References of "Verheggen, François"
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See detailAttraction of wireworms to root-emitted volatile organic compounds of barley
Barsics, Fanny ULg; Haubruge, Eric ULg; Verheggen, François ULg

Conference (2011, June 20)

The ability of wireworms (Agriotes sordidus Illiger) to orientate towards a blend of volatiles emitted by chopped roots of barley was tested. During individual tests, the larvae chose between the two ... [more ▼]

The ability of wireworms (Agriotes sordidus Illiger) to orientate towards a blend of volatiles emitted by chopped roots of barley was tested. During individual tests, the larvae chose between the two sides of a Y-shaped olfactometer. One side was connected to a chamber containing the chopped roots and the other was connected to an empty chamber. Wireworms chose significantly more often the side of the olfactometer providing the blend of root volatiles. This result underlines the importance of the identification of these compounds and their role assessment alone or combined, as for their effect on wireworms. Such compounds could be used in IPM strategies. [less ▲]

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See detailMicroorganisms from Aphid Honeydew Attract and Enhance the Efficacy of Natural Enemies
Leroy, Pascal ULg; Sabri, Ahmed ULg; Heuskin, Stéphanie ULg et al

in Nature Communications (2011), 2

Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their ... [more ▼]

Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their dispersal in natural environment. Here we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which acts as a kairomone enhancing the efficiency of aphid natural enemies. Our findings represent the first case of a host-associated bacterium driving prey location and ovipositional preference for the natural enemy. We show that this bacterium has a key role in tritrophic interactions because it is the direct source of volatiles used to locate prey. Some specific semiochemicals produced by S. sciuri were also identified as significant attractants and ovipositional stimulants. The use of this host-associated bacterium could certainly provide a novel approach to control aphids in field and greenhouse systems. [less ▲]

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See detailAttraction of wireworms to root-emitted volatile organic compounds of barley
Barsics, Fanny ULg; Haubruge, Eric ULg; Verheggen, François ULg

in Ehlers, Ralf-Udo; Crickmore, Neil; Enkerli, Juerg (Eds.) et al Preceedings of the 13th European Meeting "Biological Control in IPM Systems" : Innsbruck (Austria) 19-23 June 2011 (2011, June)

The ability of wireworms (Agriotes sordidus Illiger) to orientate towards a blend of volatiles emitted by chopped roots of barley was tested. During individual tests, the larvae chose between the two ... [more ▼]

The ability of wireworms (Agriotes sordidus Illiger) to orientate towards a blend of volatiles emitted by chopped roots of barley was tested. During individual tests, the larvae chose between the two sides of a Y-shaped olfactometer. One side was connected to a chamber containing the chopped roots and the other was connected to an empty chamber. Wireworms chose significantly more often the side of the olfactometer providing the blend of root volatiles. This result underlines the importance of the identification of these compounds and their role assessment alone or combined, as for their effect on wireworms. Such compounds could be used in IPM strategies. [less ▲]

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See detailAnt-aphid mutualism - How do ants locate aphid colonies?
Fischer, Christophe ULg; Sablon, Ludovic ULg; Duriaux, Adrien ULg et al

Poster (2011, June)

That some ant species show mutualistic relationships with some aphid species is well known since several decades. Ants protect aphids against natural enemies and as a reward collect the sugar-rich aphid ... [more ▼]

That some ant species show mutualistic relationships with some aphid species is well known since several decades. Ants protect aphids against natural enemies and as a reward collect the sugar-rich aphid excretion called honeydew. However, very little information is available on possible semiochemicals involved in these interactions. This study aims to identify semiochemicals involved in the establishment of this relation, using both chemical and behavioral approaches. Preliminary choice tests confirmed that ant scouts are able to detect aphid colonies at a distance using volatile organic compounds (VOC). Those VOC influencing ant’s orientation may originate from different sources: the attacked plant, the honeydew produced by the aphids and the aphids themselves. VOC emission profiles of each of those potential sources have been established using gas chromatography. Y-olfactometer assay revealed that honeydew volatile compounds are the key element in this distant attraction. Moreover, based on these VOCs, ant scouts are able to discriminate between the honeydew produced by a myrmecophilous and a non myrmecophilous aphid species. Thus, more than just a sugar source, honeydew is an attractant for ant scouts towards myrmecophilous aphids. [less ▲]

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See detailVolatile organic compounds of the roots of barley and their role in the rhizosphere
Fiers, Marie ULg; Barsics, Fanny ULg; Camerman, Marc ULg et al

Poster (2011, May 24)

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates ... [more ▼]

