References of "Verheggen, François"
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See detailEntandrophragma cylindricum (Sprague) Sprague (Meliaceae), une espèce ligneuse concurrentielle en Afrique centrale (synthèse bibliographique)
Tabi Eckebil, Paule ULg; Verheggen, François ULg; Doucet, Jean-Louis ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment (2017), 21(1), 80-97

Introduction. De nos jours, la gestion des ressources forestières ne se focalise plus sur l’exploitation exclusive du bois d’oeuvre, mais prend également en considération les produits forestiers non ... [more ▼]

Introduction. De nos jours, la gestion des ressources forestières ne se focalise plus sur l’exploitation exclusive du bois d’oeuvre, mais prend également en considération les produits forestiers non ligneux. Entandrophragma cylindricum (Sprague) Sprague, de son nom commercial « sapelli/sapele », de la famille des Meliaceae, illustre parfaitement cette situation. Le présent article fait un état de l’art des connaissances concernant E. cylindricum et présente quelques informations sur la chenille qui lui est inféodée. Littérature. Le sapelli est une des espèces ligneuses les plus exploitées d’Afrique centrale pour son bois d’oeuvre. Il est répandu dans la forêt dense humide semi-caducifoliée du domaine guinéo-congolais. C’est une espèce semi-héliophile, son mode de dispersion est anémochore et sa phénologie est régulière. Selon la sylviculture appliquée, sa croissance en diamètre peut atteindre jusque 0,82 cm par an. Cette essence est également l’hôte d’une espèce de chenille comestible riche en protéines, I. oyemensis Rougeot. Fortement appréciée par les populations locales, cette chenille fait également l’objet d’un commerce régional et international. Enfin, l’écorce du sapelli est reconnue pour son intérêt ethnobotanique, particulièrement en médecine traditionnelle. Conclusions. Les informations tirées de la littérature ont permis de mettre en évidence certaines lacunes relatives à l’écologie et au mode de reproduction de cette espèce et, ceci, en dépit de son importance pour le commerce du bois. De plus, les inconnues quant à la productivité et la saisonnalité des chenilles d’Imbrasia oyemensis sur cet arbre nécessitent de développer des recherches complémentaires pour garantir la durabilité de l’exploitation simultanée de la ressource ligneuse et non ligneuse et pour proposer des modes de gestion concertés entre exploitants industriels et populations locales. [less ▲]

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See detailEntomologie forensique: les insectes résolvent les crimes
Verheggen, François ULg

Scientific conference (2017, February 02)

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See detailStructure and distribution of the sensilla on the antennae of Tuta absoluta (Lepidoptera: Gelechiidae)
Bawin, Thomas ULg; Collard, France ULg; De Backer, Lara ULg et al

in Micron (2017), 96

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread devastating pest that develops on tomato and other economically important solanaceous crops. Current semiochemically-based ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread devastating pest that develops on tomato and other economically important solanaceous crops. Current semiochemically-based management strategies still fail to significantly reduce damages and need to be improved. Here we describe under scanning and transmission electron microscopy the structure and distribution of the sensilla that are displayed on adult antennae. These were similar in size between males (3424.4 ± 135.3 μm) and females (3292.1 ± 111.5 μm), being segmented into a scape, a pedicel, and a distal filiform flagellum. Eight morphological sensilla types were observed on both sexes: Böhm’s bristles, sensilla squamiformia, sensilla trichodea, sensilla basiconica (two subtypes), sensilla chaetica, sensilla coeloconica, sensilla auricillica, and sensilla styloconica. The main sexual dimorphism was related to the higher abundance of sensilla trichodea in males, twice as abundant as in females. The putative functional significance of the different sensilla types regarding the insect ecology is discussed based on the available literature. This work provides descriptions of the antennae and related sensory structures. We expect these results to help develop further electrophysiological investigations aiming to a better understanding of T. absoluta olfaction. [less ▲]

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See detailElevated carbon dioxide concentration reduces alarm signaling in aphids
Boullis, Antoine ULg; Fassotte, Bérénice ULg; Sarles, Landry ULg et al

in Journal of Chemical Ecology (2017), 43

Insects often rely on olfaction to communicate with surrounding conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in ... [more ▼]

