References of "Francis, Frédéric"
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See detailOccurrence of aphid predator species in both organic and conventional corn and broad bean
Vandereycken, Axel ULg; Joie, Emilie ULg; Francis, Frédéric ULg et al

in Entomologie Faunistique = Faunistic Entomology (2013), 66

Organic farming has been suggested to enhance beneficial species abundance and diversity in agrosystem habitats. In this study, the abundance of aphid predators was compared in organic and conventional ... [more ▼]

Organic farming has been suggested to enhance beneficial species abundance and diversity in agrosystem habitats. In this study, the abundance of aphid predators was compared in organic and conventional corn and broad bean fields during a two-year inventory. In both farming strategies, there were no differences between species diversity. Five aphid predator species were mainly observed: Coccinella septempunctata L. 1758 (Coleoptera: Coccinellidae), Propylea quatuordecimpunctata (L. 1758) (Coleoptera: Coccinellidae), Harmonia axyridis Pallas 1773 (Coleoptera: Coccinellidae), Chrysoperla carnea (Stephens 1836) (Neuroptera: Chrysopidae) and Episyrphus balteatus (De Geer 1776) (Diptera: Syrphidae). Differences in abundance of aphidophagous species between conventional and organic crop fields were observed even if not always in favour of the latter condition. The abundance of the five above- mentioned aphidophagous species varied for the most part according to almost all the observed parameters, including sampled year, crop and agricultural practices. In conclusion, our findings do not support organic practices in corn and broad bean as key options to increase the biodiversity and abundance of aphid natural enemies. [less ▲]

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See detailEmission of sulfur-containing volatiles from Arabidopsis thaliana (L.) Heynh Col-0 related to diamondback moth (Plutella xylostella (L.)) infestation
Hien, Truong Thi Dieu ULg; Delaplace, Pierre ULg; Francis, Frédéric ULg et al

Poster (2013, June 10)

Herbivore-infested plants often release a variety of volatile organic compounds (VOCs). Here, we studied the effects of feeding Plutella xylostella (L.) (0, 3, 9, 20 pest larvae within 0-4 h and 4-8 h ... [more ▼]

Herbivore-infested plants often release a variety of volatile organic compounds (VOCs). Here, we studied the effects of feeding Plutella xylostella (L.) (0, 3, 9, 20 pest larvae within 0-4 h and 4-8 h infestation, respectively) on the emission of sulfur-containing VOCs in Arabidopsis thaliana (L.) Heynh Col-0 (A.t. Col-0) by headspace solid-phase micro-extraction coupled to gas chromatography - mass spectrometry (HS-SPME-GC/MS). The analytical results showed that the relative emission of sulfur-containing metabolites increased significantly in Arabidopsis plants subjected to P. xylostella infestation according to the density and residence duration of pest larvae on shoot organs. The main compound from infested plants was dimethyl disulfide. We suggest that the correlations between the stress level (density and time infestation) and the sulfides observed in this study provide a means to understand the changes of VOCs profile of plant under chewer infestation. [less ▲]

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See detailIsolation and cultivation of cellulolytic and xylanolytic bacteria and molds extracted from the gut of the termite Reticulitermes santonensis (3DV.1.14)
Tarayre, Cédric ULg; Bauwens, Julien ULg; Mattéotti, Christel et al

Poster (2013, June)

Biofuel production can be based on the use of agro-residues, consisting in a complex lignocellulosic structure which is not easily hydrolysable. The digestive tract of the termite Reticulitermes ... [more ▼]

Biofuel production can be based on the use of agro-residues, consisting in a complex lignocellulosic structure which is not easily hydrolysable. The digestive tract of the termite Reticulitermes santonensis contains a diversified microflora able to hydrolyze the wood components. Bacteria, molds and protists form efficient consortia, able to break the lignocellulosic complex by producing enzymes, such as xylanases and cellulases. Our purpose is the isolation of microbial strains from termite guts in order to evaluate their potential for hydrolysis of lignocellulosic materials. Termites were fed using different diets chosen to improve the xylanolytic and cellulolytic microflora: wood, microcristalline cellulose (added with lignin or not), α-cellulose (added with lignin or not) and birchwood xylan. Then, dissections were realized to isolate the potential xylanolytic and cellulolytic strains. This approach led us to isolate and to study several strains of bacteria (Bacillus sp. strain CTGx and Chryseobacterium sp. strain CTGx) and molds (Trichoderma virens strain CTGx and Sarocladium kiliense strain CTGx). These microorganisms were able to hydrolyze starch, xylan, cellulose, carboxymethylcellulose, esculin, β-glucan and Whatman® filter paper. They can produce glucose and xylose monomers and oligomers which can be further fermented to produce bioethanol. [less ▲]

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See detailResearch of New Enzyme Producing Strains in the Gut of the Termite Reticulitermes santonensis
Tarayre, Cédric ULg; Bauwens, Julien ULg; Mattéotti, Christel et al

Poster (2013, June)

Termites contain a complex microflora inside of their guts. Inferior termites contain bacteria, mycetes and protists that interact to degrade vegetable components. These strains act as consortia to break ... [more ▼]

Termites contain a complex microflora inside of their guts. Inferior termites contain bacteria, mycetes and protists that interact to degrade vegetable components. These strains act as consortia to break natural materials by secreting various enzymes. Our aim was the isolation and cultivation of microorganisms in order to produce new enzymes that can be further used in green chemistry. Termites were fed with different diets: pinewood, microcristalline cellulose (added with lignin or not), α-cellulose (added with lignin or not) and birchwood xylan. Then, dissections were realized to isolate interesting strains. All the microorganisms were subjected to enzyme assays. That technique allowed us to isolate and to cultivate various strains of bacteria, molds and protists. Three strains of bacteria, two strains of molds and one strain of protist were isolated and displayed different enzymatic activities. The bacteria Bacillus subtilis strain ABGx, Bacillus sp. strain CTGx and Chryseobacterium sp. strain CTGx displayed amylase, cellulase and xylanase activities. The molds Trichoderma virens strain CTGx and Sarocladium kiliense strain CTGx were also able to produce those enzymes. However, the protist Poterioochromonas sp. was found to produce only amylase. In conlusion, the termite gut is a complex culivation medium that provides a habitat for many microorganisms that show interesting enzymatic activities. [less ▲]

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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 ▲]

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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)

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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 ▲]

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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)

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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 ▲]

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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 ▲]

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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 ▲]

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