References of "Lognay, Georges"
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See detailDo root-emitted volatile organic compounds attract wireworms?
Barsics, Fanny ULg; Latine, Rémi ULg; Gfeller, Aurélie ULg et al

in Communications in Agricultural and Applied Biological Sciences (2012), 77(3), 561-567

Wireworms are the soil dwelling larvae of click beetles (Coleoptera: Elateridae). Their importance as crop pests increases since the efficient chemical means to control them cannot be considered anymore ... [more ▼]

Wireworms are the soil dwelling larvae of click beetles (Coleoptera: Elateridae). Their importance as crop pests increases since the efficient chemical means to control them cannot be considered anymore. Therefore, many integrated pest management strategies have been investigated in the past few years. Most of them rely on the understanding of the ecology of the click beetles during their whole life cycle. We focus our work on the chemical ecology of wireworms, more precisely on the root-emitted volatile organic compounds (VOCs) that might intervene in the food-searching process of the larvae by helping them to find a suitable host-plant or by acting as key factors in the belowground defence mechanism of the plant. Here, we present our first results of dual-choice orientation tests in olfactometric pipes. Wireworms (Agriotes sordidus Illiger) were submitted individually to a variety of olfactory baits ranging from entire barley roots (Hordeum vulgare L. var. Quench) to isolated VOCs identified as part of the emitting profile. The latter was described thanks to HS-SPME samplings and GC-MS analysis, for roots grown in the exact same conditions as for the olfactometric experimentations with entire roots. Most of the experimentations gave significant results. When confronted to volatiles emitted by entire roots, wireworms significantly orientated towards the bait (χ²-goodness-of-fit test, χ²=8, P-value=0.005). This result allowed us to follow up with the same device and to progressively vary the nature of the baits. Our protocol should be used for other plant-wireworm species combinations. Our results should be taken into account in varietal selection, in crop rotation, or in trapping systems aiming at the reduction of the populations of wireworms. [less ▲]

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See detailAcaricidal activities of Santolina africana and Hertia cheirifolia essential oils against the two-spotted spidermite (Tetranychus urticae)
Attia, Sabrine; Grissa, K.L.; Mailleux, A-C et al

in Pest Management Science (2012)

BACKGROUND: Many plant essential oils show a broad spectrum of activity against pests. This study investigated the effects of two essential oils on Tetranychus urticae, one of the most serious pests in ... [more ▼]

BACKGROUND: Many plant essential oils show a broad spectrum of activity against pests. This study investigated the effects of two essential oils on Tetranychus urticae, one of the most serious pests in the world. RESULTS: The chemical composition of the two oils was characterised by GC-MS. The most abundant component in the Santolina africana (Jord. & Fourr) oil was terpinen-4-ol (54.96%), while thymol (61%) was prevalent in the Hertia cheirifolia (L.) oil. Mortality and fecundity were measured upon treatment with oil concentrations ranging from 0.07 to 6.75 mg L-1 with a Potter spray tower.Mite mortality increased with oil concentration, with LC50 values of 2.35 mg L-1 for S. africana and 3.43mg L-1 for H. cheirifolia respectively. For both oils, a reduction in fecundity was observed at concentrations of 0.07, 0.09 and 0.29mg L-1. Artificial blends of constituents of oils were also prepared and tested with individual constituents missing from the mixture. The results showed that the presence of all constituents was necessary to equal the toxicity of the two natural oils. CONCLUSION: S. africana and H. cheirifolia oils can provide valuable acaricide activitywith significantly lower LC50 values. Thus, these oils cause important mortality and reduce the number of eggs laid by females. [less ▲]

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See detailVariations in the essential oils from ylang-ylang (Cananga odorata [Lam.] Hook f. & Thomson forma genuina) in the Western Indian Ocean islands
Benini, Céline; Ringuet, Mélanie; Wathelet, Jean-Paul ULg et al

in Flavour and Fragrance Journal (2012), 27(5), 356-366

Ylang-ylang essential oil is an important rawmaterial for the fragrance industry. Despite its economic importance, to the best of our knowledge, no study has yet been undertaken to assess the chemical ... [more ▼]

