. superciliosus larvae. Among others, we found linalool, α-terpineol, limonene, eucalyptol, 2-carene, 1-nonine, 10-undecyn-1-ol, and methyl salicylate in root volatiles and, depending on the level of the emissions, they were selected for bioassays. In the dose–response tests, S. australe was attracted to all five tested concentrations of methyl salicylate, 1-nonine, α-terpineol, and 2-carene, as well as to 100 µg mL−1 of 10-undecyn-1-ol, 0.1 and 100 µg mL−1 of linalool, and 100 µg mL−1 of limonene, whereas eucalyptol elicited no attraction or repellency. These results suggest that some volatiles released from damaged roots attract S. australe and may have implications for the biocontrol of subterranean pests. [ABSTRACT FROM AUTHOR]

Plants' essential oils play a considerable role in the plant integrated protection systems against harmful insects. Therefore the aim of our study was to find the potential repellency and toxicity effects of essential oils (EOs) from Allium sativum L., Ocimum basilicum L., Lavandula angustifolia Mill, Eucalyptus globulus, Labill and Curcuma longa L., and two chemical substances DEET (N, N-diethyl-3-methylbenzamide) and 2-Undecanone on the black cherry aphids Myzus cerasi. Repellent peculiarities were evaluated at five different concentrations: 0.3%, 0.6%, 0.9%, 1.2% and 1.5%, with 4 replications at the interim of 15 and 30 minutes for an olfactometer test and mortality was evaluated after 2, 6 and 24 hours for insecticidal activity test. The repellent index was most influenced by the concentration of essential oil; the percentage of influence was 64%. At the same time, the highest repellency index 95% was achieved at a concentration of 1.5% when using essential oils of A. sativum and E. globulus, as well as when using 2-Undecanone within 30 minutes of waiting. A contact toxicity (mortality) test in Petri dishes showed efficacy for all tested oils and chemicals after a 6-hour treatment period. The lowest concentration that ensured 100% insect mortality was 0.9% when using E. globulus essential oil. The lowest lethal concentration (LC50) value of 0.00240 mL/10 mL was obtained with O. basilicum oil and the lowest LC98 value of 0.28209 mL/10 mL was obtained with E. globulus oil after a 6-hour treatment period. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding insect olfactory perception can lead to more effective and specific ways to manage pests. In fact, odors have two components: (1) the quality, defined as its chemical composition, and (2) the quantity, defined by the concentration of the odor. The quantitative aspect is often missing and we aim to provide valuable information on the quantitative aspect of the odors that attract the western flower thrips, an insect that damages crops. In this study, we tested how the western flower thrips responded to different odors in an olfactometer. We measured the odor concentrations carried by the air and found that the thrips were most attracted to a pheromone at very low concentrations, much lower than the other odors we tested. Our results show that the attraction of western flower thrips to an odor depends on its quantitative aspect and could help to develop better ways of managing this pest. An understanding of insect olfaction allows for more specific alternative methods of pest control. We evaluated the responses of the western flower thrips (WFT, Frankliniella occidentalis) in a Y-olfactometer to estimate gas-phase concentrations of the aggregation pheromone neryl (S)-2-methylbutanoate and known kairomones such as methyl isonicotinate, (S)-(-)-verbenone, and p-anisaldehyde. The gas-phase concentrations of these compounds were obtained from the release rates measured in dynamic headspace cells. The compounds were collected from the headspace using dried solid-phase extraction (SPE) cartridges and analyzed with a triple quadrupole GC-MS/MS. We observed that the aggregation pheromone significantly attracted WFT females at doses of 10 and 100 µg, whereas methyl isonicotinate and p-anisaldehyde significantly attracted WFT females at the highest dose. Verbenone did not produce any significant results. A completely different picture was obtained when the gas-phase concentrations were considered. The minimal gas-phase concentrations of the pheromone required to attract WFT females was 0.027 ng/mL, at least 100 times lower than that of the other two compounds. The relevance and implications of our results are discussed in light of the insect's biology and pest management methods. [ABSTRACT FROM AUTHOR]

