References of "Francis, Frédéric"
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See detailDevelopment of entomopathogenic fungi in mosquito control: which kind of production for which efficiency?
Bawin, Thomas ULg; Delvigne, Frank ULg; Francis, Frédéric ULg

Poster (2014, August 06)

Mosquitoes (Diptera: Culicidae) are zoonotic vectors responsible for numerous infectious diseases of medical and veterinary importance such as filariasis, malaria and encephalitis. As part of an ... [more ▼]

Mosquitoes (Diptera: Culicidae) are zoonotic vectors responsible for numerous infectious diseases of medical and veterinary importance such as filariasis, malaria and encephalitis. As part of an integrated vector control, entomopathogenic fungi could be developed as biopesticides in two ways: spores and metabolites recognized as effective virulence factors. Solid-state fermentation enhances spore production and induces the secretion of metabolites quantitatively and qualitatively different from submerged fermentation, which impairs fungal metabolic efficiency. In this context, we showed high spore productivity of solid-state media based on agro-industrial substrates as wheat bran. Spores remained pathogenic, as revealed by classical toxicity tests and electron microscopy. However, the absence of free water makes culture parameter variations difficult to control in large-scale. Recently, we performed a bioreactor design intended for simultaneous spore and metabolite production, combining the technological advantages of submerged and solid-state fermentations. Biofilm fermentation (i.e. growth of fungal biomass on an inert support immerged in a nutrient medium) is a tremendous production system favouring the secretion of insecticidal metabolites in the liquid medium as we showed recently. This is also an interesting tool to provide an overview of the complexity of the metabolic pathways involved in the regulation of extracellular metabolites secretion because corresponding genes are reported to be differentially expressed from classical fermentation systems. Researches in vector control are currently intensified. In this context, the identification of genes and metabolites specifically expressed during biofilm fermentation will help to develop new technologies related both to the design of bioreactor and the production of insecticidal proteins. [less ▲]

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See detailCrop association to improve aphid biological control
Chevalier Mendes Lopes, Thomas ULg; Bosquée, Emilie ULg; Bodson, Bernard ULg et al

Poster (2014, August)

This research focused on the development of sustainable alternative methods to control aphids, giving special emphasis on cultural practices and plant management systems. Increasing the diversity within ... [more ▼]

This research focused on the development of sustainable alternative methods to control aphids, giving special emphasis on cultural practices and plant management systems. Increasing the diversity within crops may have several beneficial effects on pest control, creating attractive habitats for indigenous beneficial fauna and simultaneously deterring pests (“push-pull” approach). In this field study, two wheat/pea associations (mixed cropping and strip cropping) where compared to monocultures of pea and wheat. The abundance and diversity of adult aphidophagous beneficials (predators and parasitoids) were accessed weekly, using yellow traps, while aphids were observed directly on plants. All individuals were identified down to the level of species. In both crops, the percentage of aphid infestation and density of colonies were significantly higher in monocultures during the abundance periods. The mixing was particularly beneficial for the pea, while strip cropping was more efficient for the wheat. Concerning beneficials, their abundance was also significantly higher in monocultures, comparing with the other treatments. This study shows that increasing diversity within crops can prevent them from aphid infestations. However, additional methods are needed to attract more efficiently the aphidophagous beneficials, in order to promote the natural control of aphids. [less ▲]

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See detailImpacts d’une association culturale de pois et de pommes de terre sur les pucerons et auxiliaires aphidiphages en Chine
Bosquée, Emilie ULg; Chevalier Mendes Lopes, Thomas ULg; Serteyn, Laurent et al

in Entomologie Faunistique = Faunistic Entomology (2014), 67

Crop associations can have beneficial effects on the control of insect pests. This study was conducted in the Shandong province (China) to assess the impact of potatoes and peas association on the ... [more ▼]

Crop associations can have beneficial effects on the control of insect pests. This study was conducted in the Shandong province (China) to assess the impact of potatoes and peas association on the populations of aphids and their natural enemies. Observations on potato plants and trapping (yellow pan traps) were performed. During the season, the degree of infestation didn’t differ significantly between the association and the pure stand. However, one week after the aphids abundance peak, predators and parasitoid mummies were significantly more abundant in the association compared with the pure stand. Trapping give a more general idea about the richness and diversity of adult natural enemies present in the environment. The parasitoid specie Aphidius gifuensis (Ashmead) was the most abundant among beneficials. Propylea japonica (Thunberg) and Harmonia axyridis (Pallas) were prevalent among predators. Few hoverflies and lacewings were trapped. This study contributes to better evaluate the potential of crop associations as an alternative method to control aphids without insecticides in this region. [less ▲]