Ylang-ylang essential oil is an important rawmaterial for the fragrance industry. Despite its economic importance, to the best of our knowledge, no study has yet been undertaken to assess the chemical polymorphism of the different production areas. This underestimated variability is an interesting source of raw material for perfumers. That is why the variation in the chemical composition of four fractions of the essential oils extracted from Cananga odorata, grown in four locations Grande Comore, Mayotte, Nossi Bé and Ambanja, was studied. A total of 119 compounds, representing 85.7–96.4%of the total essential oil composition, were identified using gas chromatography–mass spectrometry and quantified by gas chromatography with a flame ionization detector. Thirty-two compounds previously unreported in ylang-ylang essential oil were identified. The distinction between the Comoros and Madagascar groups wasmade on the basis of the chemical classes. It was possible to significantly distinguish the Grande Comore and Mayotte essential oil samples, as well as the Ambanja and Nossi Bé essential oil samples, on the basis of their main compounds. The aromatic compounds profile for the origin of each essential oil fraction was established. <br />Regression trees were built, allowing the provenance of the essential oils prepared at the laboratory level to be easily differentiated on the basis of a limited number of major compounds. [less ▲]

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See detailChemical Composition and Antioxidant Activity of Essential Oil of Ocimum basilicum Leaves from the Northern Region of Algeria
Hadj Khelifa, L.; Brada, Moussa; Brahmi, F. et al

in Topclass Journal of Herbal Medicine (2012), 1(2), 53-58

Ocimum basilicum essential oil (Algerian species), which is extracted from dried leaves with an output of 1.98 ± 0.01%, is yellow pale. Its chemical composition has been investigated by GC/MS and GC/FID ... [more ▼]

Ocimum basilicum essential oil (Algerian species), which is extracted from dried leaves with an output of 1.98 ± 0.01%, is yellow pale. Its chemical composition has been investigated by GC/MS and GC/FID. Fourty compounds have been identified accounting for 97.4%. The major compounds were: Linalool (32.83%), linalyl acetate (16%), elemol (7.44%), geranyl acetate (6.18%), myrcene (6.12%), allo-ocimene (5.02%), α-terpineol (4.9%), (E)-β-ocimene (3.68%) and neryl acetate (3.45%). O. basilicum essential oil was screened for its in vitro antioxidant activity using DPPH assay. The results showed that the concentration of the essential oil needed to scavenge 50% of DPPH, was 83.54 mg/ml lower than that of vitamin E (22.0 mg/ml) and therefore acts as a natural antioxidant agent. [less ▲]

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See detailFast-GC quantification of harmonine, the major defense alkaloid of the multicolored asian ladybird Harmonia axyridis (Pallas)
Fischer, Christophe ULg; Laurent, P; Heuskin, Stéphanie ULg et al

in American Journal of Analytical Chemistry (2012), 3

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See detailThe Essential Oils of Origanum majorana L. and Origanum floribundum Munby in Algeria
Brada, Moussa; Saadi, Abdelkader; Wathelet, Jean-Paul ULg et al

in Journal of Essential Oil-Bearing Plants [=JEOBP] (2012), 15(3), 497-502

The constituents of essential oils isolated by hydrodistillation of the overground parts of Origanum majorana and Origanum floribundum from Algeria were examined by GC and GC-MS. A total of thirty eight ... [more ▼]

The constituents of essential oils isolated by hydrodistillation of the overground parts of Origanum majorana and Origanum floribundum from Algeria were examined by GC and GC-MS. A total of thirty eight and thirty seven components were identified accounting for 93.3 % and 88.9 %, respectively, of the oils of O. majorana and O. floribundum. The oil of O. majorana (yield: 1.2 %) contained, as main components, β-caryophyllene (26.0 %), α-terpinolene (14.7 %), γ-terpinene (10.9 %) and sabinene (9.5 %). Major compounds in the volatile oil of O. floribundum (yield: 1.6 %) were γ-terpinene (34.1 %), p-cymene(27.6 %) and carvacrol (9.6 %). [less ▲]

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See detailEfficacy of powdered maize cobs against the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae) in stored maize in Senegal
Gueye, Talla Momar; Cissokho, Papa Seyni; Goergen, Georg et al

in International Journal of Tropical Insect Science (2012)

Powdered maize cobs were tested as an alternative for pesticide use in stored maize. Five doses (2, 4, 6, 8 and 10 g/250 g seed) of powdered maize cobs applied at particle sizes of 1.4 and 0.4mm diameter ... [more ▼]

Powdered maize cobs were tested as an alternative for pesticide use in stored maize. Five doses (2, 4, 6, 8 and 10 g/250 g seed) of powdered maize cobs applied at particle sizes of 1.4 and 0.4mm diameter were compared with actellic powder against Sitophilus zeamais Motschulsky for 120 days. Mortality and survival data showed that cob powders did not act as fumigant but exerted a potent inhibition of progeny on direct contact with S. zeamais adults. The particle size of powdered cobs had no effect on maize damage and losses. At doses equal to or higher than 6 g powdered maize cobs/250 g grain maize, i.e. 2.4% (w/w), damage to grain was ,5% and weight losses ,1%. The protection offered at the highest dose was comparable to the pesticide control. The use of powdered maize cobs is discussed as a natural alternative to synthetic pesticides for protection of maize against S. zeamais. [less ▲]