Insects often rely on olfaction to communicate with surrounding conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in atmospheric greenhouse gas concentrations will impact pheromonal communication by insects. Here, we hypothesize that changes in the concentration of atmospheric carbon dioxide (CO2) affect the whole dynamics of alarm signaling in aphids, including: (1) the production of the active compound (E)-β-farnesene (Eβf), (2) emission behavior when under attack, (3) perception by the olfactory apparatus, and (4) the escape response. We reared two strains of the pea aphid Acyrthosiphon pisum under ambient and elevated CO2 concentrations for several generations. We found that an increase in CO2 concentration reduced the production (i.e., individual content) and emission of Eβf (released under predation events). While no difference in Eβf neuronal perception was observed, we found that an increase in CO2 strongly reduces the escape behavior expressed by an aphid colony following exposure to natural doses of the alarm pheromone. In conclusion, our results confirm that changes to greenhouse gases do impact chemical communication in insects, and could potentially have a cascade effect on interactions with higher trophic levels. [less ▲]

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See detailIdentification of walnut husk (Juglans regia L.) volatiles and the behavioural response of the invasiveWalnut Husk Fly, Rhagoletis completa Cresson
Sarles, Landry ULg; Boullis, Antoine ULg; Fassotte, Bérénice ULg et al

in Pest Management Science (2017)

Abstract BACKGROUND: Several European countries are important walnut (Juglans regia L.) producers. However, these countries must contendwith the recent introduction of theWalnut Husk Fly,Rhagoletis ... [more ▼]

Abstract BACKGROUND: Several European countries are important walnut (Juglans regia L.) producers. However, these countries must contendwith the recent introduction of theWalnut Husk Fly,Rhagoletis completa Cresson (Diptera, Tephritidae),which is causing severe economic losses, especially in organic production. Because most Tephritid fruit flies use kairomones in their search for host plants, we hypothesise that this highly specialist species orients toward the volatile blend released by walnut husks. RESULTS:We collected, identified, and quantified the volatile organic chemicals (VOCs) released by walnut husks from themost commonly cultivated variety in France (Franquette). Then, the behavioural response of R. completa toward synthetic odour blends was recorded in dual choice assays conducted in net cages. A total of 26 VOCs were identified, with 𝜶-pinene, 𝜷-pinene, trans-linalool, eugenol, and tetradecane representing the major constituents. In the dual choice assay, male and female R. completa were strongly attracted to synthetic blend that includedmost of the identified husk VOCs. CONCLUSION:When searching for a host plant, R. completa use host fruit kairomones. The potential of these semiochemicals in monitoring andmanagement of this quarantine pest is discussed. [less ▲]

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See detailWalnut husk fly, Rhagoletis completa (Diptera: Tephritidae), invades Europe: invasion potential and control strategies
Verheggen, François ULg; Verhaeghe, Agnès; Giordanengo, Philippe et al

in Applied Entomology and Zoology (2017), 52(1), 1-7

Rhagoletis completa Cresson (Diptera: Tephritidae) is native to North America and invaded Western Europe in the late 1980s, causing important damage to its principal host, walnut (Juglans spp.). In this ... [more ▼]

Rhagoletis completa Cresson (Diptera: Tephritidae) is native to North America and invaded Western Europe in the late 1980s, causing important damage to its principal host, walnut (Juglans spp.). In this review, we summarize the important elements of R. completa’s biology, phytosanitary status and methods used in Europe for its control, and then present the main conclusions associated with a completed risk analysis performed in 2014 to evaluate the dispersion and establishment potential of R. completa in Europe. The walnut husk fly was initially identified in Switzerland (1988) and Italy (1991), from where it spread to at least seven additional countries: France, Spain, Germany, Austria, Croatia, Slovenia and Hungary. R. completa has not reached the limits of its potential distribution. The main dissemination pathways within Europe include: (1) natural adult dissemination; (2) adult hitchhiker behaviour; and, to a lesser extent, (3) transportation of larvae in fresh fruits. R. completa host plants are widely distributed in Europe, either as isolated wild trees or in orchards, favouring the probability of fly establishment in currently fly-free areas. In addition, the European territories where Juglans species are present share biogeographic similarities. In orchards where R. completa is present and uncontrolled, 100% of walnut trees can be infested, causing losses in walnut yields of up to 80%. The negative effect is low (<10% yield loss) under phytosanitary control, although additional costs must also be considered to support specific monitoring for R. completa. The information presented here underlines a strong need for better walnut husk fly monitoring across European countries, as well as for increasing efforts to develop biological methods to control this emerging pest. [less ▲]

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See detailInsects complex associated with the tropical basil, Ocimum gratissimum L. (Lamiaceae) in southern Benin.
Yarou, Boni Barthélémy ULg; Bokonon-Ganta, H. Aimé; Assogba Komlan, Françoise et al

Poster (2016, December 16)

Tropical basil is an aromatic leafy vegetable used for its medicinal and therapeutic properties in numerous countries in West Africa (Benin, Nigeria, Togo, etc.). In Benin, it is produced on almost all ... [more ▼]

