References of "Verheggen, François"
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See detailQue faire lors d'invasions de coccinelles asiatiques ?
Verheggen, François ULg; Haubruge, Eric ULg

in Probio-Revue (2010), 33(1), 11-14

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See detailAn introduction device for the aphidophagous hoverfly Episyrphus balteatus (De Geer) (Diptera: Syrphidae)
Leroy, Pascal ULg; Verheggen, François ULg; Capella, Quentin et al

in Biological Control (2010), 54(3), 181-188

Augmentative biocontrol constitutes a safe option to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer ... [more ▼]

Augmentative biocontrol constitutes a safe option to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer) (Diptera: Syrphidae) is a promising candidate for aphid biological control: larvae of this syrphid attack and consume a wide range of aphid species and are found on many vegetable crops. Because natural populations of beneficial insects are not always sufficient to regulate the pest infestations, this work has focused on the conception of a biological control device containing syrphid eggs which ones can easily be introduced in fields or greenhouses. Using semiochemicals [E-(β)-farnesene, R-(+)-limonene and (Z)-3-hexenol], honeydews and “artificial honeydews” (10% or 30% aqueous solutions of sucrose, fructose and glucose), the syrphid oviposition was artificially induced on an inert surface. Specifically, E-(β)-farnesene and concentrated mono-sugars (30%) were identified as the most efficient ovipositional stimulants. To test and validate the biological control device described above, laboratory and field experiments were performed: a plastic lamella covered with syrphid eggs was suspended on aphid infested plants in order to measure the efficiency of the device. The results obtained were promising since populations of 500 aphids were eliminated in ten days when 15 syrphid eggs were introduced. The use of such a biological control device could certainly contribute to the biological control to reduce the aphid infestations. [less ▲]

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See detailThe occurrence of multicolored ladybird, Harmonia axyridis Pallas, a biological control agent in agroecosystems in Wallonia
Vandereycken, Axel ULg; Durieux, Delphine ULg; Haubruge, Eric ULg et al

Conference (2010, May 18)

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations in greenhouses. It took only few years to the insect to get adapted ... [more ▼]

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations in greenhouses. It took only few years to the insect to get adapted to temperate climate conditions and to spread out all over Europe. Now, H. axyridis is one of the coccinellid with the biggest size in Belgium, causing damages to the ecosystems through e.g. intraguild predation (IGP). We are still lacking information about the consequences of the introduction of this superpredator in our agro-ecosystems. This work focuses on the potential impacts of H. axyridis on the entomofauna associated with several crops (potatos, corn, wheat, broad bean). We evaluated in 2009 the occurrence as well as the interactions between aphids and their natural enemies (hoverflies, coccinellids and lacewings) in several agro-ecosystem sites in northern Wallonia. After one year of field observations, were found thirteen coccinellid species, most of the catched individuals being H. axyridis with 64% of the coccinellids, Propylea 14-punctata, 15%, or Coccinella 7-punctata, 14%. This invasive ladybird dominates the group of coccinellids generally in all crops in north Wallonia. The results with the sticky traps show that the maximum occurrence of H. axyridis in crops is observed in chicory, sugar beet and potatoes. The relationship aphid-ladybird in wheat for example, brings out that increase of density of Asian ladybird in mid-July follow the increase of aphids (Sitobion avenae, Sitobion fragariae, Metopolophium dirhodum, Aphis fabae) in the end of June. We also observe that, in most agro-ecosystems, hoverflies and lacewings are the dominant aphid natural enemies. In all crops investigate, the multicolored ladybird occurs with 5% of the aphidophagous after the Chrysopidae, 12% and the Syrphidae, 76%. In 2009, the agro-ecosystems with the most aphidophagous species are carrot and broad bean and these habitats are dominated by hoverflies. [less ▲]

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See detailBiological control using Episyrphus balteatus (De Geer) (Diptera: Syrphidae)
Leroy, Pascal ULg; Verheggen, François ULg; Capella, Quentin et al