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See detailComment les insectes communiquent-ils au sein de l’ «écosystème-cadavre» ? L’écologie chimique des insectes nécrophages et nécrophiles
Dekeirsschieter, Jessica ULg; Verheggen, François ULg; Frederickx, Christine ULg et al

in Faunistic Entomology - Entomologie Faunistique (2012), 65

L’entomologie forensique est une discipline des sciences forensiques qui étudie les insectes et d’autres arthropodes dans un contexte médico-légal. Les insectes nécrophages et nécrophiles, principalement ... [more ▼]

L’entomologie forensique est une discipline des sciences forensiques qui étudie les insectes et d’autres arthropodes dans un contexte médico-légal. Les insectes nécrophages et nécrophiles, principalement des Diptères et des Coléoptères, sont fréquemment retrouvés au sein de l’écosystème-cadavre. Pour ces insectes, le cadavre est une ressource éphémère très riche qu’ils vont coloniser de manière plus ou moins prévisible. L’entomofaune des cadavres seraient attirées par les odeurs cadavériques émises par le corps en décomposition. A l’heure actuelle, la thanatochimie est encore peu étudiée et l’information disponible concernant les COVs émis après la mort est limitée. Grâce à l’utilisation des méthodes de chimie analytique (TDS)GC-MS, GCxGC-TOF-MS), la signature olfactive d’un cadavre peut être étudiée au cours du processus de décomposition. L’ « odeur de la mort » est constituée par un mélange de plus de cent composés organiques volatils qui évoluent au cours de la décomposition. Cependant, les sémiochimiques qui sont réellement attractifs pour les insectes nécrophages et/ou nécrophiles ne sont pas encore clairement identifiés. Les espèces pionnières pourraient être attirées par des COVs cadavériques. Toutefois, les espèces plus tardives pourraient aussi être attirées par d’autres types de sémiochimiques produits par les insectes sarcosaprophages eux-mêmes (par exemple : des asticots, des insectes nécrophages). Plusieurs techniques d’écologie chimique peuvent être utiles en vue d’investiguer le rôle des sémiochimiques cadavériques dans le comportement des insectes sarcosaprophages. Une meilleure compréhension de l’écologie chimique des insectes nécrophages/nécrophiles et la thanatochimie pourraient avoir de nombreuses applications en science forensique et plus particulièrement en entomologie forensique. [less ▲]

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See detailE-b-farnesene synergizes the influence of an insecticide to improve control of cabbage aphids in China
Cui, L.L; Dong, J.; Francis, Frédéric ULg et al

in Crop Protection (2012)

Extensive use of pesticides to control insect pests can have negative effects on the environment, natural enemies and food safety. The aphid alarm pheromone, E-b-farnesene (Ebf), appears to hold strong ... [more ▼]

Extensive use of pesticides to control insect pests can have negative effects on the environment, natural enemies and food safety. The aphid alarm pheromone, E-b-farnesene (Ebf), appears to hold strong potential for controlling a wide variety of aphid pests. To understand the control potential of Ebf, we used field experiments in a factorial design to test its influence and that of the insecticide imidacloprid on populations of aphids Lipaphis erysimi (Kaltenbach) and Myzus persicae (Sulzer) on Chinese cabbage, Brassica rapa pekinensis (Brassicales: Brassicaceae). Our results showed imidacloprid treatment alone can significantly decrease aphid populations, and that combining insecticide with Ebf further reduced numbers of apterous aphids at distances of 5 m from pheromone emitters in two years of our experiments. Our results demonstrate that imidacloprid can be effective in reducing the abundance of aphids in Chinese cabbage fields, but the degree of control can be even stronger in the presence of Ebf. [less ▲]

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See detailRole of long-chain hydrocarbons in the aggregation behaviour of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
Durieux, Delphine ULg; Fischer, Christophe ULg; Brostaux, Yves ULg et al

in Journal of Insect Physiology (2012)

The multicoloured Asian ladybeetles, Harmonia axyridis (Pallas), form large aggregations inside dwellings to survive cold winters, causing annoyances to householders from their number and sometimes the ... [more ▼]

