References of "Francis, Frédéric"
     in
Bookmark and Share    
Full Text
See detailApplication of three entomopathogenic fungi for aphid control
Bawin, Thomas ULg; Seye, Fawrou; Boukraa, Slimane ULg et al

Poster (2013, May 21)

Aphids (Homoptera: Aphididae) are sap-sucking insect pests that feed on several plants of agronomical importance. Chemical pesticide application is the most commonly used method for aphid control. Due to ... [more ▼]

Aphids (Homoptera: Aphididae) are sap-sucking insect pests that feed on several plants of agronomical importance. Chemical pesticide application is the most commonly used method for aphid control. Due to rapid developments of resistance to pesticides and environmental pollution, integrated pest management, including biological control was promoted. In this context, entomopathogenic fungi are valuable tools for potential aphid control since various fungal strains are already commercially available. The present study aims to evaluate and compare the insecticidal activity of two Metarhizium and one Aspergillus strains against Acyrthosiphon pisum aphid. Fungi were cultivated on wheat bran media in flasks up to sporulation. The solid media were washed with aqueous solutions containing 0.05% Tween 80 before filtration. The content of conidia was determined by haemocytometer. Doses ranging from 10^3 to 10^7 conidia/ml were then applied on young plants with 20 adult parthenogenetic aphids. Batches were incubated at a 16L/8D photoperiod, 25±2°C and 75-80% relative humidity. Adult mortality was assessed in order to determine LD50, LD90 and LT50 values, and the number of nymphs produced was daily recorded. Five days after treatment, mortality rates ranged from 30 to 91% depending on the fungal strain and tested dose. Corresponding LD50 and LD90 values were 1.23 x 10^3 and 1.34 x 10^7, 3.67 x 10^3 and 9.71 x 10^7, 4.95 x 10^2 and 5.65 x 10^7 conidia/ml for Metarhizium sp., Metarhizium anisopliae and Aspergillus clavatus respectively. At the higher dose, the LT50 were reached within 2, 4 and 3 days respectively, whereas the LT50 were never reached in the controls. By contrast, the intrinsic growth rates were significantly different from uninfected aphids only in the case of A. clavatus with 10^6 and 10^7 conidia/ml doses five days after exposure. In conclusion, these fungal isolates induced A. pisum mortality with a similar impact and A. clavatus infection appeared to alter the adults’ fitness. This suggests that these fungi may be candidates for aphid control. Further investigations should be made in order to assess their host range specificity. Toxic metabolites leading to death have to be identified and their safety towards non-target organisms confirmed. Finally, their persistence in the environment as well as the compatibility with over means of aphid control must be verified in a view of a broad integrated pest management. [less ▲]

Detailed reference viewed: 119 (24 ULg)
Peer Reviewed
See detailAlternative methods for virus control: the role of symbionts and lectins in viral transmission
Bosquée, Emilie ULg; Chen, Ju Lian; Yong, Lui et al

Conference (2013, May 16)

Detailed reference viewed: 39 (15 ULg)
Full Text
See detailLa mortalité de l'abeille domestique : entre communication médiatique et scientifique
Leclercq, Gil ULg; Francis, Frédéric ULg; Haubruge, Eric ULg et al

Conference given outside the academic context (2013)

A l’heure actuelle, plus personne n’ignore que nos populations d’abeilles domestiques subissent de lourdes pertes, chez nous comme dans de nombreux autres pays. Les médias ont axés leur communication sur ... [more ▼]

A l’heure actuelle, plus personne n’ignore que nos populations d’abeilles domestiques subissent de lourdes pertes, chez nous comme dans de nombreux autres pays. Les médias ont axés leur communication sur des messages très simples. On en retient surtout que les pesticides tuent nos abeilles. La conclusion au problème est dès lors évidente : il faut interdire les pesticides. Mais cette problématique est-elle si simple ? Ce message est-il le même que celui communiqué par les scientifiques ? Cette conférence permettra de faire le point sur les pertes en colonies d’abeilles domestiques. On s’intéressera plus particulièrement aux pertes de ces dernières années en Belgique, cartes et chiffres à l’appui. On y verra aussi comment chacun, qu’il soit citoyen, apiculteur, agriculteur,… peut aider à enrayer cette mortalité effrayante. [less ▲]

Detailed reference viewed: 87 (11 ULg)
Full Text
Peer Reviewed
See detailChanges of soil structure and earthworm community under different agricultural management
Lemtiri, Aboulkacem ULg; Alabi, Taofic; Francis, Frédéric ULg et al

Conference (2013, April 11)

