References of "Francis, Frédéric"
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See detailPredatory hoverflies select their oviposition site according to aphid host plant and aphid species
Almohamad, Raki; Verheggen, François ULg; Francis, Frédéric ULg et al

in Entomologia Experimentalis et Applicata (2007), 125(1), 13-21

The hoverfly Episyrphus balteatus De Geer (Diptera: Syrphidae) is an abundant and efficient aphid-specific predator. Several aphidophagous parasitoids and predators are known to respond positively to ... [more ▼]

The hoverfly Episyrphus balteatus De Geer (Diptera: Syrphidae) is an abundant and efficient aphid-specific predator. Several aphidophagous parasitoids and predators are known to respond positively to aphid-infested plants. Semiochemicals from the latter association usually mediate predator/parasitoid foraging behavior toward sites appropriate for offspring fitness. In this study, we investigated the effect of aphid host plant and aphid species on foraging and oviposition behavior of E. balteatus. Behavioral observations were conducted using the Noldus Observer v. 5.0, which allows observed insect behavior to be subdivided into different stages. Additionally, the influence of aphid species and aphid host plant on offspring fitness was tested in a second set of experiments. Acyrthosiphon pisum Harris and Megoura viciae Buckton were equally attractive for E. balteatus whereas Aphis fabae Scopoli (all Homoptera: Aphididae) were less attractive. These results were correlated with (i) the number of eggs laid, which was significantly higher for the two first aphid species, and (ii) the fitness of hoverfly larvae, pupae, and adults. Two solanaceous plant species, Solanum nigrum L. and Solanum tuberosum L. (Solanaceae), which were infested with Myzus persicae Sulzer (Homoptera: Aphididae), were also compared using the same approach. Discrimination between these two M. persicae host plants was observed, with S. tuberosum being preferred as an oviposition site by the predatory hoverfly. Larval and adult fitness was correlated with the behavioral observations. Our results demonstrated the importance of the prey-host plant association on the choice of the oviposition site by an aphid predator, which is here shown to be related to offspring fitness. [less ▲]

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See detailResponse and genetic analysis of malathion-specific resistant Tribolium castaneum (Herbst) in relation to population density
Assie, L. K.; Francis, Frédéric ULg; Gengler, Nicolas ULg et al

in Journal of Stored Products Research (2007), 43(1), 33-44

Extensive use of malathion for pest control on stored cereals has resulted in worldwide resistance in red flour beetles, Tribolium castaneum. In this paper we investigate population density effects on the ... [more ▼]

Extensive use of malathion for pest control on stored cereals has resulted in worldwide resistance in red flour beetles, Tribolium castaneum. In this paper we investigate population density effects on the malathionspecific resistance in PRm, a strain from the Philippines, in an integrated resistance management framework. Two populations of malathion-specific resistant (PRm) and a malathion- susceptible strain of T castanewn were bred at different densities: low (4 adults/g) and high (12 adults/g) density on wheat plus brewer's yeast in the laboratory. After eight generations, slopes of probit regression lines and LC50 values were used to monitor the effect of insect rearing density on the progression of malathion-specific resistance. The LC50 of the malathion- susceptible strain (Asm) did not change significantly during selection while LC(50)s varied for both the high-density and low-density lines of PRm, the LC50 of malathion ranged from 27.51 to 34.06 and from 21.14 to 29.39 Vg malathion cm(-2) for high and low density, respectively. More than 33 generations were required to achieve a 10-fold increase of resistance for the low-density line compared to only 17 generations for the high-density line. Calculations from published formulae suggested that the malathion-specific resistance of both high- and low-density lines was under monofactorial control, with complete dominance. The data showed that environmental factors such as population density differences in insect rearing and development may influence the heritability of resistance. Furthermore, the variability in results published worldwide on resistance emphasises the need to standardize test conditions across laboratories. (c) 2005 Published by Elsevier Ltd. [less ▲]

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See detailHow does the age of hoverfly females affect their reproduction?
Almohamad, Raki; Verheggen, François ULg; Francis, Frédéric ULg et al

Conference (2007)

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See detailIntraguild interactions of aphidophagous predators in fields: effect of Coccinella septempunctata and Episyrphus balteatus occurrence on aphid infested plants.
Alhmedi, Ammar; Francis, Frédéric ULg; Bodson, Bernard ULg et al

in Communications in Agricultural and Applied Biological Sciences (2007), 72(3), 381-90

Intraguild relations between beneficial insects have become a major research topic in biological pest control. In order to understand the intraguild competitions between aphidophagous populations in ... [more ▼]