The multicoloured Asian ladybeetles, Harmonia axyridis (Pallas), form large aggregations inside dwellings to survive cold winters, causing annoyances to householders from their number and sometimes the induction of allergic reactions. Migratory flight and macrosite choice of this species is well documented. H. axyridis shows a hypsotactic behaviour and a clear preference for contrasting visual elements. However, how the microsite is selected remains undocumented, although a better understanding of the implicated factors could lead to the development of new control methods for this pest. In this work, we have hypothesized that non-volatile compounds are involved in the microsite choice and the aggregation process of this beetle. Long chain hydrocarbons were identified inside aggregation sites, comprising saturated and unsaturated homologues. An aggregation bioassay was then conducted on overwintering individuals, highlighting the retention capacity of the previously cited compounds on the tested ladybeetles. Additional investigations have shown that H. axyridis males and females, originating from overwintering sites, deposit a similar blend of molecules while walking. A Y-shaped tube assay revealed that this blend is used by male and female congeners as cue, allowing individuals to orientate towards the treated side of the olfactometer. These results suggest the use of two different blends of long chain hydrocarbons by H. axyridis during its aggregative period, the first one to lead conspecifics towards aggregation sites (microsites) and the second to ensure the cohesion of the aggregation. These findings support the potential use of these blends, in association with volatiles, in the design of traps in order to control infestations of this species in dwellings. [less ▲]

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See detailThe functional significance of E-b-Farnesene: Does it influence the populations of aphid natural enemies in the fields?
Cui, L-L; Francis, Frédéric ULg; Heuskin, Stéphanie ULg et al

in Biological Control (2012)

Aphids cause much damage to Chinese cabbage in northern China. Over reliance on pesticides have large environmental and human health costs that compel researchers to seek alternative management tactics ... [more ▼]

Aphids cause much damage to Chinese cabbage in northern China. Over reliance on pesticides have large environmental and human health costs that compel researchers to seek alternative management tactics for aphid control. The component of aphid alarm pheromone, E-b-Farnesene (EbF), extracted from Matricaria chamomilla L., which attracts natural enemies in the laboratory, may have significant implications for the design of cabbage aphid control strategies. The purpose of this paper is to understand the effects of EbF on natural enemies to cabbage aphid control in Chinese cabbage fields. Ladybeetles on Chinese cabbage leaves in EbF released plots and Aphidiidae in EbF released yellow traps were significantly higher than those of in controls. No significant differences were detected in the interactions of different treatments and the two years for all natural enemies. More important, lower aphid densities were found in EbF released plots. Our results suggested that the EbF extracted from M. chamomilla L. could attract natural enemies to reduce cabbage aphids in the Chinese cabbage fields. [less ▲]

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See detailStudy of the factors involved in the aggregation of Harmonia axyridis Pallas (Coleoptera : Coccinellidae)
Durieux, Delphine ULg; Fischer, Christophe ULg; Deneubourg, Jean-Louis et al

in Communications in Agricultural and Applied Biological Sciences (2012), 77(1), 101-104

The aggregative behaviour of the multicoloured Asian ladybeetle, Harmonia axyridis Pallas, during winters, is still misunderstood. Our study was focused on the chemical and physical factors involved in ... [more ▼]

The aggregative behaviour of the multicoloured Asian ladybeetle, Harmonia axyridis Pallas, during winters, is still misunderstood. Our study was focused on the chemical and physical factors involved in the selection of its aggregation sites. Chemical and behavioural analyses highlighted that long-chain hydrocarbons lead congeners towards aggregations and ensure the cohesion of the cluster. On the other hand, we investigated the influence of (1) the density of individuals and (2) the quality of available shelters on H. axyridis decision to settle and aggregate under shelters. A binary choice experiment conducted in laboratory highlighted a permanent aggregative behaviour of H. axyridis, even during non-wintering conditions, and the existence of social interactions between individuals. [less ▲]

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See detailComposition of the Essential Oil of Leaves and Berries of Algerian Myrtle (Myrtus comunis L.)
Brada, M.; Tabli, N.; Boutopumi, H. et al

in Journal of Essential Oil Research (2012)

Myrtus communis L. essential oils were obtained by hydrodistillation, and the yields were 0.3% (w/w) and 0.1% for leaves and berries, respectively. Using GC and GC/ MS techniques, twenty five components ... [more ▼]

Myrtus communis L. essential oils were obtained by hydrodistillation, and the yields were 0.3% (w/w) and 0.1% for leaves and berries, respectively. Using GC and GC/ MS techniques, twenty five components were identified in berry oil representing 89.5% of the oil composition. Linalool was the major compound in berry oil (36.2%) followed by estragole (18.4%) and 1,8-cineole (11.4%). Leaf oil was composed of 28 compounds representing 95.4% of the total composition of the oil. α-pinene was the major constituent of leaf oil at concentration of (46.9%), followed by 1,8-cineole (25.2%). The two Algerian oils were characterized by the lack of myrtenyl acetate. [less ▲]