The living soil is represented by soil biota that interacts with aboveground biota and with the abiotic constructs of soil, represented as soil structure, organic matter, and nutrients. Maintenance of ... [more ▼]

The living soil is represented by soil biota that interacts with aboveground biota and with the abiotic constructs of soil, represented as soil structure, organic matter, and nutrients. Maintenance of soil organic matter through integrated soil fertility management is necessary for soil quality and agricultural productivity. Earthworms are key actors in soil structure formation through the formation of casts and the incorporation of soil organic matter in the soil. Little is known about the interactive effects of various tillage and crop residue management practices on earthworm populations and physical properties of soil. <br />To investigate the impacts of two tillage management systems and two cropping systems on earthworms populations and soil stucture dynamics, we carried out a three years study of the earthworm communities in experimental site having for experimental treatments : two tillage management systems and two cropping systems. In consequence, the aims of this experimentation were to determine the effects of the tillage systems on the abundance, biomass and diversity of earthworms and examine temporal variation of soil structure and dynamics of nutrient elements. <br />The first results reveal that tillage management had a significant affect on earthworm abundance and biomass. However, crop residue management did not affect abundance, biomass and diversity of earthworms. The analyze of nutrient element dynamics showed that some nutrient elements (phosphore,…) decrease with tillage practice. This study has shown that soil structure was variable within the fields and between them, although the successive cultivation operations and the equipement used for wheat cropping were identical in the study site. [less ▲]

Detailed reference viewed: 70 (24 ULg)
Full Text
Peer Reviewed
See detailÉtude de la virulence des sérotypes 4 et 9 du virus de la peste équine dans deux modèles murins
De la Grandière de Noronha Cotta, Maria Ana ULg; Zonta, William ULg; Dal Pozzo, Fabiana ULg et al

Poster (2013, April)

Objectifs Le virus de la peste équine (African horse sickness virus ; AHSV) est un virus segmenté à ARN double brin, appartenant à la famille des Reoviridae et au genre Orbivirus. L’AHSV se différencie en ... [more ▼]

Objectifs Le virus de la peste équine (African horse sickness virus ; AHSV) est un virus segmenté à ARN double brin, appartenant à la famille des Reoviridae et au genre Orbivirus. L’AHSV se différencie en 9 sérotypes distincts et est transmis par la piqûre d’un vecteur, principalement Culicoides imicola. L’AHSV cause une sévère morbidité et un taux de mortalité qui peut atteindre 95 % chez les chevaux avec de lourdes conséquences économiques. L’établissement d’un modèle d’étude en souris est nécessaire pour plusieurs applications, comme l’investigation de la pathogénie de ce virus, l’étude de la virulence, l’étude d’efficacité de nouveaux vaccins. Méthodes Deux modèles murins, soit une lignée de souris déficientes en récepteur à l’interféron α (A129 KO ou IFNAR -/-), et une lignée immunocompétente (A 129 WT) ont été testées. Les virus de sérotypes 4 et 9 de l’AHSV ont été utilisés pour les inoculations des souris ; ces deux sérotypes ont été à l’origine des épidémies observées en Espagne en 1969 et à la fin des années 80 en Espagne et au Portugal. Le virus a été inoculé par voie sous-cutanée (SC) et/ou par voie intra-nasale (IN) et un groupe de souris témoin (mock-infected) a été utilisé pour les deux modèles testés. Des échantillons de sang ont été prélevés de chaque souris infectée et témoin à intervalles réguliers. Les organes (foie, rate, reins, poumon et cerveau) ont été prélevés à la fin de l’expérience pour la plupart des souris ou lors de l’euthanasie des souris qui présentaient des signes cliniques très prononcés. Tous les échantillons, sang et organes, ont été analysés par qRT-PCR avec comme cible le segment 7 codant la protéine VP7 de l’AHSV qui est la protéine de structure la plus conservée entre les différents sérotypes. Résultats Les deux sérotypes de l’AHSV ont été détectés par qRT-PCR jusqu’à 3 semaines post-infection (ce qui correspond à la fin de l’expérience) dans le sang des souris IFNAR -/- et A129 WT infectées par la voie SC. Le virus de sérotype 4 atteint des niveaux de virémie légèrement plus élevés par rapport au virus de sérotype 9. Les souris A129 WT infectées par la voie intra-nasale ne montrent à aucun moment de l’expérience de virémie détectable par la qRT-PCR. Le pic de virémie a été mesuré entre le jour 2 et le jour 4 post-infection pour les deux lignées de souris. Au pic de virémie, la quantité de ADNc correspondant au segment-7 viral, après quantification par qRT-PCR, était plus élevée chez les souris IFNAR -/-. Conclusions Les souris immunodéficientes (IFNAR -/-) présentent des caractéristiques cliniques et biologiques permettant l’établissement d’un modèle in vivo pertinent. Selon les premiers résultats obtenus, il semble que la voie sous-cutanée soit la voie à privilégier pour les expériences in vivo futures. La mise au point de ce modèle sur souris permet de disposer d’un outil efficace et nécessaire pour l’étude in vivo de l’AHSV, afin de caractériser in vivo la virulence de ce virus et de suivre l’évolution des populations virales pendant la multiplication virale in vivo. Remerciements Recherche financée par le service Recherche Contractuelle, Service Public Fédérale, Santé Publique, Sécurité de la Chaîne alimentaire et Environnement (RT 12/6262 INDEVIREQ 2.0) [less ▲]

