References of "Francis, Frédéric"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailSemiochemicals of Rhagoletis Fruit Flies: Potential for Integrated Pest Management
Sarles, Landry ULg; Verhaeghe, Agnès; Francis, Frédéric ULg et al

in Crop Protection (in press)

Worldwide economic losses associated with Rhagoletis fruit flies (Diptera: Tephritidae) require an effective means of control. Most conventional insecticides used to control fruit flies have been banned ... [more ▼]

Worldwide economic losses associated with Rhagoletis fruit flies (Diptera: Tephritidae) require an effective means of control. Most conventional insecticides used to control fruit flies have been banned, and fruit producers are seeking new economical fruit fly control options. Bait stations can be a suitable alternative, provided they are affordable, effective and pest-specific. Semiochemicals are important for fruit flies to locate their host fruit and to reproduce. They could therefore be good candidates to improve existing bait stations. In this literature review, we summarize the available data on Rhagoletis semiochemicals, including the pheromones and allelochemicals used for host location. Then, we present some field applications of semiochemicals that have been successful at Rhagoletis fly control and discuss potential semiochemical-based control strategies. [less ▲]

Detailed reference viewed: 13 (1 ULg)
Full Text
Peer Reviewed
See detailDo wildflower strips favor insect pest populations at field margins ?
Hatt, Séverin ULg; Uyttenbroeck, Roel ULg; Chevalier Mendes Lopes, Thomas ULg et al

in Scientific Papers. Series A. Agronomy (in press)

Reducing pesticide use is one the major issues of today’s agriculture. Among other possibilities, attracting and conserving pest natural enemies in agricultural landscapes by providing them habitats is ... [more ▼]

Reducing pesticide use is one the major issues of today’s agriculture. Among other possibilities, attracting and conserving pest natural enemies in agricultural landscapes by providing them habitats is promising. Wildflower strips (WFS) sown at field margins are one of these potential habitats. They are known to attract and conserve a large diversity of insects, as they provide them food resources such as pollen and nectar, as well as shelter and overwintering sites. However, the risk of attracting insect pests at field margins may represent an obstacle to their adoption by farmers. Conversely, it would be interesting if such WFS could play the role of pest trap crops. In an experimental field sown with WFS intercropped with oilseed rape (OSR) (Brassica napus L.), its coleopteran pests were trapped in both WFS and OSR using yellow pan traps between April and June 2014. More than 130 000 Meligethes spp., Ceutorhynchus spp. and Psylliodes chrysocephalla (L.) adults were trapped. Meligethes spp., Ceutorhynchus spp. were significantly more abundant in the OSR compared with WFS when adults emerged and populations reached their abundance peak. Before and between these periods, the few adults trapped were significantly more abundant in the WFS compared with the OSR. Concerning P. chrysocephala, too few individuals were caught for analysis. Results showed that OSR was more attractive than WFS when coleopteran pests were abundant. In this study, WFS sown for insect conservation may neither favour insect pest conservation at field margin, nor be considered as trap crops. [less ▲]

Detailed reference viewed: 41 (8 ULg)
Full Text
Peer Reviewed
See detailCREATING PERENNIAL FLOWER STRIPS: THINK FUNCTIONAL!
Uyttenbroeck, Roel ULg; Hatt, Séverin ULg; Piqueray, Julien et al

in Scientific Papers. Series A. Agronomy (in press)

In last decades, farmland biodiversity came under large threat. To counteract farmland biodiversity loss and other environmental impacts of intensive agriculture, European farmers can apply Agri ... [more ▼]