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See detailInsecticidal activity of Boscia senegalensis (Pers.) Lam ex Poir. on Caryedon serratus (Ol.) pest of stored groundnuts
Gueye, Momar Talla; Seck, Dogo; Ba, Seynabou et al

in African Journal of Agricultural Research (2011), 6(30), 6348-6353

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See detailLes volatils racinaires de l’orge : un langage souterrain ?
Barsics, Fanny ULg; Gfeller, Aurélie ULg; Fauconnier, Marie-Laure ULg et al

Scientific conference (2011, October 13)

Cette présentation résume les avancées du projet Rhizovol après une année de travaux de recherche.

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See detailLes larves de taupins sont attirées par différentes sources de volatils racinaires
Barsics, Fanny ULg; Latine, Rémi ULg; Haubruge, Eric ULg et al

Poster (2011, October 13)

Grâce à des tests olfactométriques, nous voulons mettre en évidence la capacité de certains COVs d’origine racinaire à attirer ou repousser les larves de taupins. Nous montrons ici les premiers résultats ... [more ▼]

Grâce à des tests olfactométriques, nous voulons mettre en évidence la capacité de certains COVs d’origine racinaire à attirer ou repousser les larves de taupins. Nous montrons ici les premiers résultats obtenus grâce à des olfactomètres tubulaires, soit l’attraction par des COVs issus de racines hachées et l’attraction par le 2-pentylfuran, volatil contenu dans les racines d’orge. [less ▲]

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See detailChemical composition and acaricidal properties of Devera scoparia essential oil (Araliales: Apiaceae) and blends of its major constituents against Tetranychus urticae (Acari: Tetranychidae)
Attia, Sabrine; Grissa, K. L.; Lognay, Georges ULg et al

in Journal of Economic Entomology (2011), 104(4), 1220-1228

The essential oil of Deverra scoparia Coss. & Durieu was investigated for its acaricidal activity against the worldwide pest twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). The ... [more ▼]

The essential oil of Deverra scoparia Coss. & Durieu was investigated for its acaricidal activity against the worldwide pest twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). The essential oil was analyzed by fast gas chromatography (GC) and GC-mass spectrometry. The activities of its individual and blended constituents were determined. Our study showed that female mortality increased with increasing D. scoparia oil concentrations, with LD50 and LD90 values at 1.79 and 3.2 mg liter 1, respectively. A reduction in fecundity had already been observed for concentrations of 0.064, 0.08, and 0.26 mg liter 1 D. scoparia essential oil. Ten major components, comprising 98.52% of the total weight, were identiÞed; -pinene was the most abundant constituent (31.95%) followed by sabinene (17.24%) and 3-carene (16.85%). The 10 major constituents of D. scoparia oil were individually tested against T. urticae females. The most potent toxicity was found with -pinene, 3-carene, and terpinen-4-ol. The presence of all constituents together in the artiÞcial mixture caused a signiÞcant decrease in the number of eggs laid by females, at 0.26mgliter 1 (11 eggs), compared with the control (50 eggs). The toxicity of blends of selected constituents indicated that the presence of all constituents was necessary to reproduce the toxicity level of the natural oil. [less ▲]

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See detailAnt-aphid mutualism - A question of microorganisms?
Fischer, Christophe ULg; Patris, Geoffrey; Duriaux, Adrien ULg et al

Poster (2011, September)

It is now long known that some ant and aphid species can present a mutualistic relationship, ants using aphid honeydew as sugar source and in exchange providing the aphid colony cleaning and protection ... [more ▼]

It is now long known that some ant and aphid species can present a mutualistic relationship, ants using aphid honeydew as sugar source and in exchange providing the aphid colony cleaning and protection. From a behavioral point of view, this phenomenon has been well studied, but its chemistry and semiochemical mechanisms are still largely unknown. This study aims to identify semiochemicals involved in the establishment of this relation and their sources, using both chemical and behavioral methods. Bioassays revealed that the greatest part of ant attraction toward aphid colonies is due to honeydew volatile compounds; enabling ant scouts to find more quickly aphid colonies and distantly recognize myrmecophilous species. Many of those VOCs seeming to have microbial origins, the main honeydew microorganisms have been isolated and their roles in VOCs production and ant attraction have been investigated. [less ▲]

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