References of "Lognay, Georges"
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See detailA semiochemical enhancing the attractiveness of aphidophagous predators in potato crops
Leroy, Pascal ULg; Vandereycken, Axel ULg; Sabri, Ahmed ULg et al

Poster (2011, May 24)

Aphids are major pests of crops worldwide and the use of pesticides has led to resistant populations. The integration of aphid natural enemies in integrated management programs could be an option, but ... [more ▼]

Aphids are major pests of crops worldwide and the use of pesticides has led to resistant populations. The integration of aphid natural enemies in integrated management programs could be an option, but their efficacy is often limited by their quick dispersal from the ecosystem where they are released. Here, using wind-tunnel and field experiments, we have demonstrated that 3-Methyl-2-butenal acts as an efficient attractant and ovipositional stimulant for the hoverfly Episyrphus balteatus (De Geer) (Diptera: Syrphidae), enhancing its efficiency as biological control agent in crop fields. Wind-tunnel assays allowed determining that a minimal dose of 250 µg of 3-Methyl-2-butenal is required to attract the hoverflies over a distance of 2.5 m while a minimal dose of 500 µg is needed to induce the oviposition. Both attraction and oviposition increased proportionally to the tested doses showing that hoverflies are able to regulate their oviposition according to the chemical stimuli from their environment. In field experiments, both Syrphidae and Chrysopidae were strongly attracted by the 3-Methyl-2-butenal at a dose of 10 mg which also induces the oviposition of these two aphid predators in potato crops. This study also highlighted that hoverflies are the most abundant aphid predators found in natural environment. Against aphids, the use of this semiochemical could certainly enhance the efficiency of natural enemies. Furthermore, the use of the chemical cue 3-Methyl-2-butenal could provide a novel approach to control aphids in field and greenhouse systems. [less ▲]

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See detailAcaricidal activities of Santolina Africana and Hertia Cheirifolia, two endemic plants of north Africa, on the two spotted spider mite (Tetranychus urticae)
Attia, Sabrine; Grissa, Kaouthar Lebdi; Le Goff, Guillaume et al

Poster (2011, May)

The two-spotted spider mite, Tetranychus urticae Koch, is a worldwide pest which feeds on a large variety of plant families. Because its resistance to acaricides is spreading rapidly, the development of ... [more ▼]

The two-spotted spider mite, Tetranychus urticae Koch, is a worldwide pest which feeds on a large variety of plant families. Because its resistance to acaricides is spreading rapidly, the development of new biological control tactics for population management is crucial. Plant extracts, such as Santolina africana and Hertia cheirifolia (Asteraceae), may represent viable alternatives, since they are currently considered to be minimumrisk pesticides. Although these two plants are known for their biocidal properties, the extract concentration that provides the most efficient control has not yet been precisely determined. In this study, we conducted a series of laboratory experiments to determine the susceptibility of adult females to different concentrations of S. africana and H. cheirifolia extract. These plants were steam-distilled and sprayed using a Potter spray tower. Mortality and fecundity were measured upon treatment with extract concentrations ranging from 0.07 to 6.75 mg/L. Female mortality increased with concentration, with LD50 values of 2.35 mg/L for S. africana and 3.43 mg/L for H. cheirifolia, respectively Reduced fecundity was previously observed at concentrations of 0.07, 0.09 and 0.29 mg/L .The chemical composition of the two oils were characterised by GC-MS. The most abundant components of the S. africana oil were terpinen-4-ol (44%), α- terpineol (11.31%) and borneol (6.73%). Camphor (15.11%), terpinen-4-ol (14.2%), α- terpineol (9.3%) were characteristic of the Hertia oil. [less ▲]

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See detailMicroorganisms from aphids attract hoverflies and enhance their efficacy
Leroy, Pascal ULg; Sabri, Ahmed ULg; Heuskin, Stéphanie ULg et al

Poster (2011, March 05)

Aphids are some of the most serious pests of crops worldwide, causing major yield and economic losses. They damage plants by feeding on the phloem sap, excreting copious amounts of honeydew and, in some ... [more ▼]