Poster (2010, May 18)

Augmentative biocontrol constitutes a safe way to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer ... [more ▼]

Augmentative biocontrol constitutes a safe way to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer) (Diptera: Syrphidae) is a promising candidate for aphid biological control: larvae of this syrphid attack and consume a wide range of aphid species and are found on many vegetable crops. Because natural populations of beneficials are not always sufficient to regulate the pest infestations, this work has focused on the conception of a biological control device containing syrphid eggs which can easily be introduced in fields or greenhouses. Using semiochemicals [E-(β)-farnesene, R-(+)-limonene and (Z)-3-hexenol], honeydews and “artificial honeydews” (10% or 30% aqueous solutions of sucrose, fructose and glucose), the syrphid oviposition was artificially induced on an inert surface. To test and validate the biological control device described above, laboratory and field experiments were performed: a plastic lamella covered with syrphid eggs was suspended on aphid infested plants in order to measure the efficiency of the device. The results obtained were promising since populations of 500 aphids were eliminated in ten days when 15 syrphid eggs were introduced. The use of such a biological control device could certainly contribute to aphid biological control strategies. [less ▲]

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See detailEvolution of Harmonia axyridis (Pallas) alkaloid protection during the year
Fischer, Christophe ULg; Sibret, Virginie; Laurent, Pascal ULg et al

Poster (2010, May 05)

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See detailThe chemical ecology of ladybird beetles
Durieux, Delphine ULg; Verheggen, François ULg; Vandereycken, Axel ULg et al

Conference (2010, May 05)

Ladybird beetles (Coleoptera: Coccinellidae) use a wide variety of semiochemicals to communicate with each other, e.g. finding a mate, protecting themselves from predation or cannibalism, finding a ... [more ▼]

Ladybird beetles (Coleoptera: Coccinellidae) use a wide variety of semiochemicals to communicate with each other, e.g. finding a mate, protecting themselves from predation or cannibalism, finding a shelter to overwinter or ensuring a better survival for their offspring. But chemical communication upon ladybeetles has also found recently to occur with their prey, their prey-host plants and even within their interactions with their natural enemies. Thorough studies on ladybird behaviours towards these compounds could lead to their practical implementation in integrated strategies using ladybirds to control pests, like aphids or mealybugs. [less ▲]

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See detailOccurrence of the multicolored ladybird, Harmonia axyridis PALLAS in Walloon agro-ecosystems
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

Conference (2010, May 05)

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations in greenhouses. It took only few years to the insect to get adapted ... [more ▼]

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations in greenhouses. It took only few years to the insect to get adapted to temperate climate conditions and to spread out all over Europe. Now, H. axyridis is one of the coccinellid with the biggest size in Belgium, causing damages to the ecosystems through e.g. intraguild predation (IGP). We are still lacking information about the consequences of the introduction of this superpredator in our agro-ecosystems. This work focuses on the potential impacts of H. axyridis on the entomofauna associated with several crops (potatos, corn, wheat, broad bean). We evaluated in 2009 the occurrence as well as the interactions between aphids and their natural enemies (hoverflies, coccinellids and lacewings) in several agro-ecosystem sites in northern Wallonia. After one year of field observations, were found thirteen coccinellid species, most of the catched individuals being H. axyridis with 64% of the coccinellids, Propylea 14-punctata, 15%, or Coccinella 7-punctata, 14%. This invasive ladybird dominates the group of coccinellids generally in all crops in north Wallonia. The results with the sticky traps show that the maximum occurrence of H. axyridis in crops is observed in chicory, sugar beet and potatoes. The relationship aphid-ladybird in wheat for example, brings out that increase of density of Asian ladybird in mid-July follow the increase of aphids (Sitobion avenae, Sitobion fragariae, Metopolophium dirhodum, Aphis fabae) in the end of June. We also observe that, in most agro-ecosystems, hoverflies and lacewings are the dominant aphid natural enemies. In all crops investigate, the multicolored ladybird occurs with 5% of the aphidophagous after the Chrysopidae, 12% and the Syrphidae, 76%. In 2009, the agro-ecosystems with the most aphidophagous species are carrot and broad bean and these habitats are dominated by hoverflies. [less ▲]