This study was conducted in 2013–2014 in order to determine the response of the egg parasitoid, Trissolcus semistriatus (Nees) (Hymenoptera: Scelionidae) to metathoracic scent gland (MSG) extract from Eurygaster maura (L.) (Hemiptera: Scutelleridae) in laboratory conditions. For this purpose, the MSG extracts obtained separately from males and females were diluted with hexane and six different concentrations were prepared. Naïve, mated parasitoids (2-3 days old) were used in the experiments. Hexane and distilled water were used as control treatments. In a Y-tube olfactometer, low concentrations of MSG extract from both sexes attracted the T. semistriatus but the preference for MSG extract was reduced with the increase in extract concentration and parasitoids oriented towards clean air. In order to determine the effect of MSG extract of E. maura on parasitisation and emergence rates of T. semistriatus, a single parasitoid was presented with two egg masses on blotting paper treated with MSG extract and two on blotting paper treated with hexane 4 cm apart in a Petri dish. The parasitoid was allowed 24 h for parasitisation. Parasitisation rates were higher than control at low concentrations of MSG extract of both sexes. There was no effect of MSG extracts on the emergence rates of parasitoids from eggs. According to the present results, the performance of the egg parasitoid, T. semistriatus in the control of the sunn pest, E. maura, can be enhanced by MSG extracts of the pest. [ABSTRACT FROM AUTHOR]

Herbivore-induced volatiles were extracted from fresh healthy jasmine plants (Jasminum sambac L.) and infested jasmine plants damaged by two-spotted spider mite, Tetranychus urticae and analyzed through Gas Chromatography- Mass spectrometry (GC-MS) to determine volatile hydrocarbon profile in them. Further, olfactometer behavioral bioassay was conducted to investigate the preference of the predator, Scolothrips sexmaculatus to the emitted volatiles. The results revealed that both the healthy and plants infested with two-spotted mites had emitted organic volatile compounds (VOC's) numbering 19 and 31 respectively and some compounds were detected twice or even thrice. The variation in the volatile constituents of healthy and damaged plants clearly depicts the emission of volatiles responsible for attracting beneficials witnessing tritrophic interactions in jasmine ecosystem. The mite infested plants emanated potential natural enemy attractants such as ally isothocyanate, styrene, naphthalene, Bis (2-ethylhexyl) phthalate and several other organic compounds. The compound allyl isothiocyanate was detected in two-spotted mite infested jasmine extracts at 4.307 mts in a peak area of 1664139 mm2. Allyl isothiocyanate serves the plant as a defense against herbivores; since it is harmful to the plant. Bis (2-ethylhexyl) phthalate, a six-carbon compound was detected due to herbivory of mite infested plants in a peak area of 4112779391 mm2 implying its maximum presence. Dicacodyl phthalate, another compound, was detected in a peak area of 20400249 mm² at 30.97 mins. The healthy jasmine plants emanated natural enemy attractants, linalool, methyl salicylate and alpha-farnesene, aside from other volatile organic compounds. In the olfactometer behavioural bioassay studies, maximum number of released mite predator, S. sexmaculatus, oriented on mite infested jasmine plant volatiles (18.5 nos), and healthy plant volatiles (5.5 nos). The volatile organic compounds detected in enormous quantities in mite infested jasmine plants is a positive cue for commercial preparation of artificial lures to attract mite natural enemies in jasmine ecosystem. The predatory thrips lured to mite infested volatiles enrolls an encouraging sign to be exploited in integrated management of mites to enhance the efficacy of potential natural enemies of two-spotted spider mites. [ABSTRACT FROM AUTHOR]