Tropical basil is an aromatic leafy vegetable used for its medicinal and therapeutic properties in numerous countries in West Africa (Benin, Nigeria, Togo, etc.). In Benin, it is produced on almost all urban and periurban garden throughout the year for fresh market. Until now there are few or nearly no publications about the arthropod community of this specie, even less in the context of Benin. Thus, to assess this community, basil plots were mowed using a sweep net in three localities (Ouidah, Togba and Sèmè) of southern Benin. Preliminary results focus on the different insect families that colonized tropical basil in southern Benin environmental conditions. These include: Aphididae (Homoptera), Cercopidae (Homoptera), Chrysomelidae (Coleoptera), Coccinelledidea (Coleoptera), Meloidae (Coleoptera), Braconidae (Hymenoptera), Ichneumonidae (Hymenoptera), Formicidae (Hymenoptera), Vespidae (Hymenoptera), Apoidae (Hymenoptera), Reduviidae (Heteroptera), Pentatomidae (Heteroptera), Pyrgomorphidae (Orthoptera), Acrididae (Orthoptera), Syrphidae (Diptera), Diopsidae (Diptera). Among these families, there are pests: Aphis gossypii G. (Homoptera: Aphididae), Zonocerus variegatus L. (Orthoptera: Pyrgomorphidae), etc.; predators: Ischiodon aegyptius W. (Diptera: Syrphidae), Cheilomenes spp. (Coleoptera: Coccinelledidea), Rhynocoris spp. (Heteroptera: Reduviidae), etc.; parasitoids and pollinators. From this study, it appeared that there is a large diversity of families and functional groups (pests, predators, parasitoids and pollinators) associated with tropical basil . Moreover, the presence of natural enemies could be an advantage for farmers in intercropping systems. This would help reduce the use of synthetic insecticides. This result, which is a first knowledge of the insect fauna associated with tropical basil under the environmental conditions of Southern Benin, will be supplemented by a spatio temporal study to assess the variability and the dynamics of this insect fauna. [less ▲]

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See detailTuta absoluta (Lepidoptera: Gelechiidae) ability to develop on potato tubers
Bawin, Thomas ULg; De Backer, Lara ULg; Yarou, Boni Barthélémy ULg et al

Poster (2016, December 16)

Tuta absoluta (Lepidoptera: Gelechiidae) is a widespread pest that threatens commercial production of solanaceous crops. Larvae feed on the mesophyll of all aerial parts of the plants resulting in ... [more ▼]

Tuta absoluta (Lepidoptera: Gelechiidae) is a widespread pest that threatens commercial production of solanaceous crops. Larvae feed on the mesophyll of all aerial parts of the plants resulting in significant yield losses and cosmetic damages.It is classically assumed that underground plant parts are not affected but larval development on potato tubers has recently been suspected. However, this assumption is poorly supported in the literature. Potato tubers might represent an unsuspected mean of persistence and dispersal in agricultural environments.Oviposition tests were here conducted using dormant and active (sprouts less than 5 cm) potato tubers in net cages. Oviposition only occurred on the sprouts of active tubers, supporting larval growth until adult emergency. Tuber dissection revealed burrows starting from sprouts inside the flesh. Additional fitness assays were conducted on non-sprouted tubers and revealed that first instar larvae were able to enter the skin and create burrows, living inside and feeding on potato flesh, although none of them survived. [less ▲]

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See detailOviposition deterring effect of Ocimum basilicum L. (Lamiaceae) on Tuta absoluta Meyrick (Lepidoptera: Gelechiidae)
Yarou, Boni Barthélémy ULg; Bawin, Thomas ULg; Boullis, Antoine ULg et al

Poster (2016, December 02)

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yield in greenhouses and fields, in several countries around the world. Because synthetic ... [more ▼]

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yield in greenhouses and fields, in several countries around the world. Because synthetic insecticides lead to resistance and have adverse effects on natural enemies and producers’ health, there is a need for alternatives. In this study, we assess the oviposition deterring effect of O. basilicum using dual-choice behavioral assays performed in flight tunnels. Two modalities were tested, i.e. (1) a tomato plant associated either with an O. basilicum plant versus a tomato plant associated with a plastic pot only filled with potting soil, and (2) a tomato plant with basil essential oil (EO) formulated in paraffin oil (PO) versus a tomato plant with PO only. A 1 ml cylindrical polyethylene plug loaded with 100 µl of solution (formulated EO or PO) was placed on each plant as a diffuser. Forty-eight hours after the release of unsexed adult individuals randomly sampled from the rearing in the central area of the tunnel, we found that plants and EOs reduced T. absoluta oviposition behavior on a nearby located tomato plant. GC-MS analyses showed that the major constituents include estragol (73.8%), linalool (8.6%), β-elemene (2.9%) in O. basilicum essential oils and E-α-bergamotene (38.9%), methyl eugenol (26.1 %), E-β-ocimene (17.7 % ) in O. basilicum VOCs collected with solid-phase micro-extraction method. These results suggest a valuable potential of O. basilicum and associated essential oils as component of an integrated management strategy against the tomato leafminer. [less ▲]