Detailed reference viewed: 32 (12 ULg)
Full Text
Peer Reviewed
See detailEvaluation de la diversité de l’entomofaune en cultures maraîchères dans l’est de la Chine
Polo Lozano, Damien ULg; Bosquée, Emilie ULg; Chevalier Mendes Lopes, Thomas ULg et al

in Entomologie Faunistique = Faunistic Entomology (2013), 66

Within the framework of research aimed at developing biological control in vegetable crops in Shandong province in China, a pest and associated auxiliary entomophagous insects monitoring was conducted to ... [more ▼]

Within the framework of research aimed at developing biological control in vegetable crops in Shandong province in China, a pest and associated auxiliary entomophagous insects monitoring was conducted to determine entomological groups of agricultural interest and compare them to the situation in Belgium. The diversity and abundance of the entomofauna were assessed in potato and zucchini fields between May 9th and June 13th, 2011, using yellow traps and in situ observations on host plants. A total of 36 466 and 34 806 insects were trapped or observed on the plants in zucchini and potato fields, respectively. Ten orders and more than sixty families in each crop were identified. Aphids widely predominated in the traps and exerted a strong pressure on both crops early in the season. Other families of pests have been identified but no specific pest of these two crops and the investigated region is among the collections. [less ▲]

Detailed reference viewed: 132 (47 ULg)
Full Text
Peer Reviewed
See detailLaboratory and semi-field environment tests for the control efficacy of Metarhizium anisopliae formulated with neem oil (suneem) against Anopheles gambiae s.l. adult emergence
Seye, Fawrou; Ndione, Raymond Demba; Touré, Mamour et al

in Academia Journal of Biotechnology (2013), 1(3), 46-52

Metarhizium anisopliae was evaluated previously in Suneem formulation against malaria vector adults. However, their ability to control aquatic stages is not yet evaluated. In laboratory conditions: the ... [more ▼]

Metarhizium anisopliae was evaluated previously in Suneem formulation against malaria vector adults. However, their ability to control aquatic stages is not yet evaluated. In laboratory conditions: the lethal dose (LD90) of the formulation was determined on Anopheles gambiae larvae collected from breeding sites and evaluated into artificial vats at dry and rainy seasons. In laboratory conditions, the LD90 was 5.3 × 106 spores/ml in 48 h. In semi-field environment, the formulation had a great emergence inhibition of mosquito adult (P < 0.0001). The emergences rate at day 8 were 2.25 ± 0.03, 28.00 ± 1.07 and 97.25 ± 1.56 % in dry season for the oil formulation (OF), Suneem (S), and water control respectively. In rainy season, the emergences were 1.25 ± 0.15, 30.25 ± 1.23 and 98 ± 0.76 % respectively. No significant difference was observed between dry and rainy seasons (P=0.3). Therefore, M. anisopliae formulated with Suneem may provide a more sustainable management strategy for malaria vectors control at larval stages. [less ▲]

Detailed reference viewed: 96 (21 ULg)
Full Text
See detail11. Perspectives - 2. La culture en association de froment et de pois: une opportunité pour réduire l'abondance des pucerons en été
Lopes, T.; Bodson, Bernard ULg; Francis, Frédéric ULg

in Bodson, Bernard; Destain, Jean-Pierre (Eds.) Livre Blanc - Céréales (2013, February 27)

Detailed reference viewed: 14 (2 ULg)
Full Text
Peer Reviewed
See detailDevelopment of a test to assess the Banana Bunchy Top Virus transmissibility through direct analysis of its aphid vector Pentalonia nigronervosa
De Clerck, Caroline ULg; Francis, Frédéric ULg; Lepoivre, Philippe ULg et al

in Communications in Agricultural and Applied Biological Sciences (2013), 78(1), 49-54