Spatial repellents are emerging as a promising approach to reduce vector-disease burden; however, the evolution of genetically resistant mosquitoes decreases repellent efficacy. The development of flight chambers to investigate spatial repellent application techniques is vital for sustainable mosquito control. We present an air-dilution chamber as a novel bioassay to study mosquito flight behavior responses to chemical gradients of the volatile, pyrethroid transfluthrin (TF). Air dilution was used to simulate a larger environment of stable concentration gradients verified with carbon dioxide (CO2) which was homogenously delivered and measured across the chamber to achieve a 5× inlet/outlet [CO2] ratio with 0.17 m/s outlet velocity. Female Aedes (Ae.) aegypti (Diptera: Culicidae, Linnaeus, 1762) were exposed to volatilized TF paired with heat, CO2, and Biogents-Sweetscent host-cues. Tandem solvent extraction-gas chromatography-mass spectrometry (SE-GC-MS) was used to quantify air samples taken during TF emanations with a limit of detection (LOD) and quantification (LOQ) of 2 ± 1 and 5 ± 2 parts-per-trillion (ppt) TF, respectively. Homogenous air diluted emanation of the spatial repellent TF was at least twice that of the 5× CO2 gradient with the same air flow in the chamber. The airborne TF concentrations the mosquitoes were exposed to range from 1 to 170 ppt. Video recordings of mosquito behavior during host-cues exposure revealed increased inlet activity, while exposure to TF protected host resulted in decreased inlet activity over time with inlet-outlet mosquito positional variation. This novel flight chamber design can simulate 'long'-range exposure with simultaneous quantitation of airborne spatial repellent to understand dose-dependent effects on mosquito behavior. [ABSTRACT FROM AUTHOR]

Green plant bugs Apolygus lucorum Meyer‐Dür (Hemiptera: Miridae) are among the most important piercing‐sucking insect pests of the tea plant Camellia sinensis (L.) O. Kuntze (Theaceae) and severely reduce the quality and economic benefits of tea. The preference of A. lucorum for tea plants and weed hosts, including Humulus scandens (Lour.) (Moraceae), Artemisia lavandulaefolia DC., Conyza canadensis (L.) Cronq, and Artemisia annua L. (all Asteraceae), was evaluated using an olfactometer bioassay. Volatiles from weed host plants were analyzed by electronic nose and gas chromatography/mass spectrometry. The A. lucorum adults had a significant preference for the volatiles from A. lavandulaefolia compared to volatiles from tea. Myrcene, 1,8‐cineole, and sabinene were the three dominant components in the A. lavandulaefolia flower volatiles. Artemisia lavandulaefolia was selected as a trap plant to assess the attractiveness to A. lucorum and the effects on natural enemies. The population density of A. lucorum on A. lavandulaefolia planted in tea plantations was significantly higher than that on tea. In particular, in tea fields with A. lavandulaefolia at 2 m spacing, the number of A. lucorum on trap strips of A. lavandulaefolia was higher than on tea at 10, 20, and 30 m away from the trap strips. The trap strips of A. lavandulaefolia also promoted a small increase in the presence of natural enemies in the tea agroecosystem, especially lacewings. Our research indicated that planting A. lavandulaefolia as a trap plant at 2 m spacing has the potential to manipulate the population of A. lucorum in tea plantations. [ABSTRACT FROM AUTHOR]

The objective of this study was to understand the role of Cosmopolites sordidus in the dispersal of Fusarium oxysporum f. sp. cubense race 1 (Foc) and more specifically to determine whether C. sordidus is preferentially attracted to Foc‐contaminated banana plant material vs. Foc‐free material. The attraction of C. sordidus to healthy and Foc‐contaminated Gros Michel banana bulbs and pseudostems, as well as to pure cultures of Foc, was compared using four‐choice olfactometers. Males and females were studied separately. After storage in a dark room, weevils were placed in the central chamber of olfactometers. After 15 min, the orientation of each of the weevil was determined according to the food source located in each of the four peripheral chambers of the olfactometer. Overall, 560 olfactometer assays were carried out. Weevils were found to prefer Foc‐infected plant tissues. Weevil preference was not significantly affected by weevil sex. The attraction of C. sordidus to Foc‐contaminated plant material suggests that this insect could be important for the dissemination of Foc, especially in early stages of epidemics, when Foc‐infected plants are scarce. [ABSTRACT FROM AUTHOR]