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates. Very few researches have been completed concerning belowground volatiles released into the rhizosphere despite their potential capacity to carry information between organisms. The Rhizovol project, started in autumn 2010, involves 5 different units of Gembloux Agro-Bio Tech collectively studying the production of belowground volatiles by barley roots underlying various biotic interactions in the rhizosphere. Some preliminary results of each partner of the project will be presented. To achieve this goal, analytical methods allowing the sampling, separation, identification and quantification of belowground volatile compounds have to be developed, taking into account their potential modifications in the rhizosphere once released by the roots. They enable the subsequent characterization and study of the interactions between barley and its rhizospheric partners chosen for this study. These interactions imply three types of organisms: beneficial organisms, pathogenic agents and plant and insect pests. Beneficial organisms can promote the growth of barley by the emission of volatiles; on the other hand barley can support their growth and metabolism. These phenomenons will be assessed by the study of 19 strains of plant growth-promoting bacteria (PGPR). Three pathogenic agents - two fungi (Fusarium culmorum and Cochliobolus sativus) and one virus (Barley yellow dwarf virus) - were chosen as they are known to cause various diseases on barley, especially on roots. The attractive or repellent effects of barley root volatiles on the pathogenic agents or their vectors, as well as the effect of volatiles on the diseases evolution will be evaluated. The project also includes several types of pests such as plants and insects. Plants can compete with barley for space and nutrients through volatile interactions. This will be assessed by the study of autotoxicity by barley itself and allelopathy with 8 weeds and a hemiparasitic plant (Rhinanthus minor). The effects of barley volatiles can also impact the severity of the attacks by insects. This part will be conducted with wireworms as they represent worldwide known pests, and aphids, through their viral vector role. Eventually, as soil characteristics can strongly influence the diffusion of volatile compounds, the diffusion behaviour of the identified volatile biomolecules through the soil will be modelled. Tritrophic interactions (e.g. insect-plant-pathogenic fungi) will be studied based on each bitrophic interaction results. Over-all, the Rhizovol project aims at improving the knowledge of interactions mediated by volatile compounds in the rhizosphere and at establishing new biocontrol methods that could contribute to integrated disease and pest management systems. [less ▲]

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See detailImpact of Harmonia axyridis (Coleoptera: Coccinellidae) on the survival rates of other aphidophagous species in semi-field conditions
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

in Communications in Agricultural and Applied Biological Sciences (2011, May 24), 76(2), 219-226

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild ... [more ▼]

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild predator, consuming other aphid natural enemies. Interactions between this exotic ladybird and other aphidophagous species present in Belgian agro-ecosystems such as Coccinella septempunctata, Episyrphus balteatus and Chrysoperla carnea are asymmetric to the benefit of H. axyridis. This study focuses on the survival rate of three aphidophagous species Harmonia axyridis (Ha), Coccinella septempunctata (C7) and Episyrphus balteatus (Eb) placed in cages in biological fields of potato and sugar beet. During June and July, hermetic cages were disposed on the crops with 10 larvae (second stage) of each aphidophagous. Four types of cages were observed (1) Ha+Eb+C7+ aphids, (2) Ha+Eb+C7, (3) Eb+C7+ aphids and (4) Eb+C7. Each combination was repeated three times. In sugar beet fields, E. balteatus was the species with the highest mortality rate. The two coccinellid species had a better survival rate than E. balteatus. All aphidophagous species had higher mortality rates in absence of aphids. In potato, when aphids were present in excess, the survival rates of all aphidophagous insects were lower than in sugar beet probably because A. fabae is less adapted to the potato morphology. Nevertheless, we have observed in potato no mortality of C. 7-punctata during all its development cycle. This suggests that (1) C. 7-punctata may use aphids as food sources more efficiently than H. axyridis and (2) that interactions between aphidophagous could be less frequent (difficulty of mobility). In potato and sugar beet, H. axyridis had the longest development cycle, being still at the larval stage when C. 7-punctata and E. balteatus reached the pupae stage. We can suppose that pupae of E. balteatus and C. 7-punctata were an alternative food (intraguild prey) to H. axyridis when aphids were lacking. Pupae are immobile and therefore more sensitive to the attack of predators. [less ▲]

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See detailField evaluation of survival rates of Harmonia axyridis (Coleoptera: Coccinellidae) and other aphidophagous species
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

Poster (2011, May 24)

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild ... [more ▼]