Detailed reference viewed: 39 (4 ULg)
See detailBiological control device using the aphidophagous hoverfly Episyrphus balteatus (De Geer) (Diptera: Syrphidae)
Leroy, Pascal ULg; Verheggen, François ULg; Francis, Frédéric ULg et al

Poster (2010, May 05)

Augmentative biocontrol constitutes a safe way to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer ... [more ▼]

Augmentative biocontrol constitutes a safe way to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer) (Diptera: Syrphidae) is a promising candidate for aphid biological control: larvae of this syrphid attack and consume a wide range of aphid species and are found on many vegetable crops. Because natural populations of beneficials are not always sufficient to regulate the pest infestations, this work has focused on the conception of a biological control device containing syrphid eggs which can easily be introduced in fields or greenhouses. To test and validate the biological control device described above, laboratory and field experiments were performed: a plastic lamella covered with syrphid eggs was suspended on aphid infested plants in order to measure the efficiency of the device. The results obtained were promising since populations of 500 aphids were eliminated in ten days when 15 syrphid eggs were introduced. The use of such a biological control device could certainly contribute to aphid biological control strategies. [less ▲]

Detailed reference viewed: 56 (6 ULg)
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See detailBiosensors in Forensic Sciences
Frederickx, Christine ULg; Verheggen, François ULg; Haubruge, Eric ULg

Conference (2010, May 05)

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See detailHow do insects communicate with a cadaver?
Dekeirsschieter, Jessica ULg; Verheggen, François ULg; Frederickx, Christine ULg et al

Conference (2010, May 05)

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See detailChemical ecology in forensic entomology
Dekeirsschieter, Jessica ULg; Frederickx, Christine ULg; Verheggen, François ULg et al

Scientific conference (2010, January 07)

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See detailHarmonia axyridis (Pallas) secondary metabolites quantification in relation with aposematism : Part I : Harmonine quantification
Fischer, Christophe ULg; Heuskin, Stéphanie ULg; Laurent, Pascal ULg et al

Poster (2010, January)

These last few years, the multicoloured Asian ladybird, Harmonia axyridis Pallas (Insects: Coleoptera: Coccinellidae), an invasive species, has swiftly spread out in Europe. This aposematic and highly ... [more ▼]

These last few years, the multicoloured Asian ladybird, Harmonia axyridis Pallas (Insects: Coleoptera: Coccinellidae), an invasive species, has swiftly spread out in Europe. This aposematic and highly polymorphic insect is problematic in several ways. It seems to outcompete native coccinellid species; they can group on fruits in vineyards and spoil wine when crushed with grapes; they can aggregate by hundreds in houses to winter. This study aims to investigate the relations between the chemical defences of H. axyridis and warning signals expressed by this bug. To achieve this goal, two original quantification methods of H. axyridis secondary metabolites have been undertaken. The first one allows Fast-GC quantifying harmonine, its main defence alkaloid. The other one permits to determine its emission rate of 2-isopropyl-3-methoxypyrazine, a highly odorous compound probably involved in the communication between individuals and in the aposematism of this insect. This last point will be detailed in another poster. Firstly, a method of extraction, acetylation and purification of harmonine from H. axyridis has been devised to obtain a calibration standard because this molecule is not commercially available. The identity of the extracted compound has been confirmed by mass spectrometry and multidimensional NMR. The GC purity of this N,N-diacetylharmonine is of 100%. During the experiments, its stability in acetone solution at 4°C has been verified. Using this purified molecule, an original method of harmonine quantification has been developed by fast gas chromatography and validated using accuracy profile. The method has been validated for concentrations ranging from 28µg/ml to more than 264µg/ml, with a maximal error risk of 20%. From about 100µg/ml, peaks symmetry decreased, but did not influence the quantification. That accuracy profile validation has been compared with a more classical validation using AOAC (2006) norm, which confirmed the first validation. This method allows quantifying harmonine in one single insect. Harmonine has been quantified in 80 H. axyridis divided into four groups of at least 15 individuals on basis of the morph type and the elytra hue. Males and females harmonine contents did not significantly differ. The mean harmonine content was of 106.6µg/individual with a standard deviation of 80.2µg/individual. The results distribution obtained was not normal and a strong variability between individuals was observed, which explains the high standard deviation. These results and those of the pyrazine and colour analysis have been statistically analyzed in order to show potential correlations between these factors. It would appear that elytra colour is linked with the insect harmonine content. Individuals with a non-melanic orange colour presented harmonine content significantly higher than other studied colours. The harmonine content does not seem linked to the pyrazine emission rate. [less ▲]

