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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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See detailBelgian Grasshoppers: A Nutritious Food Source
Paul, Aman ULg; Frederich, Michel ULg; Blecker, Christophe ULg et al

Poster (2014, May 14)

Rapid urbanization and rising economies are creating shifts in the composition of global food demand, so it is necessary to explore new sources of food with better nutritional profile. Among the ... [more ▼]

Rapid urbanization and rising economies are creating shifts in the composition of global food demand, so it is necessary to explore new sources of food with better nutritional profile. Among the alternative food that exists are the grasshoppers, about 80 species of which are consumed worldwide. Grasshoppers are not only rich source of proteins and lipids but also some important minor component like vitamins and minerals. Edible species of grasshopper in Belgium were identified and attempts were made for the lab rearing of meadow grasshopper (Chorthippus parallelus). The lipids as well as protein contents of meadow grasshopper (Chorthippus parallelus) & long winged conehead (Conocephalus discolor) were investigated. The fatty acid compositions of these two species were determined by gas chromatography. Some of the physicochemical properties of the lipids extracted were also analyzed. These two grasshopper species could be really nutritious source of food. [less ▲]

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See detailLocusts and Grasshoppers: Future Foods?
Paul, Aman ULg; Frederich, Michel ULg; Uyttenbroeck, Roel ULg et al

Scientific conference (2014, May 08)

Consuming locusts and grasshoppers as food is not a new concept, because some people have been doing it for a long time and there are many references in the religious literature to support this. About 80 ... [more ▼]

Consuming locusts and grasshoppers as food is not a new concept, because some people have been doing it for a long time and there are many references in the religious literature to support this. About 80 locust and grasshopper species are consumed worldwide, and the large majority of grasshopper species are edible. From the nutritional point of view they are an excellent source of proteins, lipids and other minor components like vitamins and minerals. They are an excellent source of amino acids and their lipids contain a large majority of unsaturated fatty acids. Environmentalists have supported human consumption of grasshoppers owing to the facts that they usually appear as pests. Using them as food could help reduce their population and result in limited application of harmful pesticides. Their production usually generates lesser amount of greenhouse gases & ammonia; a lower amount of water is required for their production in comparison to conventional proteins sources. Some species of grasshoppers usually feed on dead organic matter, this reduces the environmental load. In the developing world, catching of grasshoppers and selling them for human consumption has played a key role in improving the livelihood of women and underprivileged children. Eating grasshopper and locust is not a very common practice in temperate areas. However it is a very common practice in the tropical areas of world because of the higher density, bigger size of the insect and yearlong availability in such areas. To encourage their consumption in temperate areas, it is now necessary to perform accurate research regarding food safety (minor components, toxicity, allergens,…) but also to develop value added products to make it easier for people to adapt with entomophagy. Furthermore we have to develop methods for commercial production and organize awareness campaigns to explain about the nutritional and other benefits related to locust & grasshopper consumption as food to people. [less ▲]

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See detailPhylogenetic study of Aedes albopictus and Aedes koreicus (Diptera, Culicidae) origin, two invasive mosquito species in Belgium
Raharimalala, Fara Nantenaina ULg; Boukraa, Slimane ULg; Bawin, Thomas ULg et al

Poster (2014, April 10)

The main ways of the introduction of invasive mosquito species in Europe were greatly facilitated by the importation of used tires and plants from the South of China (Dracaena sanderiana, called "Lucky ... [more ▼]