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See detailEffectiveness of pheromone traps against Tuta absoluta
Ettaib, Refki; Belkadhi Mohamed, Sadok; Ben Belgacem, Ali et al

in Journal of Entomology and Zoology Studies (2016), 4(6)

In the Tunisian south, the heated greenhouses are an important axis of development of agriculture thanks to the big geothermal potential of this zone. Currently, this sector suffers from several ... [more ▼]

In the Tunisian south, the heated greenhouses are an important axis of development of agriculture thanks to the big geothermal potential of this zone. Currently, this sector suffers from several phytosanitary problems. In the last years, a new insect, Tuta absoluta, threaten the cultures of cultivated tomatoes in heated greenhouses. To improve control of T. absoluta, the effectiveness of pheromone traps (associated or not with a source of light) and luminous traps (associated or not with water, with limed buckets for limed covers) were compared. The results show that the traps with pheromones significantly catch more adults of T. absoluta compared to all the other types of traps (average number of trapped adults of T. absoluta = 73.4 (± 142)). The luminous traps associated with water, with limed buckets as with limed covers show, as for them, an intermediate effectiveness. In spite of this slightly less effectiveness, the luminous traps have the advantage of low costs of production as well as the advantage of simultaneously capturing males and females of T. absoluta. [less ▲]

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See detailComportement du puceron du pois face aux volatiles du basilic.
Yarou, Boni Barthélémy ULg; Boullis, Antoine ULg; Verheggen, François ULg et al

Poster (2016, October 22)

Les pucerons font partie des insectes qui causent des dégâts d’importances économiques sur une grande diversité de plantes cultivées. Les insecticides de synthèse généralement utilisés pour les contrôler ... [more ▼]

Les pucerons font partie des insectes qui causent des dégâts d’importances économiques sur une grande diversité de plantes cultivées. Les insecticides de synthèse généralement utilisés pour les contrôler montrent de plus en plus leurs limites (résistance), et sont néfastes pour l’homme et l’environnement. Dans la recherche de méthodes de lutte alternatives, le comportement de choix d’Acyrthosiphon pisum Harris (Homoptera : Aphididae) exposé à des sources d’odeurs de plant de fèves (Vicia fabae L.) et du basilic européen (Ocimum basilicum L.) à l’aide d’un olfactomètre en Y a été étudié. Les observations de cette expérience montrent que les pucerons se dirigent préférentiellement vers la source d’odeurs de fève et y passent plus de temps. Ce résultat montre que les volatiles du basilic ont un effet répulsif sur les pucerons du pois. D’autres tests seront évalués sur des espèces de pucerons plutôt généralistes afin de valider l’effet répulsif du basilic sur les pucerons. [less ▲]

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See detailSemiochemicals to control wireworms
Verheggen, François ULg

Conference (2016, October 12)

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See detailStudy of the volatile organic compounds in the interaction between banana plants and the fungal disease Fusarium oxysporum f.sp. cubense Tropical Race 4 (FocTR4)
Berhal, Chadi ULg; De Clerck, Caroline ULg; LEVICEK, CAROLINA et al

Conference (2016, October 11)

Banana fruit (Musa sp.) ranks fourth in term of worldwide production, and has economical and nutritional key values. Cavendish is the popular and most dominant variety of the dessert banana group ... [more ▼]

Banana fruit (Musa sp.) ranks fourth in term of worldwide production, and has economical and nutritional key values. Cavendish is the popular and most dominant variety of the dessert banana group. Nowadays, it is endangered by the emergent race of the Panama disease, caused by Fusarium oxysporum f.sp. cubense TR4 (Foc TR4). Despite the importance of the Volatile Organic Compounds (VOCs), which are secondary metabolites with a high vapour pressure, and their role in plant protection, they have never been documented as a way to manage this disease on Cavendish. Thus, the aim of this PhD thesis is to study the VOCs in the specific interaction Cavendish/Foc TR4, as a way to manage this threat. Based on the work previously done with other plants at Gembloux Agro-Bio Tech, a protocol was optimized for the extraction of the banana plant’s VOCs. In parallel, models of in-vitro and in-vivo inoculations are under development to distinguish the VOCs emitted by the root zone and those emitted by the aerial part of the plant. The results of the first analysis showed that the majority of the Cavendish VOCs belongs to the terpenes group, as well as ketones and an organic ester. The VOCs specifically emitted during the plant-pathogen interaction will be studied more in depth by evaluating their effect on the plant and the pathogen. At long term, and depending on the results, agro-ecological applications of this knowledge could include breeding for new variety or combining banana with other plants expressing VOCs against Foc TR4, applying VOCs on field to stimulate plant defences or to contain the pathogen. [less ▲]