Intraguild relations between beneficial insects have become a major research topic in biological pest control. In order to understand the intraguild competitions between aphidophagous populations in natural conditions, a field experiment was carried out in the experimental farm of the Gembloux Agricultural University. As biological control of pests involve a community of diverse natural enemies, this experiment firstly aimed to assess the aphidophagous predator diversity and abundance in green pea (Pisum sativum) field and secondly to investigate the impact of the large natural occurrence of C. septempunctata on the aphidophagous beneficial dispersion and efficiency as aphid biological control agents in pea field. Visual observations were weekly performed throughout the 2006 growing season. The pea aphids were attacked by several predatory groups, mainly ladybird beetles and hoverflies. Higher densities of ladybirds and hoverflies were recorded in the beginning of July, associated with an aphid occurrence peak. Using net cage system in the field, the particular intraguild relations between added C. septempunctata or E. balteatus and the natural beneficial arrivals and dispersion were observed. The E. batteatus (eggs and larvae) presence inhibited other aphidophagous predators presence on the aphid infested plants. Lower abundance of E. balteatus was observed on aphid infested plants already colonised by C. septempunctata. To explore more accurately the oviposition and predation behaviours of ladybirds and hoverflies and to determine the chemical factors that could influence these behaviours, current researches are performed in laboratory and will be discussed to promote efficient biological control of aphids by natural enemies. [less ▲]

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See detailEffect of a fungal lectin from Xerocomus chrysenteron (XCL) on the biological parameters of aphids.
Jaber, Karimi; Francis, Frédéric ULg; Paquereau, Laurent et al

in Communications in Agricultural and Applied Biological Sciences (2007), 72(3), 629-38

Aphids are important pests of crop plants in Europe. Increasing resistance of aphids to insecticides and their side effects on the environment and non target organism's including human's stimulated ... [more ▼]

Aphids are important pests of crop plants in Europe. Increasing resistance of aphids to insecticides and their side effects on the environment and non target organism's including human's stimulated research on alterative methods of aphid control, including the use of entomotoxic proteins. Lectins are carbohydrate binding proteins that are widely distributed in nature; they have been isolated from microorganisms, fungi, plants and animals. Several of these proteins were tested for their potential biocide effect on plenty of pests. A fungal lectin, namely Xerocomus Chrysenteron lectin (XCL) was previously purified and was shown to be toxic for several pests including aphids. XCL was clearly the most toxic lectin against M. persicae. In this work, bioassays using artificial diets incorporating a broad range of XCL concentrations (from 10 microg x ml(-1) to 5000 microg x ml(-1)) were developed to assess the negative effects of XCL on the biological parameters (development duration, weight and fecundity) of M. persicae a polyphagous aphid found on more than 400 host plant species and transmitting more than 100 viral diseases. A significant mortality of aphids was observed, corresponding to the LC50 and LC90 of 0, 46 and 6, 02 mg/ml respectively after 24hrs. Significant differences of M. persicae weight, development duration and fecundity (P < 0.05) was observed between the tested XCL concentrations. Conavalia ensifomris lectin (ConA) was included as lectin reference on the bioassay experiments and was shown to be less toxic and induced lower negative changes in M. persicae biological parameters when compared with XCL. [less ▲]

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See detailPhysicochemical and functional properties of typical tunisian drink: date palm sap (Phoenix dactylifera L.)
Ben Thabet, Imène; Attia, Hamadi; Besbes, Souhail et al

in Food Biophysics (2007), 2(2), 76-82

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See detailAphidophagous Guilds On Nettle (Urtica Dioica) Strips Close To Fields Of Green Pea, Rape And Wheat
Alhmedi, A.; Haubruge, Eric ULg; Bodson, Bernard ULg et al

in Insect Science (2007), 14(5), 419-424

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See detailHow does the age of hoverfly females affect their reproduction?
Almohamad, Raki; Verheggen, François ULg; Francis, Frédéric ULg et al

in Communications in Agricultural and Applied Biological Sciences (2007), 72(3),

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See detailÉvaluation de la diversité des pucerons et de leurs ennemies en grandes cultures à proximité de parcelles d’orties
Alhmedi, Ammar; Francis, Frédéric ULg; Bodson, Bernard ULg et al

in Notes Fauniques de Gembloux (2007), 60

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See detailMolecular cloning and functional expression of a new aphid isoprenyl diphosphate synthase
Vandermoten, Sophie ULg; Beliveau, Catherine; Sen, Stephanie et al

Poster (2006, December 18)

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See detailMolecular cloning and functional expression of a new aphid isoprenyl diphosphate synthase
Vandermoten, Sophie ULg; Beliveau, C.; Sen, S. et al

in Archives Internationales de Physiologie et de Biochimie (2006, December), 190

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