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See detailIdentification and comparison of proteome patterns of English Grain Aphids on resistant and susceptible wheat
Bosquée, Emilie ULg; Barrios San Martin, Joceline; C. RAMÍREZ, Claudio et al

Poster (2014, August)

Some varieties of wheat are resistant to some aphid clones of the English Grain Aphid (Sitobion avenae). This study used 2D-DIGE coupled with protein identification by Maldi-Tof-MS to compare the proteome ... [more ▼]

Some varieties of wheat are resistant to some aphid clones of the English Grain Aphid (Sitobion avenae). This study used 2D-DIGE coupled with protein identification by Maldi-Tof-MS to compare the proteome patterns of English Grain Aphids on resistant (Llareta) and susceptible (Huayún) wheat lines. Aphids were exposed to wheat during 2 weeks (short term: ST) and 4 weeks (long term: LT). Four treatments were compared: Llareta-ST, Llareta-LT, Huayún-ST, Huayún-LT. Experiment was conducted using different Sitobion avenae clones whose symbionts were previously characterized. Results showed that aphids had low performance on resistant plants. Seventy-two protein spots showed significant quantitative differences among the four treatment groups. Proteomic approach will allow a better understanding of interaction mechanisms between aphids and wheat. [less ▲]

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See detailAphid - symbiont interactions : multitrophic "omic" approaches to investigate multitrophic interactions
Bosquée, Emilie ULg; Bauwens, Julien ULg; Mazzucchelli, Gabriel ULg et al

Poster (2014, August)

« Omics » found recent developments due to significant improvement and availability of both separation and identification methods. For proteomics, functional information’s linked to the studied proteins ... [more ▼]

« Omics » found recent developments due to significant improvement and availability of both separation and identification methods. For proteomics, functional information’s linked to the studied proteins was brought when compared to genomic approach. For these reasons, a panel of tools is available to determine the proteome patterns related to differential adaptation of insects to cope with plant defence mechanisms or to transmit virus. The adaptation and metabolic changes of aphids in relation to host plants focusing on the role of the bacterial endosymbionts was investigated. Use of artificial diet including diverse antibiotics but also the comparison of proteomes related to whole aphid and respective purified bacterial symbionts were studied to identify the respective origin and function of proteins constituting the studied proteomes. Diverse methods including 2D-DIGE, liquid chromatography coupled with mass spectrometry and data bank investigations were developed. From the proteome investigation, characterisation of good and bad virus vectors was also performed in different aphid - plant - virus models. Particular proteins of interest were selected. This broad proteomic approach will be discussed as an interesting and reliable tool to study the biologically involved proteins from aphids in response to several environmental changes [less ▲]

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See detailIdentification of lectins as virus competitors in aphid vectors: from fundamental to applied approaches
Bosquée, Emilie ULg; Chen, Ju Lian; Yong, Liu et al

Poster (2014, August)

Aphids remain difficult virus vectors to be controlled in many crops. Within this context of biological control against aphids and investigation on virus transmission (both non persistent Potato virus Y ... [more ▼]

Aphids remain difficult virus vectors to be controlled in many crops. Within this context of biological control against aphids and investigation on virus transmission (both non persistent Potato virus Y (PVY) and Cucumber Mosaic Virus (CMV) and persistent Barley Yellow Dwarf Virus, the use of lectins was developed. Indeed, the effects of lectin binding to glycoprotein aphid receptors on virus transmission were tested in laboratory via the use of artificial diets using different virus models. Differential effects on virus transmission efficiency were determined. By example, a strong interference between GNA and PVY was observed. In consequence, the lectin was considered as promising proteins and could be potential competitors to virus. For further research, a fast protein liquid chromatography was performed to identify aphid proteins related to binding to efficient lectin competitors. Moreover, to detect involved proteins in aphids, two-dimensional gel electrophoresis approach coupled to mass spectrometry was developped to identify the glycosylated proteins determining virus transmission efficiency. Use of lectins for both fundamental and applied approaches were discussed to investigate aphid – virus interactions [less ▲]