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild predator, consuming other aphids natural enemies. Interactions between this exotic ladybird and the other aphidophagous species present in Belgian agro-ecosystems such as Coccinella septempunctata, Episyrphus balteatus, Chrysoperla carnea are asymmetric to the benefit of H. axyridis. Many studies have already shown its predatory behaviour. This study focuses on the survival rate of three aphidophagous species Harmonia axyridis (Ha), Coccinella septempunctata (C7) and Episyrphus balteatus (Eb) in biological fields of potato and sugar beet. During June and July, hermetic cages were disposed on the crops with 10 larvae (second stage) of each aphidophagous. There were 4 combinations of insects placed inside the cages (1) Ha+Eb+C7+ aphids, (2) Ha+Eb+C7, (3) Eb+C7+ aphids and (4) Eb+C7. Each combination was repeated three times. Aphids (Aphis fabae) were added in excess when needed. In sugar beet fields, E. balteatus was the species with the highest mortality rate. The two coccinellid species had a better survival rate than E. balteatus. All aphidophagous species had higher mortality rates in absence of aphids. In potato, the survival rate of all aphidophagous was lower than sugar beet when aphids were present in excess probably because A. fabae reproduced less in potato. Nevertheless, we have observed in potato no mortality of C. 7-punctata during all its development cycle. This suggests that C. 7-punctata could use more efficiently aphids as food sources than H. axyridis. In potato and sugar beet, H. axyridis had the longest development cycle, being still at the larval stage when C. 7-punctata and E. balteatus reached the pupae stage. We can suppose that pupae of E. balteatus and C. 7-punctata were an alternative food (intraguild prey) to H. axyridis when aphids were lacking. Pupae are immobile and therefore more sensitive to the attack of predators. [less ▲]

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See detailAttraction of wireworms to root-emitted volatile organic compounds of barley
Barsics, Fanny ULg; Haubruge, Eric ULg; Verheggen, François ULg

Conference (2011, May 24)

Wireworms, the belowground larvae of click beetles (Coleoptera: Elateridae), represent a threat for various crops, including cereals, potatoes and small fruits, in many countries. In order to promote the ... [more ▼]

Wireworms, the belowground larvae of click beetles (Coleoptera: Elateridae), represent a threat for various crops, including cereals, potatoes and small fruits, in many countries. In order to promote the development of bio-pesticides or the selection of resistant varieties, studies concerning the close relationship between wireworms and the roots they attack have to be conducted. Indeed, lacks of knowledge in the chemical ecology of these small but consequent pests baffle such achievements. Here, we studied the reactions of wireworms (Agriotes sordidus Illiger) facing root-emitted volatile organic compounds (VOCs) of barley. We first tested the ability of wireworms to orientate towards a blend of volatile compounds emitted by seven day’s old mashed roots of barley grown in vermiculite. We used a Y-shaped horizontal olfactometre, which inferior half was filled with compressed and humidified vermiculite. Wireworms were able to detect blends of volatiles emitted by mashed roots, and to orientate their foraging behaviour toward the emission source. Volatile compounds were identified from barley roots using SPME-GC-MS and several chemicals were identified. This study is part of a larger programme which purpose is the identification of VOCs emitted by the roots of barley and different actors of the rhizosphere, and to assess their semiochemical functions. [less ▲]

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See detailA semiochemical enhancing the attractiveness of aphidophagous predators in potato crops
Leroy, Pascal ULg; Vandereycken, Axel ULg; Sabri, Ahmed ULg et al

Poster (2011, May 24)

Aphids are major pests of crops worldwide and the use of pesticides has led to resistant populations. The integration of aphid natural enemies in integrated management programs could be an option, but ... [more ▼]

Aphids are major pests of crops worldwide and the use of pesticides has led to resistant populations. The integration of aphid natural enemies in integrated management programs could be an option, but their efficacy is often limited by their quick dispersal from the ecosystem where they are released. Here, using wind-tunnel and field experiments, we have demonstrated that 3-Methyl-2-butenal acts as an efficient attractant and ovipositional stimulant for the hoverfly Episyrphus balteatus (De Geer) (Diptera: Syrphidae), enhancing its efficiency as biological control agent in crop fields. Wind-tunnel assays allowed determining that a minimal dose of 250 µg of 3-Methyl-2-butenal is required to attract the hoverflies over a distance of 2.5 m while a minimal dose of 500 µg is needed to induce the oviposition. Both attraction and oviposition increased proportionally to the tested doses showing that hoverflies are able to regulate their oviposition according to the chemical stimuli from their environment. In field experiments, both Syrphidae and Chrysopidae were strongly attracted by the 3-Methyl-2-butenal at a dose of 10 mg which also induces the oviposition of these two aphid predators in potato crops. This study also highlighted that hoverflies are the most abundant aphid predators found in natural environment. Against aphids, the use of this semiochemical could certainly enhance the efficiency of natural enemies. Furthermore, the use of the chemical cue 3-Methyl-2-butenal could provide a novel approach to control aphids in field and greenhouse systems. [less ▲]