In last decades, farmland biodiversity came under large threat. To counteract farmland biodiversity loss and other environmental impacts of intensive agriculture, European farmers can apply Agri-environmental schemes. One of these is the creation of flower strips, a part of the cropping field where flowers are sown or naturally settled. Flower strips are known to increase biodiversity in the agricultural landscape, notably attracting specific insects groups, such as pollinators and natural enemies that can provide valuable pollination and biocontrol services to the crop. However, the plant species composition and management of the strips can have a large influence on the identity and amount of useful insects present in the strips, suggesting the need to develop tailored flower strips to maximize the services delivered. Functional diversity (FD) is sometimes proposed as a promising approach, focusing on plant functional traits rather than plant species itself. Yet, it is not certain that sowing a set of plant species results in the desired vegetation with the desired functional trait composition. Species from soil seed bank or dispersing from neighboring vegetation can settle in the strip, while sown species might not always be equally adapted to local conditions. To test this, we developed seed mixtures with four different levels of FD, based on flower traits, and sew them as flower strips in a conventional arable field. We monitored the vegetation to calculate the FD of the realized vegetation. While the absolute FD values of the realized vegetation were lower than the expected FD values, the realized vegetation showed the same FD gradient as expected from the sown mixtures, indicating that it is possible to manipulate FD in flower strips. [less ▲]

Detailed reference viewed: 29 (5 ULg)
Full Text
Peer Reviewed
See detailAssessing the foraging behavior of Agriotes sordidus wireworms in dual-choice olfactometers
Barsics, Fanny ULg; Fiers, Marie; Fauconnier, Marie-Laure ULg et al

in Communications in Agricultural and Applied Biological Sciences (in press)

The different steps of the foraging process of wireworms (Coleoptera: Elateridae) would be better understood if accurate and holistic information regarding the role of plant-produced chemicals ... [more ▼]

The different steps of the foraging process of wireworms (Coleoptera: Elateridae) would be better understood if accurate and holistic information regarding the role of plant-produced chemicals constituting their environment were available. Volatile organic compounds (VOC) play important roles in the interactions between plants and insects in many ecosystems, whether they take place aboveground or belowground. The roles of VOC are still relatively unknown for wireworms, and deserve attention. Here, we performed three experimentations with barley roots as baits. In the two first, we assessed the effect of chopped roots and fungus infected roots on the orientation of wireworms. In the third experiment, the larvae were confronted to both healthy and fungus infected roots. We discuss the results in terms of suitability of the olfactometers we designed for the investigation of olfaction in wireworms, and we provide suggestions to improve their use. [less ▲]

Detailed reference viewed: 53 (13 ULg)
Full Text
See detailDoes combining a wheat and pea mixture with methyl salicylate reduces aphid populations in both crops?
Chevalier Mendes Lopes, Thomas ULg; Fassotte, Bérénice ULg; Hatt, Séverin ULg et al

Conference (2015, August 25)

Aphids are important pests of wheat and pea. Among the alternative methods to control them with less reliance on insecticides, crop associations already proved to be efficient. However, if increasing the ... [more ▼]

Aphids are important pests of wheat and pea. Among the alternative methods to control them with less reliance on insecticides, crop associations already proved to be efficient. However, if increasing the chemical and structural complexity of vegetation can disrupt their host plants location, the searching efficiency of predators and parasitoids can also be reduced. Therefore, these beneficials may not always be more abundant in such systems. Combining crop associations with attractive semiochemicals for natural enemies can be interesting to solve this problem. In this research, we compared the effect of a wheat and pea pure stand, wheat and pea mixture, and wheat and pea mixture combined with methyl salicylate (MeSA) formulated in alginate gel beads, on the abundance and diversity of aphids and their natural enemies. These were weekly observed on plants during 2013 and 2014 growing seasons. Over these two years, significantly higher numbers of pea aphids (Acyrthosiphon pisum (H.)) were observed in the pure stand of pea compared with both mixtures (with and without MeSA). No significant differences were observed between treatments for wheat aphids (Sitobion avenae (F.), Metopolophium dirhodum (W.) and Rhopalosiphum padi (L.)), which were significantly less abundant than pea aphids. Aphid natural enemies were mainly observed on pea plants. Hoverfly larvae abundance was not significantly different between treatments during both years. The same phenomenon occurred with hoverfly pupae in 2013, while these were significantly more abundant in both mixtures compared with the pure stand in 2014. However, their number did not differ significantly between the mixture with and without MeSA. Few ladybirds and lacewings were observed. No significant differences were observed between treatments for parasitoid mummies in 2013. Their abundance was significantly higher in the pure stand of pea compared with both mixtures in 2014. Results from this study show that mixing wheat and pea is an efficient method to maintain aphid populations at a very low level on pea. The use of MeSA did not show significant effects on natural enemies. However, mixing these crops may be enough to reduce aphid populations under an acceptable threshold. [less ▲]