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See detailMolecular detection of six high importance endosymbiotic bacteria in Belgian wild-caught mosquitoes
Raharimalala, Fara Nantenaina ULg; Boukraa, Slimane ULg; Bawin, Thomas ULg et al

Poster (2014, July)

Introduction Several disease vectors presented a resistance to various pesticides currently used. One of an alternative solution was to use endosymbiotic bacteria because their probably interactive ... [more ▼]

Introduction Several disease vectors presented a resistance to various pesticides currently used. One of an alternative solution was to use endosymbiotic bacteria because their probably interactive effects with their host. According to the introduction risks of mosquito born disease and their dispersion, we propose to investigate the prevalence of six endosymbiontic bacteria in wild-caught Culicidae in Belgium. Methods Eleven species of Belgian fields mosquitoes (Culex pipiens s.l., Cx. torrentium, Cx. hortensis, Anopheles claviger, An. maculipennis s.l., An. plumbeus, Culiseta annulata, Ochlerotatus geniculatus, Oc. dorsalis, Aedes albopictus and Coquillettidia richiardii) were used for the screening of six genera endosymbiotic bacteria (Wolbachia sp., Commamonas sp., Delftia sp., Pseudomonas sp., Acinetobacter sp. and Asaia sp.) according to their possible impact in mosquito biology. PCR was done for the screening and positives bands were sequenced and deposited in GenBank. Results Total of 144 larvae and 32 adults were used. Wolbachia, Pseudomonas, Acinetobacter and Asaia were found in mosquitoes with different proportions, according to stages (adults, larvae) with a predominance of Pseudomonas in all species, as far as Acinetobacter and Asaia also have a high prevalence. Commamonas and Delftia were absent from all species tested, either in larvae and in adults. Discussion Choice of endosymbiotic bacteria studied here was allowing of their importance in literature. For Pseudomonas, it showed that this bacteria could produced ovipositon attractants for mosquito. Acinetobacter was suggested efficient in transmission and maintenance within host populations. Asaia was capable of efficiently crossing body barriers and colonizing different organs. Wolbachia was currently the most studied bacteria which plays an important role in the genetic manipulation of the host. Present advances in understanding the mosquito–microbiota relationships may have a great impact in a better understanding of some traits of mosquito biology and in the development of innovative mosquito-borne disease-control strategies. [less ▲]

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See detailEffects of tillage practices and crop residue exportation on earthworm communities and soil physico-­chemical properties in silt loam arable soil (Belgium)
Lemtiri, Aboulkacem ULg; Colinet, Gilles ULg; Alabi, Taofic ULg et al

Poster (2014, June 08)

Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers due to their capacity to influence a wide range of chemical, physical, and biological ... [more ▼]

Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers due to their capacity to influence a wide range of chemical, physical, and biological properties of soil environments. Therefore, it is important to understand how earthworm communities are impacted by tillage systems and crop management practices. In the present study, earthworm and soil samples were collected from wheat cultivated fields in Gembloux, Belgium under the following four experimental treatments: (1) conventional tillage with crop residues left in the soil (CT/IN); (2) conventional tillage with crop residues removed from the field (CT/OUT); (3) reduced tillage with crop residues left in the soil (RT/IN); and (4) reduced tillage with crop residues removed from the field (RT/OUT). The different tillage systems were applied for four consecutive years prior to the initiation of the current study. Results indicated soil compaction was significantly higher in RT compared with CT up to a depth of 6–49 cm. Significant differences were not detected between residue incorporation depth systems, where results showed mean earthworm abundance was respectively 182.25 and 180 individuals.m-2 in CT and RT. Mean earthworm biomass was similarly not significantly different between CT and RT, where results were respectively 48.52 and 57.27 g.m-2. However, a significant difference was observed between IN and OUT treatments, suggesting the exportation of wheat residues will limit earthworm abundance and biomass in CT and RT plots. Data showed high representation of the endogeic earthworm ecological category, notably N. c. caliginosus regardless of treatment. Despite tillage system and exportation of crop residues, N. c. caliginosus, L. terrestris, and A. r. rosea exhibited high abundance, indicating tolerance to soil environmental conditions. For each depth, measures of soil physico-chemical properties showed significant differences among treatments. Furthermore, soil chemical property attributes were significantly higher in the first soil centimetres compared to lower soil layers. These results were attributable to earthworm activity and wheat residues, suggesting earthworms contributed to nutrient dynamics, particularly at increased soil depths. Overall, the results emphasise the influence of exportation of crop residues on earthworm community and also, the important influence of earthworm activity on soil physico-chemical properties change, processes which are closely linked. [less ▲]