Detailed reference viewed: 78 (19 ULg)
Full Text
Peer Reviewed
See detailImpact de substances informatives utilisées pour le contrôle des pucerons de céréales sur la diversité et l’abondance de l’entomofaune non cible
Bayendi-Loudit, Sandrine ULg; Bodson, Bernard ULg; Francis, Frédéric ULg

in Entomologie Faunistique = Faunistic Entomology (2013), 65

Wheat is one of the most cultivated cereals in the world. However, this crop is under attack by many pests and pathogens. In order, to avoid the massive use of the chemicals, other cropping systems ... [more ▼]

Wheat is one of the most cultivated cereals in the world. However, this crop is under attack by many pests and pathogens. In order, to avoid the massive use of the chemicals, other cropping systems semiochemicals can be adopted for a better management of the pests. This study aims to evaluate the use of three semiochemicals ((E)-β-farnesene (EBF), garlic extract and (Z)-3-hexenol) and paraffin on the entomofauna of wheat. This study was conducted at Gembloux Agro-Bio Tech’s experimental farm for nine weeks. Two techniques were used for collecting insects: yellow traps and visual monitoring. The collected insects were sorted, counted and classified taxonomically to the family or species level. This study highlighted the presence of a great diversity of families with EBF treatment and a better proportion of pest and beneficial insects with the smallest quantity of Aphididae. The latter are the most abundant pests on the entire field whatever the considered treatment. The main encountered pests are from Curculionidae, Cecidomyiidae and Chloropidae. Although Chrysomelidae was not high, some damages were observed at the field. [less ▲]

Detailed reference viewed: 17 (1 ULg)
Full Text
Peer Reviewed
See detailSymbiont Diversity in Reticulitermes santonensis (Isoptera: Rhinotermitidae): Investigation Strategy Through Proteomics.
Bauwens, Julien ULg; Millet, Catherine ULg; Tarayre, Cédric ULg et al

in Environmental entomology (2013), 42(5), 882-7

The complex microbial community living in the hindgut of lower termites includes prokaryotes, flagellates, yeasts, and filamentous fungi. Many microorganisms are found in the termite gut, but only a few ... [more ▼]

The complex microbial community living in the hindgut of lower termites includes prokaryotes, flagellates, yeasts, and filamentous fungi. Many microorganisms are found in the termite gut, but only a few are thought to be involved in symbiotic association to participate in cellulose digestion. Proteomics provides analyses from both taxonomical and functional perspectives. We aimed to identify symbiont diversity in the gut of Reticulitermes santonensis (Feytaud), via complementary electrospray ionization associated to ion trap tandem mass spectrometry (LC-MS/MS) and two-dimensional gel electrophoresis associated to matrix-assisted laser desorption-ionization-time-of-flight mass spectrometry analysis. One specific challenge to the study of lower termites is the relatively few data available on abundant symbiotic flagellates. Analysis based on LC-MS/MS revealed few protein families showing assignments to eukaryotes and the taxonomic origin of highly represented actins could not be established. Tubulins proved to be the most suitable protein family with which to identify flagellate populations from hindgut samples using LC-MS/MS, compared with other protein families, although this method targeted few prokaryotes in our assay. Similarly, two-dimensional gel electrophoresis associated to matrix-assisted laser desorption-ionization-time-of-flight mass spectrometry did not succeed in identifying flagellate populations, but did permit the identification of most of the prokaryotic components of the symbiotic system. Finally, fungi and yeasts were identified by both methods. Owing to the lack of sequenced genes in flagellates, targeting tubulins for LC-MS/MS could allow fingerprints of flagellate populations to be established. Experimental and technical improvements might increase the efficiency of identification of prokaryotic populations in the near future, based on metaproteomic development. [less ▲]

Detailed reference viewed: 29 (9 ULg)
Full Text
Peer Reviewed
See detailComparative analyses of salivary proteins from three aphid species
Vandermoten, Sophie ULg; Harmel, Nicolas; Mazzucchelli, Gabriel ULg et al

in Insect Molecular Biology (2013), under publication

Detailed reference viewed: 58 (11 ULg)
Full Text
Peer Reviewed
See detailInfluence of Garlic Intercropping or Active Emitted Volatiles in Releasers on Aphid and Related Beneficial in Wheat Fields in China
Haibo, Zhou; Chen, Julian; Yong, Liu et al

in Journal of Integrative Agriculture (2013), 12(3)

Detailed reference viewed: 16 (1 ULg)