Potency of kaffir lime leaves essential oil as botanical fumigant against Araecerus fasciculatus (De Geer) (Coleoptera: Anthribidae) in cocoa bean storages. Cocoa (Theobroma cacao) is one of the important commodities in Indonesia. The quality of cocoa beans has decreased during storage, one of which is due to the attack of Araecerus fasciculatus (De Geer). This pest attack can be overcome by fumigation that is safe for the environment through the use of essential oil. The study aimed to examine the mortality and repellent effects of kaffir lime leaves essential oil (KLLEO) to A. fasciculatus and to analyze the compound content of active fraction KLLEO using GC-MS. Research stages included maintenance and insect rearing, toxicity and repellency tests, fractionation, and analysis of active fraction compounds of essential oils. The study was designed using CRD with 6 treatments and 4 replications. The n-hexane fraction of KLLEO caused the highest mortality of A. fasciculatus adults after 72 hours of fumigation. The LD50 and LD95 values of the n-hexane fraction of KLLEO were 0.30 and 1.66 ml/l air, respectively. The dose at 1 ml/l air caused the highest mortality of A. fasciculatus adult by 73.75%. Examine using an olfactometer, KLLEO has high repellency against adult A. fasciculatus with the value of the repellency index reaching 100% at 1 ml/l air. The most dominant compound in the n-hexane fraction of KLLEO was the citronellal. Therefore, the KLLEO has some potential to be expanded as a botanical fumigant towards A. fasciculatus.

Trichogramma spp. (Hymenoptera: Trichogrammatidae) are generalist egg parasitoids widely used as biological control agents, yet with limited efficacy against Tuta absoluta (Meyrick; Lepidoptera: Gelechiidae), a key pest of tomato. Olfactory cues related to the host-plant complex influence the searching behavior in parasitoids. Studies have shown that female Trichogramma spp. can learn odor cues affecting their preference. We assessed if learning increases the response to tomato odor and whether it improves the parasitism rate of Trichogramma achaeae, Trichogramma evanescens, and Trichogramma dendrolimi. The parasitoids were either naive, reared for one generation on T. absoluta eggs, or conditioned associatively with an oviposition experience on a factitious host in the presence of tomato odor. Subsequently, their arrestment response (searching time) to T. absoluta-infested tomato leaves was observed in a static four-chamber olfactometer. Rearing the parasitoids on T. absoluta increased the arrestment time of T. dendrolimi strongly and that of T. evanescens slightly but not that of T. achaeae. In contrast, oviposition experience on a factitious host with the tomato odor (leaves or extract) increased the searching time of T. achaeae and T. evanescens strongly but did not improve the response of T. dendrolimi. Concerning parasitism improvement, only T. achaeae showed an increased parasitism rate after associative learning. Hence, the learning capacity of T. achaeae should be further explored to improve its biological control efficacy against T. absoluta. [ABSTRACT FROM AUTHOR]

The presence of a perceptual bias due to anxiety is well demonstrated in cognitive and sensory task for the visual and auditory modality. Event-related potentials, by their specific measurement of neural processes, have strongly contributed to this evidence. There is still no consensus as to whether such a bias exists in the chemical senses; chemosensory event-related potentials (CSERPs) are an excellent tool to clarify the heterogeneous results, especially since the Late Positive Component (LPC) may be an indicator of emotional involvement after chemosensory stimulation. This research examined the association between state and trait anxiety and the amplitude and latency of pure olfactory and mixed olfactory–trigeminal LPC. In this study, 20 healthy participants (11 women) with a mean age of 24.6 years (SD = 2.6) completed a validated questionnaire to measure anxiety (STAI), and CSERP was recorded during 40 pure olfactory stimulations (phenyl ethanol) and 40 mixed olfactory–trigeminal stimulations (eucalyptol). LPC latency and amplitude were measured at Cz (electrode located at midline central) for each participant. We observed a significant negative correlation between LPC latencies and the state anxiety scores for the mixed olfactory–trigeminal condition (r (18) = −0.513; P = 0.021), but not for the pure olfactory condition. We did not observe any effect on LPC amplitudes. This study suggests that a higher level of state anxiety is related to a more rapid perceptual electrophysiological response for mixed olfactory–trigeminal stimuli but not for pure odors. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Sudden outbreaks of the orange wheat blossom midge, Sitodiplosis mosellana (Géhin) cause huge wheat yield losses. Use of sex pheromones is more efficient than laborious egg counting to monitor these hidden‐concealed insects. Quick synthesis of the sex pheromones is therefore required to meet the sudden outbreak needs. RESULTS: A synthetic approach of stereospecific and racemic S. mosellana pheromones was presented. This method afforded the stereospecific and racemic S. mosellana pheromones in three steps and high enantioselectivity (> 98% ee for (2S,7S)‐2,7‐nonanediyl dibutyrate) in less than 1 day with 74% and 73% overall yields, respectively, whereas most conventional methods require longer synthesis time with less than 40% yield. The synthesis routes could quickly and economically afford the pheromones, starting from synthon (S)‐but‐3‐yn‐2‐ol (1a) or but‐3‐yn‐2‐ol (1b), through the same three‐step processes of coupling, reduction, and esterification. The Y‐tube olfactometer results showed significant attractiveness of the synthetic stereospecific and racemic sex pheromones to S. mosellana males relative to the blank control (P < 0.001). Field trials also demonstrated significant attractiveness of the synthetic stereospecific and racemic sex pheromones relative to the blank control (P < 0.001). CONCLUSION: This modular approach is conducive to the deployment of field traps and timely responses to S. mosellana outbreaks and can be a time‐saving and cost‐effective tool to manage S. mosellana. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