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See detailEffect of entomopathogenic Aspergillus strains against the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae)
Seye, Fawrou; Bawin, Thomas ULg; Boukraa, Slimane ULg et al

in Applied Entomology and Zoology (2014)

Aphids (Homoptera: Aphididae) are sap-sucking insect pests that feed on several plants of agronomical importance. Entomopathogenic fungi are valuable tools for potential aphid control. As part of a ... [more ▼]

Aphids (Homoptera: Aphididae) are sap-sucking insect pests that feed on several plants of agronomical importance. Entomopathogenic fungi are valuable tools for potential aphid control. As part of a selection process, laboratory bioassays were carried with five different concentrations of Aspergillus clavatus (Desmazières), Aspergillus flavus (Link) and Metarhizium anisopliae ((Metschnikoff) Sorokin) spores against the pea aphid, Acyrthosiphon pisum (Harris). Aspergillus isolates induced higher mortalities than M. anisopliae which is a well-known entomopathogen in the literature. Lethal concentrations (LC50 and LC90) were 1.23 x 10^3 and 1.34 x 10^7 spores/ml for A. flavus, 4.95 x 10^2 and 5.65 x 10^7 spores/ml for A. clavatus, and 3.67 x 10^3 and 9.71 x 10^7 spores/ml for M. anisopliae five days after treatment. Mycelia development and sporulation on adult cadavers was observed 48 hours after incubation. The intrinsic growth rate of A. pisum decreased with increased spore concentration for all fungal strains suggesting an increase in pathogen fitness related to a consumption of host resources. In conclusion, Aspergillus species could be useful in aphid control as pest control agents despite their saprophytic lifestyle. This is also in our knowledge the first report of A. clavatus and A. flavus strains pathogenic to aphids. [less ▲]

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See detailInvestigation of differential virus transmission efficiency in aphid strains: from biological to proteomic assays
Bosquée, Emilie ULg; Francis, Frédéric ULg

Poster (2014, June)

Aphids are well known for their variable efficiency in virus transmission to host plant. Not only aphid species but also aphid strain is an important factor to consider in the plant-aphid-virus ... [more ▼]

Aphids are well known for their variable efficiency in virus transmission to host plant. Not only aphid species but also aphid strain is an important factor to consider in the plant-aphid-virus interactions. In order to investigate these relations, different approaches should be developped from biological observations assessing the virus transmission efficiency to molecular tasks to better know the involved mechanisms in the aphid vector. After a period of virus acquisition on an artificial diet (depending on the kind of transmission, permanent or non permanent ways), the virus transmission rate were assayed and followed by the determination of the presence of virus in the aphid by PCR or immudetection. The aphids were then collected to investigate the variation of aphid proteome and potential involvement in virus interactions. Changes in protein expressions were investigated using a 2D-DIGE approach comparing most and least efficient aphid strains selecting different aphid – virus models (PVY and PLRV in potato, BYDV in wheat, CMV on tobacco) . The proteome changes were analysed using the samespot software. Protein spots with significant up- and down expressions were then mechanically picked, trypsin digested and analysed by Maldi-Tof-Tof. Significantly changed proteins were classify according to metablic pathways and biological functions. Interesting proteins found to probably interact with virus were not only detected from aphid but also from related bacterial symbionts. Theses results were discussed in order to better understand virus – vector relations and potentially promote new ways to control virus transmitted by hemipteran pest. [less ▲]

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See detailEffect of plant defence elicitor on aphid and disease cross infestations
Bosquée, Emilie ULg; Oumarou, Saadatou; Qiu, Dewen et al

Poster (2014, June)

Various bio-aggressors can infest potato plants (Solanum tuberosum L.) throughout its life cycle. In addition to aphids, in particular Myzus persicae Sulzer which transmits Potato virus Y (PVY), plant ... [more ▼]