The main ways of the introduction of invasive mosquito species in Europe were greatly facilitated by the importation of used tires and plants from the South of China (Dracaena sanderiana, called "Lucky bamboo"), which are a very good breeding sites of these mosquitoes (www.eidatlantique.eu). For Belgium, several species of exotic mosquitoes have already been listed such as Ochlerotatus japonicus japonicus, Aedes albopictus and A. koreicus. We have captured one male of A. albopictus in Belgium in July 2013 (Boukraa et al, 2013), and teams from other entomologist have been able to find several individuals in the months that have followed our discovery (personal communication). However, his presence was reported first in 2000 (Schaffner et al. 2004) but until 2012, no individuals have been found (Versteirt et al., 2013). We also could find larvae of A. koreicus in abundance. These discovery suggest that these two invasive species are being established in Belgium. Methods: Adult mosquitoes were collected by CO2-baited traps Mosquito Magnet Liberty Plus (MMLP) and immature stages by the dipping method from 8 sites of Belgium. Each individual was then determined morphologically. For A. albopictus and A. koreicus, reconfirmation by molecular method was performed with COI and ND5 mitochondrial primers and sequences were then aligned with those of mosquitoes available in databases by using BioEdit and Multialn softwares. The two gene sequences were concatenated to improve the reliability of the phylogenetic analysis and were carried out by using the Seaview software based on maximum likelihood (ML) methods. Trees were then constructed with the general time reversible (GTR) model, and branch supports were estimated by bootstrapping with 1000 replicates. Result: The aim of this work will focus on the study of the probable origin of these two species of Aedes, which are for the moment safe yet, but that might become dangerous in the event of massive outbreak. The knowledge of the probably origin of the two invasive mosquitoes allow take more protection against their way to enter in the country. [less ▲]

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See detailBiological control of aphids in wheat and vegetable crops : a multi-approach case study in Shandong province (China)
Chevalier Mendes Lopes, Thomas ULg; Bosquée, Emilie ULg; Chen, Julian et al

Poster (2014, April 02)

This multi-approach study was conducted in the Shandong province (China) to assess the effectiveness of different biological control methods against aphids in wheat and vegetable crops. Three approaches ... [more ▼]

This multi-approach study was conducted in the Shandong province (China) to assess the effectiveness of different biological control methods against aphids in wheat and vegetable crops. Three approaches were tested: (1) wheat/oilseed rape and wheat/pea associations, (2) potatoes/peas association, and (3) E-β-farnesene (aphid alarm pheromone) releasers in squashes under plastic tunnels. Aphids and aphidophagous beneficials were monitored by observations on plants. Wheat associations and E-β-farnesene reduced aphid infestations compared with control treatments, while no effect was observed in the potatoes/peas association. Moreover, aphidophagous beneficials were significantly more abundant in the three kinds of associations compared with control treatments. Few individuals were observed on squashes. Additionally, adult aphidophagous beneficials were monitored using yellow pan traps. The parasitoid species Aphidius gifuensis (Ashmead) was prevalent, while Propylea japonica (Thunberg) and Harmonia axyridis (Pallas) were the most abundant species among predators. Globally, wheat associations were more efficient to reduce aphid infestations and attract aphidophagous beneficials to promote biological control. The trapping of natural enemies allowed to assess the diversity and abundance of aphidophagous species in this region. This study shows a beneficial effect of crop associations and E-β-farnesene on the control of aphid populations and contributes to assess the potentialities of these alternative methods to the use of insecticides. [less ▲]

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See detailConservatoire entomologique de Gembloux Agro-Bio Tech: les coccinelles de Wallonie et de Bruxelles de 2001 à 2009
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Durieux, Delphine ULg et al

Poster (2014, April 02)

Un inventaire des Coccinellidae présents au sein de la collection de l’unité d’Entomologie fonctionnelle et évolutive (ULg - Gembloux Agro-Bio Tech) a été réalisé sur la période s’étendant de 2001 à 2009 ... [more ▼]

Un inventaire des Coccinellidae présents au sein de la collection de l’unité d’Entomologie fonctionnelle et évolutive (ULg - Gembloux Agro-Bio Tech) a été réalisé sur la période s’étendant de 2001 à 2009. Cette collection est essentiellement constituée par les récoltes des étudiants de première Bachelier de Gembloux Agro-Bio Tech. A travers ce recensement, nous avons étudié l’évolution des espèces récoltées au sein de cette famille en termes d’effectif relatif et de richesse spécifique. Notre étude s’est focalisée sur les données issues de Wallonie et de la Région de Bruxelles-Capitale, trop peu de collectes ayant été réalisées en Flandre. Parmi les individus identifiés, 27 espèces ont été observées, dont 21 appartiennent à la sous-famille des Coccinellinae, 2 à celle des Epilachninae et 4 à celle des Chilocorinae. La plupart des espèces sont communes à la Belgique. Cependant, Harmonia axyridis (Pallas 1773), espèce originaire du sud-est de l’Asie, a été introduite sur le territoire belge en 1997. Cette coccinelle exotique fait son apparition dans les récoltes de 2002 et son effectif ne cesse d’augmenter au fil des années prospectées. En parallèle à cette augmentation, une diminution de la richesse spécifique, ainsi que de l’effectif relatif d’Adalia bipunctata (L. 1758), de Propylea quatuordecimpunctata (L. 1758) et de Psyllobora vigintiduopunctata (L. 1758), est observée. [less ▲]