• A new stragic analytical tools to resolve the challenges of miniaturization devices. • Real-time monitoring of chemical and biological markers. • In-vitro & in-vivo system-level solution along with the world of internet-of-things. • A micro- and nano- systems approach for sensing and actuation technologies. Bio-inspired electronic sensors, including E-tongue, E-noses, E-eyes, and E-skin sensors, are revolutionizing healthcare and industries by mimicking human sensory organs for precise detection and identification of stimuli. These sensors use sensor arrays and pattern recognition algorithms to replicate human taste and smell, ensuring consistent quality and safety in food and beverage products. Field olfactometers, an extension of E-nose technology, enable real-time, on-site odor concentration measurements, enhancing environmental monitoring capabilities. E-eyes, grounded in optics and semiconductor technology, offer rapid, accurate assessments of food quality by analyzing parameters like size, shape, and color, improving quality control processes in food production and skin-inspired electronics, designed to integrate with human skin, provide advanced functionalities in wearable devices, human–machine interfaces, healthcare monitoring systems, artificial prosthetics, and robotic tactile perception. These conformal devices have significant potential for continuous health monitoring and interactive applications, fostering advancements in personalized medicine and assistive technologies. In this review, development and application of bio-inspired electronic sensors represent a significant leap forward in healthcare technology, offering sophisticated, reliable solutions for real-time monitoring and quality control across various domains. [ABSTRACT FROM AUTHOR]

Entomopathogenic fungi (EPF) are the most important category of microbial agents and considered to be crucial elements in biological control. In this study, two species of EPF, Cladosporium sp. AF98 (Ascomycota: Davidiellaceae) and Acremonium zeylanicum IR87 (Petch) W. Gams & H.C. Evans (Ascomycota: Hypocreaceae), were isolated from infected individuals of the citrus cottony scale, Pulvinaria aurantia Cockerell (Hemiptera: Coccidae), and the melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), respectively. Based on the nucleotide sequence of the ribosomal DNA, the fungal isolates were subjected to molecular identification and phylogenetic analysis. Pathogenicity of the fungal isolates to the black bean aphid, Aphis fabae Scopoli, was evaluated under laboratory conditions. Both fungal isolates caused considerable aphid mortality and no significant differences were observed in pathogenicity of the isolates. The severity of the fungal isolate effect on the aphid increased as the conidial concentration increased. Time was found to be a more important factor than conidia concentration in isolate efficacy. Olfactory experiments indicated that Lysiphlebus fabarum Marshall (Hymenoptera: Braconidae, Aphidiinae), an important parasitoid wasp of A. fabae, can detect cues from the fungus‐infected aphids and can avoid them. Therefore, fungal isolates have considerable potential for the microbiological control of the aphid and are also compatible with other means of biological control of the pest. [ABSTRACT FROM AUTHOR]

The spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) is a polyphagous, phloem-feeding invasive forest, agricultural, and nuisance pest that is rapidly spreading through the U.S. Little is known about how fulgorids locate each other to mate. To determine if conspecific semiochemicals such as pheromones occur, whole body extracts (WBE) of adult spotted lanternflies from different physiological states were tested for attraction in a dual-choice olfactometer. In olfactometer assays, prior to mating, males were oriented to WBE from males and females. During their mating period, males were attracted to WBE of females, but not to that of males. After mating and oviposition had taken place, males were not attracted to either male or female extracts. Conversely, females did not orient to any WBE from either sex during any physiological state. These behavioral responses by males but not females to WBE from conspecifics in different physiological states suggest the possible presence of an aggregation-sex pheromone in the spotted lanternfly. [ABSTRACT FROM AUTHOR]

As primary producers, plants play a central role in mediating interactions across trophic levels. Although plants are the primary food source for herbivorous insects, they can protect themselves from herbivore damage. Many plants produce toxic compounds that directly reduce herbivore feeding, but plants also protect themselves indirectly by attracting natural enemies of the attacking herbivore through volatile signaling. These so-called tri-trophic interactions have historically been documented aboveground in aerial plant parts but are also known to occur belowground in root systems. In addition to herbivores, plants directly interact with other organisms, which can influence the outcomes of tri-trophic interactions. Arbuscular mycorrhizal fungi (AMF) are symbiotic soil microbes that colonize the roots of plants and facilitate nutrient uptake. These microbes can alter plant chemistry and subsequent resistance to herbivores. Few studies, however, have shown how AMF affect tri-trophic interactions above- or belowground. This study examines how AMF colonization affects the emission of root volatiles when plants are under attack by western corn rootworm, a problematic pest of corn, and subsequent attraction of entomopathogenic nematodes, a natural enemy of western corn rootworm. Mycorrhizal fungi increased rootworm survival but decreased larval weight. Differences were detected across root volatile profiles, but there was not a clear link between volatile signaling and nematode behavior. Nematodes were more attracted to non-mycorrhizal plants without rootworms and AMF alone in soil, suggesting that AMF may interfere with cues that are used in combination with volatiles which nematodes use to locate prey., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The red flour beetle, Tribolium castaneum (Herbts) is a major pest of flour from various grains. The infested flour is discoloured and will emit a disagreeable odour due to the secretion of benzoquinone from the insect’s abdominal glands. Considering the economic losses effected by T. castaneum, new alternative control measures are needed for this pest. This study sought to determine the host preferences of T. castaneum from amongst six kinds of flour to assess their vulnerability to infestation. The research was conducted in the Plant Pest Laboratory, Department of Plant Pests and Diseases, Faculty of Agriculture, University of Brawijaya. The host preferences of T. castaneum were examined using a six-arm olfactometer. Feeding preference tests were performed for a duration of 12 hours at 200 ml/minute airflow in each chamber-arm, followed by oviposition preference observations one week later. Feeding preference was calculated for the total pool of adults observed, segregated by sex, whereas oviposition preference was calculated as the number of eggs laid. Flour nutrition (proximate composition, phenolic content, and riboflavin content) were analyzed. Our results showed a feeding preference by T. castaneum for bran, soy and tapioca flour was greater over wheat, corn, and white gelatinous rice flour, while for oviposition, bran flour was the most preferred.

Abstract Background Understanding the ecology and behaviour of disease vectors, including the olfactory cues used to orient and select hosts and egg-laying sites, are essential for the development of novel, insecticide-free control tools. Selected graminoid plants have been shown to release volatile chemicals attracting malaria vectors; however, whether the attraction is selective to individual plants or more general across genera and families is still unclear. Methods To contribute to the current evidence, we implemented bioassays in two-port airflow olfactometers and in large field cages with four live graminoid plant species commonly found associated with malaria vector breeding sites in western Kenya: Cyperus rotundus and C. exaltatus of the Cyperaceae family, and Panicum repens and Cynodon dactylon of the Poaceae family. Additionally, we tested one Poaceae species, Cenchrus setaceus, not usually associated with water. The volatile compounds released in the headspace of the plants were identified using gas chromatography/mass spectrometry. Results All five plants attracted gravid vectors, with the odds of a mosquito orienting towards the choice-chamber with the plant in an olfactometer being 2–5 times higher than when no plant was present. This attraction was maintained when tested with free-flying mosquitoes over a longer distance in large field cages, though at lower strength, with the odds of attracting a female 1.5–2.5 times higher when live plants were present than when only water was present in the trap. Cyperus rotundus, previously implicated in connection with an oviposition attractant, consistently elicited the strongest response from gravid vectors. Volatiles regularly detected were limonene, β-pinene, β-elemene and β-caryophyllene, among other common plant compounds previously described in association with odour-orientation of gravid and unfed malaria vectors. Conclusions The present study confirms that gravid Anopheles gambiae sensu stricto use chemical cues released from graminoid plants to orientate. These cues are released from a variety of graminoid plant species in both the Cyperaceae and Poaceae family. Given the general nature of these cues, it appears unlikely that they are exclusively used for the location of suitable oviposition sites. The utilization of these chemical cues for attract-and-kill trapping strategies must be explored under natural conditions to investigate their efficiency when in competition with complex interacting natural cues. Graphical abstract