Various bio-aggressors can infest potato plants (Solanum tuberosum L.) throughout its life cycle. In addition to aphids, in particular Myzus persicae Sulzer which transmits Potato virus Y (PVY), plant pathogenic fungus such as Botrytis cinerea are able to cause damage. To determine the interactions between various bio-aggressors on potato plant defence mechanisms, (1) the effect of an attack by M. persicae followed by an attack by B. cinerea and vice versa, as well as (2) the effect of an elicitor on biological parameters of M. persicae and development of B. cinerea were assessed. On the other hand, (3) the effect of Botrytis cinerea and an elicitor on the efficiency of transmission of PVY by M. persicae was examined. The previous infection by B. cinerea resulted in a significant decrease in growth rate and a sharp reduction of M. persicae fertility, while the infection level of B. cinerea followed by M. persicae infestation was non-significant. Despite a reduction in growth and fertility of M. persicae during the first days of observation, the effect of elicitor on the biological parameters of M. persicae as well as on the development of B. cinerea was non-significant. Regarding the investigations on the PVY transmission by M. persicae, when the elicitor or Botrytis is previously applied on the plant, a significant reduction in the rate of transmission was observed. [less ▲]

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See detailInhibitors of glycosylhydrolases as potential insecticides : focus on aphid model
Bosquée, Emilie ULg; Vandermoten, Sophie; Richel, Aurore ULg et al

Poster (2014, June)

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are ... [more ▼]

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are interesting to bring potential specific control of arthropods. Indeed, glycosylhydrolase group is very diversified from glucanases to trehalases, until chitinases. Different kinds of inhibitors were here tested to determine their potential role as new targetted aphicides. After different assays using the selected inhibitors in artificial diets, the most efficient molecules at 50-100 μg ml-1were kept for further proteomic tasks. The proteome patterns of aphids related to different inhibitor treatments were determined by two dimension electrophoresis, 2D-Differencial In Gel Expression (2D-Dige) coupled with mass spectrometry (ESI-MS-MS and Maldi-Tof-MS-MS) and data bank investigations. Particular proteins of interest were selected and accurately characterised with both fundamental but also applied views. Not only the carbohydrate metabolic pathway was disturbed with the use of glycosylhydolases inhibitors, other primary functions were also modified (amino acid synthesis, stress response, etc). This proteomic approach was discussed as an interesting and reliable tool to study the biologically involved proteins from aphids in response to specific tested enzymatic inhibitors with further ideas to be promoted as new insecticides to control insect pests. [less ▲]

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See detailBelowground Chemical Ecology: The Case of Wireworms
Barsics, Fanny ULg; Delory, Benjamin ULg; Delaplace, Pierre ULg et al

Poster (2014, June)

Wireworms, clock-beetles' larvae (Coleoptera, Elateridae), are below ground pests of many crops. They cause dramatic yield losses worldwide. Research on their ecology is crucial to undertake innovative ... [more ▼]

Wireworms, clock-beetles' larvae (Coleoptera, Elateridae), are below ground pests of many crops. They cause dramatic yield losses worldwide. Research on their ecology is crucial to undertake innovative management strategies. In the field of chemical ecology, multitrophic interactions occurring in the rhizosphere are gaining increasing attention from entomologists and agronomists. Our research aims at unveiling the role of volatile organic compounds (VOC) involved in wireworms' foraging behavior, putatively leading to host localization and/or host recognition. [less ▲]

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See detailSynthèse bibliographique : l'écologie larvaire des culicoïdes (Diptera : Ceratopogonidae)
Zimmer, Jean-Yves ULg; Haubruge, Eric ULg; Francis, Frédéric ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18(2), 301-312

Cet article présente une synthèse de l’écologie larvaire des culicoïdes (Diptera : Ceratopogonidae) en vue de rassembler les connaissances, souvent très parsemées, des sites d’oviposition et des habitats ... [more ▼]