Aphids are some of the most serious pests of crops worldwide, causing major yield and economic losses. They damage plants by feeding on the phloem sap, excreting copious amounts of honeydew and, in some cases, vectoring plant diseases. Here, we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which is involved in the release of semiochemicals acting as a kairomone for aphid natural enemies. These semiochemicals were identified by Solid-Phase Microextraction (SPME) and Gas Chromatography-Mass Spectrometry (GC-MS). Our results show that this bacterium plays a key role in the interactions between aphids and natural enemies because it is the direct source of volatiles used by the aphidophagous hoverfly Episyrphus balteatus (De Geer) (Diptera: Syrphidae) to locate its aphid prey. Through wind-tunnel experiments, some specific semiochemicals produced by S. sciuri were identified as significant attractants and ovipositional stimulants. Also, assays under greenhouses and in potato fields have demonstrated that a culture medium containing the bacterium S. sciuri strongly attracts and induces the oviposition of hoverflies, enhancing their efficiency as biological control agents. The use of this no pathogenic bacterium could provide a very novel approach towards enhancing the efficacy of biological control agents to control aphids in field crops and greenhouse systems. [less ▲]

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See detailLutte contre les ravageurs des stocks de céréales et de légumineuses au Sénégal et en Afrique occidentale : synthèse bibliographique
Gueye, Momar Talla; Seck, Dogo; Wathelet, Jean-Paul ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(1), 183-194

Post-harvest losses of cereals and legumes are a major problem in Senegal and West Africa. The solutions to eliminate insects, major pests of stored products were mainly chemical. However, due to ... [more ▼]

Post-harvest losses of cereals and legumes are a major problem in Senegal and West Africa. The solutions to eliminate insects, major pests of stored products were mainly chemical. However, due to pollution associated with pesticides use, selection of resistant strains, environmental pollution, poisoning, the search for alternatives is needed. It is reported on different methods of protecting stocks performed alternatively or in combination with pesticides. The major pest species encountered, particularly Prostephanus truncatus (Horn), insect emerging in Senegal, could be controlled by alternative methods including specially the use of insecticide plants. Different aspects related to this alternative way to chemical pesticides are reviewed herein. Keywords. Cereals, pulses, post-harvest, control, pesticides, insecticide plants. [less ▲]

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See detailContrôle de Tetranychus urticae par les extraits de plantes en vergers d'agrumes
Attia, Sabrine; Lebdi Grissa, Kaouthar; Ghrabi-Gammar, Zeineb et al

in Entomologie Faunistique = Faunistic Entomology (2011), 63(4), 229-235

Tetranychus urticae est un acarien extrêmement polyphage, reconnu comme un ravageur majeur pour une grande quantité de plantes cultivées. Cet acarien cause d’importants dégâts sur agrumes et ... [more ▼]

Tetranychus urticae est un acarien extrêmement polyphage, reconnu comme un ravageur majeur pour une grande quantité de plantes cultivées. Cet acarien cause d’importants dégâts sur agrumes et principalement sur citronnier, se traduisant par de lourdes pertes économiques. L’objectif de ce travail est de mettre en évidence les propriétés acaricides d'extraits de plantes sur T. urticae. Douze extraits (macérats) issus de 12 plantes et deux acaricides de synthèse (Spirodiclofen et Fenbutatin oxyde) ont été choisis pour les essais en verger de citronniers. Ces résultats montrent que trois macérats extraits d’Allium sativum, A. cepa et Deverra scoparia présentent des propriétés acaricides comparables aux deux acaricides de synthèse qui sont les produits de référence. Cette efficacité perdure jusqu’à plus de 15 jours. Le macérat de D. scoparia a présenté l’activité acaricide la plus toxique et la plus rapide sur la population de T. urticae, 21 jours après traitement par rapport aux autres extraits et par rapport aux produits de référence. Ce travail permettra de mettre en place un programme de lutte intégrée visant le contrôle efficace des tétranyques s’attaquant aux citronniers. Les expériences en verger ont démontré que les extraits végétaux ont un effet acaricide pour T.urticae. [less ▲]

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See detailLe cloisonnement des interbuttes en culture de pomme de terre : essai réalisé en collaboration avec Bayer CropScience (Huldenberg 2011)
Olivier, Claire; Goffart, Jean-Pierre; Baets, D. et al

in Brochure du Centre Pilote Pomme de terre - FIWAP (2011), 9.5

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See detailEvaluation d’une méthode d’échantillonnage passif pour la mesure des monoterpènes dans l’air intérieur
Marlet, Christelle ULg; Lognay, Georges ULg; Plaisance, Hervé et al

in Pollution Atmosphérique (2011), 210

Monoterpenes are compounds naturally emitted by wooden materials. A preliminary study had demonstrated the occurrence of some monoterpenes in the timber frame constructions. Contrary to the active ... [more ▼]