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See detailHarmonia axyridis (Pallas) secondary metabolites quantification in relation with aposematism : Part II : Pyrazine quantification
Fischer, Christophe ULg; Heuskin, Stéphanie ULg; Marlet, Christelle ULg et al

Poster (2010, January)

The main objective of this study is to investigate the presence of links between chemical defences and warning signals presented by Harmonia axyridis (Pallas), the multicoloured Asian ladybird (Insects ... [more ▼]

The main objective of this study is to investigate the presence of links between chemical defences and warning signals presented by Harmonia axyridis (Pallas), the multicoloured Asian ladybird (Insects: Coleoptera: Coccinellidae). This second part describes an original quantification method for 2-isopropyl-3-methoxypyrazine (IPMP) by active sampling on thermally desorbed adsorbent (TD) coupled with GC-MS analysis. This highly odorous compound is supposed to be implicated in intra- and interspecific communication. In order to allow harmonine quantification (a defence alkaloid, see Part 1), this method avoid any hemolymph loses by the ladybird (Coccinellids can emit hemolymph when stressed). This method is non-lethal and applicable on one single insect. The quantification method has been validated from 37,5pg to 10 000 pg per adsorbent cartridge. On this range, there is no breakthrough and desorption is complete (>99.4%). At the LOQ (37.5pg/cartridge), the bias is of 20%, but rapidly decreased to less than 5% on the rest of the validated range (100 to 10 000 pg/cartridge). According to AOAC (2006) norm, this method is repeatable but not reproducible. The IPMP emission rate following a stress has been quantified on 80 H. axyridis grouped in four classes on basis of the morph type and the elytra hue. Males and females emission rates did not significantly differ. The mean emission rate is of 707 pg/4h with an extremely high standard deviation of 1766pg/4h due to a great individual variability and a strongly asymmetric distribution of the results. These results and those of the harmonine and colour analysis have been statistically analyzed in order to show potential correlations between these factors. It seems that elytra colour is linked with the insect IPMP emission rate. Individuals with a melanic red colour presented IPMP emission rate significantly lower than other studied colours. The harmonine content does not seem linked to the pyrazine emission rate. [less ▲]

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See detailA fast gas chromatographic method for the study of semiochemical slow release formulations
Heuskin, Stéphanie ULg; Lorge, Stéphanie; Leroy, Pascal ULg et al

Poster (2010, January)

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See detailAphid-ant mutualism: how honeydew sugars influence the behaviour of ant scouts
Detrain, Claire; Verheggen, François ULg; Diez, Lise et al

in Physiological Entomology (2010), 35(2), 168-174

Honeydew is the keystone on which ant-aphid mutualism is built. The present study investigates how each sugar identified in Aphis fabae Scopoli honeydew acts upon the feeding and the laying of a ... [more ▼]

