References of "Bawin, Thomas"
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See detailPhylogenetic study of Aedes albopictus and Aedes koreicus (Diptera, Culicidae) origin, two invasive mosquito species in Belgium
Raharimalala, Fara Nantenaina ULg; Boukraa, Slimane ULg; Bawin, Thomas ULg et al

Poster (2014, April 10)

The main ways of the introduction of invasive mosquito species in Europe were greatly facilitated by the importation of used tires and plants from the South of China (Dracaena sanderiana, called "Lucky ... [more ▼]

The main ways of the introduction of invasive mosquito species in Europe were greatly facilitated by the importation of used tires and plants from the South of China (Dracaena sanderiana, called "Lucky bamboo"), which are a very good breeding sites of these mosquitoes (www.eidatlantique.eu). For Belgium, several species of exotic mosquitoes have already been listed such as Ochlerotatus japonicus japonicus, Aedes albopictus and A. koreicus. We have captured one male of A. albopictus in Belgium in July 2013 (Boukraa et al, 2013), and teams from other entomologist have been able to find several individuals in the months that have followed our discovery (personal communication). However, his presence was reported first in 2000 (Schaffner et al. 2004) but until 2012, no individuals have been found (Versteirt et al., 2013). We also could find larvae of A. koreicus in abundance. These discovery suggest that these two invasive species are being established in Belgium. Methods: Adult mosquitoes were collected by CO2-baited traps Mosquito Magnet Liberty Plus (MMLP) and immature stages by the dipping method from 8 sites of Belgium. Each individual was then determined morphologically. For A. albopictus and A. koreicus, reconfirmation by molecular method was performed with COI and ND5 mitochondrial primers and sequences were then aligned with those of mosquitoes available in databases by using BioEdit and Multialn softwares. The two gene sequences were concatenated to improve the reliability of the phylogenetic analysis and were carried out by using the Seaview software based on maximum likelihood (ML) methods. Trees were then constructed with the general time reversible (GTR) model, and branch supports were estimated by bootstrapping with 1000 replicates. Result: The aim of this work will focus on the study of the probable origin of these two species of Aedes, which are for the moment safe yet, but that might become dangerous in the event of massive outbreak. The knowledge of the probably origin of the two invasive mosquitoes allow take more protection against their way to enter in the country. [less ▲]

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See detailBiofilms from entomopathogenic fungi in mosquito control
Bawin, Thomas ULg; Boukraa, Slimane; Seye, Fawrou et al

Poster (2014, February 07)

Mosquitoes (Diptera: Culicidae) are zoonotic vectors of medical and veterinary importance. As part of an integrated vector control, metabolites secreted by entomopathogenic fungi could be developed as ... [more ▼]

Mosquitoes (Diptera: Culicidae) are zoonotic vectors of medical and veterinary importance. As part of an integrated vector control, metabolites secreted by entomopathogenic fungi could be developed as biopesticides. In this context, filamentous microorganisms growing on a support as biofilm in a liquid medium would offer several advantages in bioreactor regarding performances and metabolites recovery. The production of toxic metabolites by an entomopathogenic fungus Aspergillus flavus in such conditions was assessed. Three initial inoculum levels, i.e. 10^1, 10^3 and 10^6 spores/ml of PYG medium, have been tested in shake flask with or without support. Toxicity tests were performed on Culex quinquefasciatus larvae using dilutions of 1, 2, 4, 6, 8 and 10% of liquid cultures. The results indicated that A. flavus tends to form pellets in submerged culture; the size and the amount of pellets was affected by the initial inoculum level of spores. Under similar conditions, the filaments fixed on a support and didn’t appear in free form in the liquid. Toxicity tests revealed differences between both free and fixed forms. All combined conditions, LC50s ranging up to dilutions of 2.2 and 4.8% were observed within 48 hours. Secretomes could be compared between these culture conditions by proteomic and metabolomic approaches. [less ▲]

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See detailUsing micro-injection technique to assess fungal toxicity in mosquito control
Bawin, Thomas ULg; Boukraa, Slimane; Seye, Fawrou et al

in Communications in Agricultural and Applied Biological Sciences (2014, February 07), 79(1), 181-185

Topical application of insecticidal compounds allows directly exposing these substances on insect tissues and measuring their toxicity while ignoring many factors. However, this technique remains ... [more ▼]