Cet article présente une synthèse de l’écologie larvaire des culicoïdes (Diptera : Ceratopogonidae) en vue de rassembler les connaissances, souvent très parsemées, des sites d’oviposition et des habitats larvaires actuellement identifiés à travers le monde pour les principales espèces de culicoïdes. Ces moucherons piqueurs hématophages sont impliqués dans la transmission de divers parasites (protozoaires et filaires) et virus aux animaux. Le développement larvaire des culicoïdes est généralement optimal dans les substrats humides et riches en débris organiques divers. Cependant, chaque espèce présente ses propres exigences écologiques et se trouve par conséquent dans des micro-habitats spécifiques. Dans cette synthèse, les gites larvaires sont répartis en substrats aquatiques et semi-aquatiques d’eau douce et d’eau salée ou saumâtre, substrats terrestres et substrats anthropiques liés à l’élevage. Les gites larvaires de nombreuses espèces appartenant au genre Culicoides Latreille demeurent cependant encore méconnus. La connaissance de ces derniers et leur caractérisation sont pourtant essentielles pour permettre la mise au point de stratégies de lutte efficaces contre ces insectes vecteurs, permettant ainsi de renforcer la vaccination du bétail et les autres moyens de lutte mis en oeuvre. Les habitats larvaires actuellement identifiés pourraient permettre d’orienter les investigations des recherches écologiques futures et les propositions de contrôle de ces moucherons vecteurs. [less ▲]

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See detailTemperature regimes and aphid density interactions differentially influence VOC emissions in Arabidopsis
Hien, Truong Thi Dieu ULg; Delory, Benjamin ULg; Vanderplanck, Maryse et al

in Arthropod-Plant Interactions (2014)

The effects of volatile emissions from plants exposed to individual abiotic and biotic stresses are well documented. However, the influence of multiple stresses on plant photosynthesis and defense ... [more ▼]

The effects of volatile emissions from plants exposed to individual abiotic and biotic stresses are well documented. However, the influence of multiple stresses on plant photosynthesis and defense responses, resulting in a variety of volatile profiles has received little attention. In this study, we investigated how temperature regimes in the presence and absence of the sucking insect Myzus persicae affected volatile organic compound emissions in Arabidopsis over three time periods (0-24 h, 24-48 h, and 48-72 h). Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was used to evaluate Arabidopsis volatile organic compounds. The results showed that under laboratory conditions, eight volatile classes [alcohols (mainly 2-ethyl-hexan-1-ol), ketone (6-methyl hept-5-en-2-one), esters (mainly (Z)-3-hexenyl acetate), aldehydes (mainly phenylacetaldehyde), isothiocyanates (mainly 4-methylpentyl isothiocyanate), terpenes (mainly (E,E)-α-farnesene), nitrile (5-(methylthio) pentanenitrile), and sulfide (dimethyl trisulfide)] were observed on plants exposed to stress combinations, whereas emissions of six volatile classes were observed during temperature stress treatments alone (with the exception of nitriles and sulfides). Aphid density at high temperature combinations resulted in significantly higher isothiocyanate, ester, nitrile and sulfide proportions. The results of the present study provide an insight into the effects of temperature - aphid interactions on plant volatile emissions. [less ▲]

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See detailEvaluation of the aphid and aphidophagous beneficials diversity in a pea and potato association
Bosquée, Emilie ULg; Chevalier Mendes Lopes, Thomas ULg; Serteyn, Laurent et al

Poster (2014, May 20)

Crop associations can have beneficial effects on the control of insect pests. This study was conducted in the Shandong province (China) to assess the impact of potatoes and peas association on the ... [more ▼]

Crop associations can have beneficial effects on the control of insect pests. This study was conducted in the Shandong province (China) to assess the impact of potatoes and peas association on the populations of aphids and aphidophagous beneficials. Observations on potato plants and trapping were performed. During the season, the degree of infestation didn’t differ significantly between the association and the pure stand. However, the aphidophagous beneficials were more abundant in the association comparing to the pure stand. Trapping results give a more general idea about the richness and diversity of natural enemies present in the environment. Aphidius gifuensis (Ashmead) and Aphelinus abdominalis Dalman are the most abundant parasitoids. Among predators, Propylea japonica (Thunberg) and Harmonia axyridis (Pallas) are prevalent. Few hoverflies and lacewings were trapped. Results from the observations on plants do not support the resource concentration hypothesis. However, the enemy hypothesis was confirmed for the aphidophagous beneficials. Therefore, this association can have a beneficial effect on the control of aphid populations. [less ▲]