Honeydew is the keystone on which ant-aphid mutualism is built. The present study investigates how each sugar identified in Aphis fabae Scopoli honeydew acts upon the feeding and the laying of a recruitment trail by scouts of the aphid-tending ant Lasius niger Linnaeus, and thus may enhance collective exploitation by the ant mutualists. The feeding preferences shown by L. niger for honeydew sugars are: melezitose = sucrose = raffinose > glucose = fructose > maltose = trehalose = melibiose = xylose. Although feeding is a prerequisite to the launching of trail recruitment, the reverse is not necessarily true: not all ingested sugar solutions elicit a trail-laying behaviour among fed scouts. Trail mark laying is only triggered by raffinose, sucrose or melezitose, with the latter sugar being specific to honeydew. By comparing gustatory and recruitment responses of ant foragers to sugar food sources, the present study clarifies the role of honeydew composition both as a source of energy and as a mediator in ant-aphid interactions. Lasius niger feeding preferences can be related to the physiological suitability of each sugar (i.e. their detection by gustatory receptors as well as their ability to be digested and converted into energy). Regarding recruitment, the aphid-synthesized oligosaccharide (melezitose) could be used by ant scouts as a cue indicative of a long-lasting productive resource that is worthy of collective exploitation and defence against competitors or aphid predators. [less ▲]

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See detailLes phéromones d'alarme dans le règne animal
Verheggen, François ULg; Haubruge, Eric ULg

in Faunistic Entomology - Entomologie Faunistique (2010), 63(4),

Beaucoup d'animaux répondent à la menace de la prédation en produisant des signaux d'alarme qui avertissent les autres individus de la présence de danger ou qui réduisent le succès de prédateurs. Alors ... [more ▼]

Beaucoup d'animaux répondent à la menace de la prédation en produisant des signaux d'alarme qui avertissent les autres individus de la présence de danger ou qui réduisent le succès de prédateurs. Alors que les signaux d'alarme peuvent être de nature visuelle, auditive ou chimique, les phéromones d'alarme sont fréquentes, surtout chez les insectes et les organismes aquatiques. Les plantes aussi émettent des signaux chimiques en réponse à l'attaque par les insectes herbivores qui recrutent les ennemis naturels des ravageurs et qui peuvent induire des mécanismes de défense chez les plantes voisines (ou d'autres parties de la même plante). Dans ce chapitre, nous discutons de notre compréhension actuelle des modes de communications chimiques d’alarme dans les divers groupes d'animaux où ces signaux ont été identifiés (y compris les insectes sociaux et pré-sociaux, les invertébrés marins, les poissons et les mammifères) ainsi que dans le règne végétal. Nous discuterons aussi brièvement l'exploitation des phéromones d'alarme par les ennemis naturels des insectes émettant ces signaux. Nous concluons par une brève discussion de l'exploitation potentielle des signaux d'alarme dans des approches de lutte intégrée contre les espèces nuisibles. [less ▲]

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See detailValidation of a fast gas chromatographic method for the study of semiochemical slow release formulations
Rozet, Eric ULg; Heuskin, Stéphanie ULg; Lorge, Stéphanie et al

in Journal of Pharmaceutical & Biomedical Analysis (2010), 53

The validation of a fast GC-FID analytical method for the quantitative determination of semiochemical sesquiterpenes (E-β-farnesene and β-caryophyllene) to be used in an integrated pest management ... [more ▼]

The validation of a fast GC-FID analytical method for the quantitative determination of semiochemical sesquiterpenes (E-β-farnesene and β-caryophyllene) to be used in an integrated pest management approach is described. Accuracy profiles using total error as decision criteria for validation were used to verify the overall accuracy of the method results within a well defined range of concentrations and to determine the lowest limit of quantification for each analyte. Furthermore it allowed to select a very simple and reliable regression model for calibration curve for the quantification of both analytes as well as to provide measurement uncertainty without any additional experiments. Finally, this validated method was used for the quantification of semiochemicals in slow release formulations. The goal was to verify the protection efficiency of alginate gel beads formulations against oxidation and degradation of sesquiterpenes. The results showed that the alginate beads are adequate slow release devices which protect the bio-active molecules during at least twenty days. [less ▲]

Detailed reference viewed: 99 (26 ULg)