Detailed reference viewed: 19 (5 ULg)
See detailTuta absoluta (Lepidoptera: Gelechiidae) development on wild and cultivated plant species
Bawin, Thomas ULg; Dujeu, David ULg; Fagan, Maud et al

Conference (2015, August 24)

Introduction: The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important solanaceous crop plants, including tomatoes and potatoes ... [more ▼]

Introduction: The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important solanaceous crop plants, including tomatoes and potatoes. Little is known about the ability of the microlepidoptera to encounter and develop on alternative wild and agricultural plant species. These plants could provide refuges and have to be identified for more efficient integrated management strategies. Objectives: In the present study, we assessed under laboratory conditions the ability of T. absoluta to develop on such plant species referred as potential hosts in the literature, including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae, and Malvaceae. Materials and methods: For each plant species, fitness tests were performed in Petri dishes by isolating single individuals with excised leaf. Two choice behavioral assays were performed in flying tunnels. Volatile organic compounds released by solanaceous plants were trapped using a dynamic collection system, and analyzed by GC-MS. Results: We found that Solanum species allowed higher larval survivability and shorter development time (from egg to adult emergency) compared to the other plants. Non-solanaceous plants were not able to sustain T. absoluta larvae. Two choice behavioral assays revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to other tested solanaceous plants. The hypothesis that female host plant choice is influenced by plant volatile organic compounds was tested. Solanum volatile profiles showed similarities, and were presenting quantitative and qualitative differences with the other tested solanaceous plants, providing some explanations in the observed behavioral discrimination. Further electrophysiological and behavioral assays are required to confirm the effect of specific chemicals on the choice of the oviposition site in T. absoluta. Conclusion: It can be concluded that Solanum species are the more suitable hosts for T. absoluta development. Other solanaceous plant species could be opportunistically colonized with little incidence but care should be taken in these results as genetic variability in insects and plants, as well as plant physiological state, might have an impact on the pest survivability. [less ▲]

Detailed reference viewed: 9 (2 ULg)
Full Text
Peer Reviewed
See detailLa lutte contre les moustiques (Diptera: Culicidae): diversité des approches et application du contrôle biologique
Bawin, Thomas ULg; Seye, Fawrou; Boukraa, Slimane ULg et al

in Canadian Entomologist (2015), 147(4), 476-500

Many mosquito (Diptera: Culicidae) species are zoonotic vectors responsible for numerous infectious diseases of medical and veterinary importance. Currently, changes in the vectors’ geographical ... [more ▼]

Many mosquito (Diptera: Culicidae) species are zoonotic vectors responsible for numerous infectious diseases of medical and veterinary importance. Currently, changes in the vectors’ geographical distribution induced chiefly by anthropogenic factors are accompanied by emerging and reemerging infectious diseases in Europe and North America. Since the advent of synthetic insecticides during the Second World War, mosquitoes are the object of considerably expanded and deepened research. In an integrated pest management context, means of control are now mainly classified as: (1) environmental management and physical control, (2) chemical control, (3) genetic control, and (4) biological control by means of entomophagous predators and entomopathogenic microorganisms. In this context, these last have significant potential because of their ability to infect and kill their host with more or less targeted selectivity. This article proposes to emphasize biological control among other techniques in mosquito control, and to assess the potential and the opportunities offered by entomopathogenic bacteria, viruses and fungi. Finally, their use as biopesticides is discussed. [less ▲]