An understanding of insect olfaction allows for more specific alternative methods of pest control. We evaluated the responses of the western flower thrips (WFT, Frankliniella occidentalis) in a Y-olfactometer to estimate gas-phase concentrations of the aggregation pheromone neryl (S)-2-methylbutanoate and known kairomones such as methyl isonicotinate, (S)-(-)-verbenone, and p-anisaldehyde. The gas-phase concentrations of these compounds were obtained from the release rates measured in dynamic headspace cells. The compounds were collected from the headspace using dried solid-phase extraction (SPE) cartridges and analyzed with a triple quadrupole GC-MS/MS. We observed that the aggregation pheromone significantly attracted WFT females at doses of 10 and 100 µg, whereas methyl isonicotinate and p-anisaldehyde significantly attracted WFT females at the highest dose. Verbenone did not produce any significant results. A completely different picture was obtained when the gas-phase concentrations were considered. The minimal gas-phase concentrations of the pheromone required to attract WFT females was 0.027 ng/mL, at least 100 times lower than that of the other two compounds. The relevance and implications of our results are discussed in light of the insect’s biology and pest management methods.

Floral volatiles are among the well‐known cues that mediate plant‐pollinator interactions. Understanding plant‐pollinator interactions is especially important in arid regions, where the low abundance of pollinators limits their visiting frequency and, thus, constraints the reproductive success of many plant species. Moreover, plants in such arid habitats are exposed to abiotic stress, particularly to water shortage. Plants in arid habitats are also prone to suffer from multiple stress factors, such as the addition of pathogen and herbivore attacks. All these stress factors induce disruptions in the plant metabolism and increase physiological costs that may lead to changes in floral volatiles, thus affecting the communication between the plant and its pollinators, consequently intensifying the constraints on the plants' reproductive success. To explore this general hypothesis, we used as a model Matthiola livida (Delile) DC. (Brassicaceae), a common native plant species in arid regions of the Middle East. We first tested whether water shortage and insect herbivory, inflicted by whiteflies, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), caused stress in M. livida, based on the change in carbohydrates and starch content, and examined whether the plants produced distinct volatile composition in response to these stressors. Then, we tested whether bumblebees, Bombus terrestris (L.) (Hymenoptera: Apidae), common pollinators of M. livida, were able to differentiate between plants suffering from water shortage and insect herbivory based only on volatile emission. We found that both water shortage and insect herbivory caused stress in the plants. We also found that the plants produced a distinct volatile composition in relation to the specific stress they were exposed to. Specifically, in comparison to control plants, insect herbivory increased the amounts of volatile alkanes, aldehydes, and alcohols, and reduced the amounts of esters, benzenoids, and phenylpropanoids. Water shortage reduced the amount of aldehyde volatiles and increased the amount of alcohol volatiles. Moreover, using choice experiments, we found that bumblebees differentiated between stressed and non‐stressed plants based on their volatile compositions, and preferred less stressed ones. Our study indicated that pollinators may use floral volatiles in their foraging decisions and are highly sensitive to variation in the plant conditions. This suggests that volatile cues may create a constraint on the ability of the plants to secure their reproductive success in arid habitats, that are added to the direct stress created by the arid conditions themselves. [ABSTRACT FROM AUTHOR]