Monoterpenes are compounds naturally emitted by wooden materials. A preliminary study had demonstrated the occurrence of some monoterpenes in the timber frame constructions. Contrary to the active sampling, the passive sampling with Radiello® device simplifies the sampling step that is an interest in indoor environment. However, the knowledge of the sampling rate is necessary for quantification via the passive samplers Radiello®. Radiello® sampler with Tenax TA cartridge was evaluated for the 4-h concentration measurements of nine monoterpenes (α-pinene, β-pinene, d-limonene, Δ3-carene, camphene, carvone, 1,8-cineole, linalool and p-cymene). The performance parameters of the method (calibration curve, trueness, repeatability, blank level, stability of samples) were estimated. The sampling rates were first evaluated under the standard conditions in an exposure chamber. The influences of three environmental factors (temperature (T), relative humidity (RH) and concentration level (C)) on the sampling rates were also evaluated following a full factorial design at two factor levels (low and high). The monoterpenes concentrations in the exposure chamber were followed by an active sampling on tube Tenax TA. For both sampling devices, analyses were realized by TD-GC-MS. The results of this study demonstrated that the Radiello® device is suitable for the measurement of 5 of 9 studied monoterpenes. The sampling rates were defined by an equation including two factors, temperature and relative humidity. Temperature is found to be the most important factor leading to variability of the all monoterpene sampling rates. An equation allowing to estimate the sampling rate was established for every studied compound. Measurements of monoterpenes with the Radiello® device were then carried out on new wooden houses and compared with measurements obtained by active sampling on Tenax TA tubes. [less ▲]

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See detailLes monoterpènes : sources et implications dans la qualité de l’air intérieur
Marlet, Christelle ULg; Lognay, Georges ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(4), 611-622

Terpenes are recurrent in indoor environments. Their sources, biogenic or anthropological origin, are very varied: plants, wooden building materials, household products and furnishings, paints, air ... [more ▼]

Terpenes are recurrent in indoor environments. Their sources, biogenic or anthropological origin, are very varied: plants, wooden building materials, household products and furnishings, paints, air fresheners, perfumed candles. However, in spite of their natural character, these compounds can have significant effects on occupant’s health. Indeed, some monoterpenes are recognized as irritating or allergenic. Furthermore, they react with the other molecules to form potentially more harmful secondary products such as formaldehyde. Numerous studies demonstrated that reactions between monoterpenes and ozone produced airborne particulate matter as well as secondary pollutants among which formaldehyde, acetaldehyde and acetone. However, few studies were realized in the indoor to demonstrate the terpenes and secondary pollutants evolution. The most frequently used technique for the monoterpenes analysis is the TD-GC-MS. The sampling mode depends on the sample introduction system, either the sampling on sorbent tube, or the sampling in a tank. The attraction for the wooden constructions and ecological materials leads to higher indoor monoterpenes concentrations. Does this occurrence have to arouse our interest? The present article has the objective to review the knowledge relative to terpenes, and more exactly on the monoterpenes sources in indoor and their implication in its quality. [less ▲]

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See detailAssessment of the acaricidal activity of several plant extracts on the phytophagous mite Tetranychus urticae (Tetranychidae) in Tunisian citrus orchards
Attia, Sabrine; Grissa, Kaouthar Lebdi; Zeineb, Ghrabi-Gammar et al

in Bulletin de la Société Royale Belge d'Entomologie = Bulletin van de Koninklijke Belgische Vereniging voor Entomologie (2011), 147(I-IV), 71-79

To develop sustainable pest control in Tunisian citrus orchards, the present work aimed to evalute the toxicity of 31 plant extracts obtained from Tunisia and two synthetic acaricides (spirodiclofen and ... [more ▼]

To develop sustainable pest control in Tunisian citrus orchards, the present work aimed to evalute the toxicity of 31 plant extracts obtained from Tunisia and two synthetic acaricides (spirodiclofen and fenbutatin oxide) on the phytophagous mite species Tetranychus urticae (Koch). [less ▲]

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See detailEssential Oil Composition of Ocimum basilicum L. and Ocimum gratissimum L. from Algeria
Brada, M.; Khelifa, L. H.; Achour, D. et al

in Journal of Essential Oil-Bearing Plants [=JEOBP] (2011), 14(6), 810-814

The constituents of essential oils isolated by hydrodistillation of the overground parts of Ocimum basilicum L. and Ocimum gratissimum L. from Algeria were examined by GC and GC-MS. A total of 46 and 43 ... [more ▼]