Detailed reference viewed: 99 (28 ULg)
Full Text
See detailMeeting farmers who sowed wildflower strips - The survey methodology
Méhu, Marie; Hatt, Séverin ULg; Brédart, David ULg et al

Scientific conference (2015, July 31)

Detailed reference viewed: 19 (2 ULg)
Full Text
Peer Reviewed
See detailCould alternative solanaceous hosts act as refuges for the tomato leafminer, Tuta absoluta?
Bawin, Thomas ULg; Dujeu, David ULg; De Backer, Lara ULg et al

in Arthropod-Plant Interactions (2015), 9(4), 425-435

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous plants. The characterization of its effective ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous plants. The characterization of its effective host range could help to understand and prevent the dispersion behavior of the insect in the environment. In this study, the ability of T. absoluta to locate and develop on wild (Solanum nigrum, Atropa belladonna, Datura stramonium) and cultivated (Solanum tuberosum) solanaceous plant species under laboratory conditions was assessed. Dual-choice behavioral assays performed in flying tunnels (S. tuberosum versus another plant) revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to the other tested plants. The volatile molecules released by each tested plant species provide some explanations in the observed behavioral discrimination: S. nigrum and S. tuberosum volatile profiles were similar, and were presenting quantitative and qualitative differences with the other tested Solanaceous plants. To determine whether the host plant choice was adaptive or not, we have finally conducted fitness assays, by rearing T. absoluta larvae on each plant species and have shown that Solanum species allowed higher larval survivability and lower development time (from egg to adult emergency) compared to the other plants. We conclude that Solanum species are suitable host plants for T. absoluta, but other Solanaceous plant species could be opportunistically colonized with fewer incidences. [less ▲]

Detailed reference viewed: 57 (10 ULg)
Full Text
Peer Reviewed
See detailDes bandes fleuries pour la lutte biologique : état des lieux, limites et perspectives en Wallonie – Une synthèse bibliographique.
Hatt, Séverin ULg; Uyttenbroeck, Roel ULg; Bodson, Bernard ULg et al

in Entomologie Faunistique = Faunistic Entomology (2015), 68

Managing field margins takes part of the Agri-Environmental Measures supported by the European Union in Wallonia. Among possible infrastructures, wildflower strips are known to conserve a wide diversity ... [more ▼]

Managing field margins takes part of the Agri-Environmental Measures supported by the European Union in Wallonia. Among possible infrastructures, wildflower strips are known to conserve a wide diversity of insects, including natural enemies that can be mobilized to biologically control pests. However, the efficiency of pest control is not guaranteed. It depends mainly on the ability of flowers to attract natural enemies at the right time and to keep them in this environment while favoring their migration into adjacent crops. A reflection on the composition of the floral mixtures may optimize their capacity in biological control. In this context, this review paper put forward the interest of considering functional traits of flowers and presents the concept of functional diversity. Furthermore, the sown perennial wildflower strips should be maintained by regular mowing. However, mowing affects both insect and plant populations due to momentary destruction of the habitat. An appropriate management of field margins is therefore needed to optimize the pest control service provided. [less ▲]

Detailed reference viewed: 26 (4 ULg)
Full Text
Peer Reviewed
See detailMultiple analyses of microbial communities applied to the gut of the wood-feeding termite Reticulitermes flavipes fed on artificial diets
Tarayre, Cédric ULg; Bauwens, Julien ULg; Mattéotti, Christel et al

in Symbiosis (2015)

The purpose of this work was the observation of the differences between the microbial communities living in the gut of the termite Reticulitermes flavipes fed on different diets. The termites were fed on ... [more ▼]