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See detailEffects of wheat/oilseed rape and wheat/pea associations on the diversity of aphids and aphidophagous beneficials
Chevalier Mendes Lopes, Thomas ULg; Bosquée, Emilie ULg; Honba, David et al

Poster (2014, May 20)

This study was conducted in the Shandong province (China) to better characterize the effect of wheat/oilseed rape and wheat/pea associations on the populations of aphids and aphidophagous beneficials. At ... [more ▼]

This study was conducted in the Shandong province (China) to better characterize the effect of wheat/oilseed rape and wheat/pea associations on the populations of aphids and aphidophagous beneficials. At specific times of the season, the observations on wheat tillers confirm the resource concentration and the enemy hypotheses. In fact, aphids were more abundant in the pure stand of wheat, while more ladybirds were observed in the associations. As for the trapping of aphidophagous beneficials, the parasitoid species Aphidius gifuensis (Ashmead) was prevalent. Among predators, Propylea japonica (Thunberg) and Harmonia axyridis (Pallas) were the most abundant species. Few lacewings and hoverflies were trapped. This study shows a beneficial effect of crop associations on the control of aphid populations. [less ▲]

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See detailFive Years of aphidophagous species sampling in belgian corn
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Durieux, Delphine ULg et al

Poster (2014, May 20)

The community of aphidophagous species present in agroecosystems is disturbed since the introduction of an exotic species the Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera ... [more ▼]

The community of aphidophagous species present in agroecosystems is disturbed since the introduction of an exotic species the Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae). In this intensive agricultural area, five aphids predator species are commonly observed: three coccinellids H. axyridis, Coccinella septempunctata, Propylea quatuordecimpunctata, one hoverfly Episyrphus balteatus, and one lacewing Chrysoperla carnea. This study focuses on the occurrence of the five most abundant aphid predators and their seasonal abundance in corn. The abundance of adults and larvae of these species was evaluated over a five-year period, from 2009 to 2013. The sampling method consisted in the counting of aphids and all developmental stages of aphidophages present in quadrats of 1m² from April to November. Densities of aphid predators changed during five years studies. Since 2011, H. axyridis was the most abundant aphids predators in corn. H. axyridis numbers were found to increase over the first four inventoried year, reaching in 2012 86% for adult stage (119,7±7,8 adults/100m2) and 76% for larvae stages (242,8±14,2 larvae/100m2) of the aphid predators, while in 2009 these ratios were 14% and 23% respectively. For C. septempunctata and P. quatuordecimpunctata the population densities decrease at the end of the five years period. Population densities of C. carnea and E. balteatus were variable during the sampling period but increased in 2013. Phenology of the five studied species presents similar curves following the aphid abundance. The most abundant observed aphids were metopolophium dirhodum, rhopalosiphum padi, rhopalosiphum maidis, sitobion avenae and sitobion fragariae. H. axyridis starts reproducing after the peak in aphid population, suggesting that H. axyridis is able to complete its development by feeding on alternative prey such as larvae and pupae of conspecific and heterospecific. H. axyridis is a bivoltine species but the second generation was stop by the corn harvesting. [less ▲]

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See detailMealworms: Alternate Source of Lipids
Danthine, Sabine ULg; Blecker, Christophe ULg; Paul, Aman ULg et al

Scientific conference (2014, May 16)

The aim of present study was to determine the physicochemical properties of the oil obtained from Tenebrio molitor larvae (mealworms) and explore its potential as edible oil. Five batches of Tenebrio ... [more ▼]

The aim of present study was to determine the physicochemical properties of the oil obtained from Tenebrio molitor larvae (mealworms) and explore its potential as edible oil. Five batches of Tenebrio molitor larvae were investigated for their lipid content and physiochemical properties. Three batches were reared in lab (3 different productions) and two were purchased from a local supplier. The lipids were extracted using a cold extraction technique employing 2:1 ratio chloroform/methanol as solvent. The fatty acid profile was determined using gas chromatography and triacylglycerol profile using HPLC. The thermal properties of the lipid extracts were also analyzed using differential scanning calorimetry. All the samples contained high amount of unsaturated fatty acids. The chemical composition and the thermal properties of the samples varied with the source. With this quantity and quality of lipid content, mealworms offer potential as an important source of edible lipids. [less ▲]

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