The constituents of essential oils isolated by hydrodistillation of the overground parts of Ocimum basilicum L. and Ocimum gratissimum L. from Algeria were examined by GC and GC-MS. A total of 46 and 43 components were identified accounting for 99.4 % and 97.7 % of O. basilicum and O. gratissimum oils, respectively. The oil of O. basilicum contained, as main components, linalool (44.7 %), linalyl acetate (14.0 %), 1,8-cineole (6.7 %), myrcene (5.6 %), α-terpineol (5.1 %), geranyl acetate (4.0 %), alloocimene (2.4 %), neryl acetate (2.4 %), elemol (2.1 %) and β-caryophyllene (1.3 %). Major compounds in the essential oil of O. gratissimum were eugenol (54.8 %), β-elemene (10.9 %), 1,8 cineole (4.1 %), α-humulene (3.8 %) linalool (2.1 %) and α-amorphene (2.1 %). [less ▲]

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See detailLeptin Reverts Pro-Apoptotic and Antiproliferative Effects of α-Linolenic Acids in BCR-ABL Positive Leukemic Cells: Involvement of PI3K Pathway
Beaulieu, Aurore ULg; Poncin, Géraldine ULg; Belaid-Choucair, Zakia et al

in PLoS ONE (2011), 6(10), 25651

It is suspected that bone marrow (BM) microenvironmental factors may influence the evolution of chronic myeloid leukaemia (CML). In this study, we postulated that adipocytes and lipids could be involved ... [more ▼]

It is suspected that bone marrow (BM) microenvironmental factors may influence the evolution of chronic myeloid leukaemia (CML). In this study, we postulated that adipocytes and lipids could be involved in the progression of CML. To test this hypothesis, adipocytes were co-cultured with two BCR-ABL positive cell lines (PCMDS and K562). T cell (Jurkat) and stroma cell (HS-5) lines were used as controls. In the second set of experiments, leukemic cell lines were treated with stearic, oleic, linoleic or α-linolenic acids in presence or absence of leptin. Survival, proliferation, leptin production, OB-R isoforms (OB-Ra and OB-Rb), phosphoinositide 3-kinase (PI3k) and BCL-2 expression have been tested after 24h, 48h and 72h of treatment. Our results showed that adipocytes induced a decrease of CML proliferation and an increase in lipid accumulation in leukemic cells. In addition, CML cell lines induced adipocytes cell death. Chromatography analysis showed that BM microenvironment cells were full of saturated (SFA) and monounsaturated (MUFA) fatty acids, fatty acids that protect tumor cells against external agents. Stearic acid increased Bcl-2 expression in PCMDS, whereas oleic and linoleic acids had no effects. In contrast, α-linolenic acid decreased the proliferation and the survival of CML cell lines as well as BCL-2 and OB-R expression. The effect of α-linolenic acids seemed to be due to PI3K pathway and Bcl-2 inhibition. Leptin production was detected in the co-culture medium. In the presence of leptin, the effect of α-linolenic acid on proliferation, survival, OB-R and BCl-2 expression was reduced.</p> [less ▲]

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See detailDoes Tribolium brevicornis cuticular chemistry deter cannibalism and predation of pupae?
Alabi, Taoffic; Dean, Jennifer; Michaud, Jean-Pierre et al

in Journal of Insect Science [=JIS] (2011), 11

The cuticular hydrocarbons of insects are species-specific and often function as semiochemicals. The activity of Tribolium brevicornis cuticular hydrocarbons as feeding deterrents that ostensibly function ... [more ▼]

The cuticular hydrocarbons of insects are species-specific and often function as semiochemicals. The activity of Tribolium brevicornis cuticular hydrocarbons as feeding deterrents that ostensibly function to prevent pupal cannibalism and predation was evaluated. The cuticular hydrocarbons of T. brevicornis pupae were characterized and flour disk bioassays conducted with individual and combined extract components incorporated into artificial diets on which Tribolium adults fed for six days. Feeding by T. brevicornis and T. castaneum on flour disks containing cuticular extracts of T. brevicornis pupae resulted in reduced consumption and weight loss relative to feeding on control flour disks. In both cases, feeding deterrence indices exceeded 80% suggesting that T. brevicornis cuticular hydrocarbons could function to deter cannibalism and predation of pupae by larvae and adult beetles. Sixteen different cuticular hydrocarbons were identified in T. brevicornis pupal extracts. Eight of the commercially available linear alkanes were tested individually in feeding trials with eight Tribolium species. One compound (C28) significantly reduced the amount of food consumed by three species compared to control disks, whereas the compounds C25, C26, and C27elicited increased feeding in some species. Four other compounds had no effect on consumption for any species. When four hydrocarbon mixtures were tested for synergistic deterrence on T. brevicornis and T. castaneum, none significantly influenced consumption. Our results indicate that the cuticular chemistry of T. brevicornis pupae could serve to deter predation by conspecific and congeneric beetles. [less ▲]

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