The purpose of this work was the observation of the differences between the microbial communities living in the gut of the termite Reticulitermes flavipes fed on different diets. The termites were fed on poplar wood (original diet) and artificial diets consisting of crystalline cellulose (with and without lignin), α-cellulose (with and without lignin) and xylan. The termites were then dissected and the protist communities were analyzed through microscopy, leading to the conclusion that protist species are strongly influenced by diets. BIOLOG ECO Microplates® were used to assess the metabolic properties of the different types of consortia, highlighting strong differences on the basis of principal component analysis and calculation of similarity rates. The microorganisms were cultivated in liquid media corresponding to the artificial diets before being characterized through a metagenetic analysis of gut microbiota (16S ribosomal DNA). This analysis identified several phyla: Acidobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Fibrobacteres, Firmicutes, Nitrospirae, OP9, Planctomycetes, Proteobacteria, Spirochaetes, TM6, Tenericutes, Verrucomicrobia and WS3. The OTUs were also determined and confirmed the abundance of Proteobacteria, Bacteroidetes, Firmicutes and Verrucomicrobia. It was possible to isolate several strains from the liquid media, and one bacterium and several fungi were found to produce interesting enzymatic activities. The bacterium Chryseobacterium sp. XAvLW produced α-amylase, β-glucosidase, endo-1,4-β-D-glucanase, endo-1,4-β-D-xylanase and filter paper-cellulase, while the fungi Sarocladium kiliense CTGxxyl and Trichoderma virens CTGxAviL generated the same activities added with endo-1,3-β-D-glucanase. [less ▲]

Detailed reference viewed: 30 (10 ULg)
Full Text
Peer Reviewed
See detailOrco mediates olfactory behaviors and winged morph differentiation induced by alarm pheromone in the grain aphid, Sitobion avenae
Fan, Jia; Zhang, Yong; Francis, Frédéric ULg et al

in Insect Biochemistry and Molecular Biology (2015), 64

Olfaction is crucial for short distance host location and pheromone detection by insects. Complexes of olfactory receptors (ORs) are composed of odor-specific ORs and OR co-receptors (Orco). Orcos are ... [more ▼]

Olfaction is crucial for short distance host location and pheromone detection by insects. Complexes of olfactory receptors (ORs) are composed of odor-specific ORs and OR co-receptors (Orco). Orcos are widely co-expressed with odor-specific ORs and are conserved across insect taxa. A number of Orco orthologs have been studied to date, although none has been identified in cereal aphids. In this study, an Orco gene ortholog was cloned from the grain aphid, Sitobion avenae, and named “SaveOrco”; RNA interference (RNAi) reduced the expression of SaveOrco to 34.11% in aphids, resulting in weaker EAG (electroantennogram) responses to plant volatiles (Z-3-hexene-1-ol; methyl salicylate, MeSA) and aphid alarm pheromone (E-b-farnesene, EBF). Aphid wing differentiation induced by EBF was investigated in both RNAi treated and untreated aphids. EBF induced production of winged aphids in both pre-natal and postnatal periods in untreated aphids, but no such induction was observed in the RNAi-treated aphids. We conclude that SaveOrco is crucial for the aphid's response to pheromones and other volatiles, and is involved in wing differentiation triggered by EBF [less ▲]

Detailed reference viewed: 45 (0 ULg)
Full Text
See detailAgroecology: Unity into diversity
Hatt, Séverin ULg; Artru, Sidonie ULg; Boeraeve, Fanny ULg et al

Poster (2015, May 21)

What does agroecology suggest ? Next to the theoretical agroecological principles, we present illustrative examples from farming practices, through the food system, up to the way of carrying agricultural ... [more ▼]

What does agroecology suggest ? Next to the theoretical agroecological principles, we present illustrative examples from farming practices, through the food system, up to the way of carrying agricultural research and education. [less ▲]

Detailed reference viewed: 25 (2 ULg)
See detailTuta absoluta (Lepidoptera: Gelechiidae) development on wild and cultivated plant species
Bawin, Thomas ULg; Dujeu, David ULg; Fagan, Maud ULg et al

Conference (2015, May 19)