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See detailThe semiochemically mediated interactions between bacteria and insects
Leroy, Pascal ULg; Sabri, Ahmed ULg; Verheggen, François ULg et al

in Chemoecology (2011), 21

In natural environment, semiochemicals are involved in many interactions between the different trophic levels involving insects, plants and hosts for parasitoids or prey for predators. These volatile ... [more ▼]

In natural environment, semiochemicals are involved in many interactions between the different trophic levels involving insects, plants and hosts for parasitoids or prey for predators. These volatile compounds act as messengers within or between insect species, inducing particular behaviours such as the localisation of a source of food, the orientation to an adequate oviposition site, the selection of a suitable breeding site and the localisation of hosts or prey. In this sense, bacteria have been shown to play an important role in the production of volatile compounds which ones act as semiochemicals. This review, focusing on the semiochemically-mediated interactions between bacteria and insects, highlights that bacterial semiochemicals act as important messengers for insects. Indeed, in most of the studies reported here, insects respond to specific volatiles emitted by specific bacteria hosted by the insect itself (gut, mouthparts, etc.) or present in the natural environment where the insect evolves. Particularly, bacteria from the families Enterobacteriaceae, Pseudomonaceae and Bacillaceae are involved in many interactions with insects. Because semiochemicals naturally produced by bacteria could be a very interesting option for pest management, advances in this field are discussed in the context of biological control against insect pests. [less ▲]

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See detailInsectes et communication chimique - Techniques et méthodes en écologie chimique
Verheggen, François ULg

Conference (2011, March 17)

Les insectes communiquent avec leurs semblables et avec leur environnement par le biais de molécules organiques informatives nommées sémiochimiques. L'écologie chimique est la branche de l'écologie qui s ... [more ▼]

Les insectes communiquent avec leurs semblables et avec leur environnement par le biais de molécules organiques informatives nommées sémiochimiques. L'écologie chimique est la branche de l'écologie qui s'intéresse au décriptage de ce mode de communication, dont le maitre d'œuvre est le système olfactif des insectes, où antennes et sensilles supportent toute la machinerie physiologique nécessaire à la perception des phéromones et coactones. Pour comprendre le language chimique employé par un insecte, de nombreux outils ont été développés, permettant (1) l'échantillonnage des molécules organiques produites par un insecte, (2) la séparation, la quantification et l'identification des différents constituants du mélange phéromonal,(3) l'étude de la perception par le système olfactif de l'insecte et (4) l'étude du comportement d'un individu mis en présence d'un potentiel bouquet phéromonal ou de l'un de ses constituants. De nombreuses phéromones et coactones ont déjà trouvé le chemin de la valorisation dans le domaine de la protection des cultures. Bien que les insectes d'intérêt agronomique soient les plus largement étudiés, les sémiochimiques employés par d'autres groupes d'insectes font l'objet de nouvelles recherches, avec notamment l'émergence de l'entomologie criminelle [less ▲]

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See detailInsectes et communication chimique - Sémiochimiques et olfaction
Verheggen, François ULg

Conference (2011, March 15)

Les insectes communiquent avec leurs semblables et avec leur environnement par le biais de molécules organiques informatives nommées sémiochimiques. L'écologie chimique est la branche de l'écologie qui s ... [more ▼]

Les insectes communiquent avec leurs semblables et avec leur environnement par le biais de molécules organiques informatives nommées sémiochimiques. L'écologie chimique est la branche de l'écologie qui s'intéresse au décriptage de ce mode de communication, dont le maitre d'œuvre est le système olfactif des insectes, où antennes et sensilles supportent toute la machinerie physiologique nécessaire à la perception des phéromones et coactones. Pour comprendre le language chimique employé par un insecte, de nombreux outils ont été développés, permettant (1) l'échantillonnage des molécules organiques produites par un insecte, (2) la séparation, la quantification et l'identification des différents constituants du mélange phéromonal,(3) l'étude de la perception par le système olfactif de l'insecte et (4) l'étude du comportement d'un individu mis en présence d'un potentiel bouquet phéromonal ou de l'un de ses constituants. De nombreuses phéromones et coactones ont déjà trouvé le chemin de la valorisation dans le domaine de la protection des cultures. Bien que les insectes d'intérêt agronomique soient les plus largement étudiés, les sémiochimiques employés par d'autres groupes d'insectes font l'objet de nouvelles recherches, avec notamment l'émergence de l'entomologie criminelle [less ▲]

Detailed reference viewed: 74 (9 ULg)