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See detailStudy of sex ratio and morphotypes of the Multicoloured Asian Ladybird, Harmonia axyridis Pallas in Belgian corn
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Barsics, Fanny ULg et al

Poster (2014, April 02)

Several insect species are known to have different morphotypes, an adaptation to heterogeneities in changing environments. This phenotypic plasticity could be a factor used by the Multicoloured Asian ... [more ▼]

Several insect species are known to have different morphotypes, an adaptation to heterogeneities in changing environments. This phenotypic plasticity could be a factor used by the Multicoloured Asian Ladybird, which is considered as an invasive species in Europe since its introduction in the 80’s. Harmonia axyridis has four major morphotypes: 2 melanic forms, conspicua and spectabilis; and 2 non-melanic, succinea and axyridis. In Belgium, only the three first are observed. Literature reports variations in morphotype frequencies, across native and introduced strains. These variations seem to be linked to climate (geographical and seasonal variation), with non-melanic forms being the most abundant in hot and arid climate. This study focused on the variation of morphotype abundance in H. axyridis according to season, field and gender. Adult ladybirds were caught from mid-July to mid-October 2012 into 5 corn fields. The proportions of observed morphotypes were compared according to the sampling season. The abundance of morphotypes was not significantly different through the fields; the observed ratios were 81.6%, 15% and 3.4% for succinea, spectabilis and conspicua respectively. Succinea was the most observed morphotype (χ2=755.8; P<0.001). The total number of collected males and females was the same with ratios of 48.2% and 51.8%: (χ2=0.93; P=0.33). The sex ratio was also not significantly different for each morphotype. There was no evolution of melanic and non-melanic form ratio according to the season, with 25.6% of melanic form in summer and 20.6% in autumn (χ2=1.22; P=0.27). Our results seem to show that morphotype adaptation according to the climate is not observed for Belgian ladybirds. We discuss these results according to all environmental data available. [less ▲]

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See detailWill top-down interactions be affacted by climate change?
Boullis, Antoine ULg; Verheggen, François ULg; Francis, Frédéric ULg

Poster (2014, April 02)

Greenhouse gas emissions are rising since the beginning of the industrial era: atmospheric carbon dioxide now exceeds 400 ppm (30% increase since the mid-1800s) and tropospheric ozone has reached 40 ppb ... [more ▼]

Greenhouse gas emissions are rising since the beginning of the industrial era: atmospheric carbon dioxide now exceeds 400 ppm (30% increase since the mid-1800s) and tropospheric ozone has reached 40 ppb in industrialized areas. According to forecasting models, these concentrations are expected to double by the end of the 21st century. To date, impacts of elevated greenhouse gases have been extensively studied in plant-insect interactions, whereas interactions between herbivores and their natural enemies have been neglected. Because most interactions between herbivorous insects and their natural enemies are orchestrated by natural molecules produced as semiochemicals, we hypothesize that modification in atmospheric gas composition will alter chemical communication in insects, and affect the performance of natural enemies to locate their prey. In this project, we shall attempt to analyze the effect of increase in greenhouse gas concentrations on insect communication, particularly in top-down interactions. The study model will consist in the interactions between the pea aphids (Acyrthosiphon pisum (Harris)) and their natural enemies Harmonia axyridis (Pallas) and Episyrphus balteatus (DeGeer). Under elevated CO2 and/or O3 concentrations, we will quantify the production of several aphid semiochemicals that are currently used as kairomones by natural enemies, including the aphid alarm pheromone E-β-farnesene and honeydew volatile compounds. Olfactometry assays will then be set up to examine the ability of natural enemies to locate their prey in the predicted atmospheric conditions of the end of the 21st century. Finally, using an Ecotron structure to be built in Gembloux Agro-Bio Tech, we will simulate a future ecosystem with the possibility to control additional biotic and abiotic parameters. [less ▲]

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