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little is known about the ability of this microlepidoptera to encounter and develop on alternative wild and agricultural plant species. These plants could provide refuges and have to be identified for more efficient integrated management strategies. In the present study, we assessed under laboratory conditions the ability of T. absoluta to develop on such plant species referred as potential hosts in the literature, including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae, and Malvaceae. For each plant species, fitness tests were performed in Petri dishes by isolating single individuals with excised leaf. We found that Solanum species allowed higher larval survivability and shorter development time (from egg to adult emergency) compared to the other plants. Non-solanaceous plants were not able to sustain T. absoluta larvae. Two choice behavioral assays performed in flying tunnels revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to other tested solanaceous plants. These results appeared to be consistent with survival rates and development times. Because larval survivability depends on the female’s oviposition choice, the hypothesis that host plant choice is influenced by plant volatile organic compounds has to be tested. Volatile organic compounds released by solanaceous plants were trapped using a dynamic collection system, and analyzed by GC-MS. Solanum volatile profiles showed similarities, and were presenting quantitative and qualitative differences with the other tested solanaceous plants, providing some explanations in the observed behavioral discrimination. Further electrophysiological and behavioral assays are required to confirm the effect of specific chemicals on the choice of the oviposition site in T. absoluta. It can be concluded that Solanum species are the more suitable hosts for T. absoluta development. Other solanaceous plant species could be opportunistically colonized with little incidence but care should be taken in these results as genetic variability in insects and plants, as well as plant physiological state, might have an impact on the pest survivability. [less ▲]

Detailed reference viewed: 39 (5 ULg)
Peer Reviewed
See detailEfficiency of pheromone-based formulations against phytophagous pests
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Chevalier Mendes Lopes, Thomas ULg et al

Conference (2015, May 19)

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or ... [more ▼]

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or indirect biocide activity is one promising alternative option. Our researches focus on the identification of appropriate formulations releasing volatile organic compounds that are attractant for natural enemies of insect pests. However, the elaboration of slow-release devices that ensure stable and controlled release of active volatile compounds is quite challenging. Here, we developed a formulation based on E-β-farnesene and (-)-β-caryophyllene, these two semiochemicals having strong attractive potential on aphid natural enemies including lady beetles and hoverflies. Both compounds were encapsulated together in alginate gel beads. The blend efficiency was first evaluated through laboratory assays, and then in wheat and broad bean fields, by considering the abundance and diversity of aphids and their natural enemies. [less ▲]

Detailed reference viewed: 38 (6 ULg)
Full Text
See detailAssessment of the species richness of highly eusocial bees according with habitat in Gabon
Fabre Anguilet, Edgard ULg; Bengone Ndong, Toussaint; Nguyen, Bach Kim ULg et al

Poster (2015, May 18)

Bees are among the most e ective pollinators. These insects include honeybee and stin- gless bee. In Africa, habitat loss is the main threat to these insects. This loss of habitat is largely due to ... [more ▼]

Bees are among the most e ective pollinators. These insects include honeybee and stin- gless bee. In Africa, habitat loss is the main threat to these insects. This loss of habitat is largely due to various human activities. An evaluation of the richness of social bees in three locaties in Gabon (Central Africa) was conducted from October 2013 to March 2014: Kougouleu who underwent deforestation and implantation of food crops, forest area Mas- sengalini in bu er zone of protected area of Lope and Lekokodiba in logging concession of Preccious Woods Gabon. For this, a collection was conducted using yellow traps lled with a mixture of water and honey and using a hand vacuum in 20 sites in each area. The number of species was compared to that estimated there are about thirty years. Eleven species of social bees (Apis mellifera adansonii and ten stingless bee species) were collected, of which 5 to Kougouleu, 8 to Massengalini and 11 to L ekokodiba. Honeybee has been collected in all localities. Forest localities are distinguished from Kougouleu by higher species diversity. This di erence is highly signi cant (Kruskal-Wallis 2 = 45.362, df = 2 and p-value<0.001). A decrease of approximately 50% of the number of stingless bee species in 30 years was found to Kougouleu, while the number of social bee species varies little in forest localities. Our study shows that the loss of forest habitat causes a decline in the species richness of social bees and stingless bees are more sensitive to this loss as the honeybee. [less ▲]

Detailed reference viewed: 22 (1 ULg)