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See detailDevelopment of a semiochemical-based control method against the walnut husk fly, Rhagoletis completa Cresson
Sarles, Landry ULg; Lognay, Georges ULg; Verhaeghe, Agnès et al

Poster (2016, September 15)

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See detailWill climate change affect insect pheromonal communication?
Boullis, Antoine ULg; Detrain, Claire; Francis, Frédéric ULg et al

in Current Opinion in Insect Science (2016)

Understanding how climate change will affect species interactions is a challenge for all branches of ecology. We have only limited understanding of how increasing temperature and atmospheric CO2 and O3 ... [more ▼]

Understanding how climate change will affect species interactions is a challenge for all branches of ecology. We have only limited understanding of how increasing temperature and atmospheric CO2 and O3 levels will affect pheromone-mediated communication among insects. Based on the existing literature, we suggest that the entire process of pheromonal communication, from production to behavioural response, is likely to be impacted by increases in temperature and modifications to atmospheric CO2 and O3 levels. We argue that insect species relying on long-range chemical signals will be most impacted, because these signals will likely suffer from longer exposure to oxidative gases during dispersal. We provide future directions for research programmes investigating the consequences of climate change on insect pheromonal communication. [less ▲]

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See detailAbility of Tuta absoluta (Lepidoptera: Gelechiidae) to develop on alternative host plant species
Bawin, Thomas ULg; Dujeu, David; De Backer, Lara ULg et al

in Canadian Entomologist (2016), 148(4), 434-442

The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous crops. The characterization of its host ... [more ▼]

The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous crops. The characterization of its host range could help to understand and prevent the dispersion behavior of the insect in the environment. In this study, the ability of T. absoluta to develop on 12 cultivated or non-cultivated plants including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae and Malvaceae species under laboratory conditions was assessed. For each plant species, we monitored the development times of immature stages, survival, sex ratios and adult fecundity rates. All the 6 tested non-solanaceous plants, including Chenopodium, Convolvulus and Malva species, were not able to sustain (i.e. allow growth and development) T. absoluta larvae. Among Solanaceae, Solanum species were the most suitable host plants for the pest, but others could be opportunistically colonized with fewer incidences. T. absoluta appears to be strongly related to solanaceous plants which would predominantly support self-sustaining field populations. Preventing crop infestation by removing potential host plants in the immediate field vicinity and culture rotations with non-solanaceous crops is of primary importance. [less ▲]

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See detailMicroorganisms and semiochemicals to manipulate aphidophagous predators
Verheggen, François ULg

Conference (2016, August)

Semiochemicals provide a powerful way for organisms to communicate and coordinate their behaviors. But they also represent opportunities for other organisms to intercept and exploit such signals. There ... [more ▼]

Semiochemicals provide a powerful way for organisms to communicate and coordinate their behaviors. But they also represent opportunities for other organisms to intercept and exploit such signals. There are now numerous examples of natural enemies eavesdropping the intraspecific communication of their prey to better locate them. Aphid natural enemies, including predators and parasitoids, frequently exhibit innate responses to chemical cues reliably associated with aphids, and there is also abundant evidence that learning of profitable chemical cues frequently occurs. Thenceforth, the efficiency of aphid natural enemies to locate their prey is mainly based on their ability to perceive and orientate toward aphid-associated semiochemicals. Aphid predators were shown to respond to different groups of aphid-related semiochemicals, including aphid-induced plant volatiles; aphid pheromones and the more recently identified bacteria-produced honeydew volatiles. These laboratory studies suggest potentially promising avenues for the deployment of aphid-associated semiochemicals for the management of these pest species. While laboratory experiments are invaluable tools for revealing mechanisms, additional field studies are however needed to test ecological relevance of the observed effects. Although it is now possible to attract naturally occurring aphid predators in a crop field using semiochemicals, future work should more fully explore the broader ecological context in which signaling occurs. The information gained from a deeper understanding of the chemical ecology of aphid-natural enemy interaction will enhance our understanding of the chemical biology and ecology of aphids, and may facilitate the design of novel control strategies. [less ▲]

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