Topical application of insecticidal compounds allows directly exposing these substances on insect tissues and measuring their toxicity while ignoring many factors. However, this technique remains difficult to apply on mosquito larvae considering their aquatic lifestyle. Micro-injection could be used for the direct deposition of toxic compounds in the larvae. Capillaries exhibiting an injection tip with an external diameter of 0.5 mm have been designed from silica tubes. For each treatment, a capillary is mounted on a pump connected to a flow rate regulator. Culex quinquefasciatus larvae were injected with 10^7 spores/ml of entomopathogenic fungi (Aspergillus clavatus, Metarhizium anisopliae, Metarhizium sp.). Mortalities were recorded daily during 72h. The distribution of spores stained with methylene blue and injected into the body of larvae was also observed according to the system described. Results showed that spores were distributed over the whole body. The injection of Aspergillus clavatus, Metarhizium anisopliae and Metarhizium sp spores induced corrected mortalities of 62%, 53% and 57% after 72h, and differed statistically from control groups. Finally, post-mortem emergences of filaments from dead larvae were observed in the case of the three fungal strains confirming spore viability. Injection of inactivated spores (or inert bodies of similar size) could help to reject the hypothesis of a response due to the presence of foreign bodies. [less ▲]

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See detailReintroduction of the invasive mosquito species Aedes albopictus in Belgium in July 2013
Boukraa, Slimane ULg; Raharimalala, Fara Nantenaina ULg; Zimmer, Jean-Yves ULg et al

in Parasite (Paris, France) (2013), 20(54),

Since its first report in 2000, the invasive mosquito Aedes albopictus was not found any more during the different entomological inspections performed at its place of introduction in Belgium between 2001 ... [more ▼]

Since its first report in 2000, the invasive mosquito Aedes albopictus was not found any more during the different entomological inspections performed at its place of introduction in Belgium between 2001 and 2012. In July 2013, one adult male was captured at the same site (a platform of imported used tires located in Vrasene, Oost-Vlaanderen Province), during a monitoring using CO2-baited trap. This finding suggests the reintroduction of the species in Belgium via the used tire trade. [less ▲]

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See detailRéintroduction d'Aedes albopictus, une menace pour la Belgique? (Diptera: Culicidae)
Boukraa, Slimane ULg; Raharimalala, Fara Nantenaina ULg; Zimmer, Jean-Yves ULg et al

Conference (2013, November 23)

Actuellement, l’espèce Aedes albopictus Skuse est considérée comme le moustique le plus invasif dans le monde entier et l’un des plus importants vecteurs d’arbovirus (notamment chikungunya et dengue). En ... [more ▼]

Actuellement, l’espèce Aedes albopictus Skuse est considérée comme le moustique le plus invasif dans le monde entier et l’un des plus importants vecteurs d’arbovirus (notamment chikungunya et dengue). En Belgique, Ae. albopictus a été introduit pour la première fois en 2000 à Vrasene (Province de Flandre-Orientale), dans une entreprise de recyclage des pneus usagés en provenance des États-Unis et du Japon. Plusieurs autres inspections ont été effectuées (2001-2012) après ce premier rapport, mais aucun autre spécimen n’a été trouvé. L’espèce était considérée comme éliminée naturellement et aucune nouvelle introduction n’avait été signalée. Dans le cadre d'une étude de surveillance de moustiques réalisée dans plusieurs endroits à travers la Belgique en 2013, un adulte mâle d’Ae. albopictus a été capturé à l'aide d’un piège à CO2 à Vrasene dans la même entreprise de recyclage de pneus (51 ° 12'49 "N, 4 ° 11'37" E; juillet 2013). L’espèce a été confirmée par identification morphologique et moléculaire. Cette redécouverte d’Ae. albopictus ainsi que son absence durant les treize dernières années, démontrent sa réintroduction en Belgique via le commerce de pneus usagés. Une étude sur la survie et la dispersion de ce moustique en Belgique, ainsi que de son écologie dans les pays voisins pourrait fournir des indications importantes pour élucider davantage son caractère invasif et identifier les zones à haut risque. [less ▲]

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See detailEcology of mosquitoes (Diptera, Culicidae) potentially vectors of arboviruses according to the kinds of animal husbandry in Belgium
Boukraa, Slimane ULg; De la Grandière de Noronha Cotta, Maria Ana ULg; Bawin, Thomas ULg et al

Poster (2013, November 12)

Human activity, commercial exchanges and climate changes current and future, could favor the (re)-emergence of vector-borne diseases, by inducing changes on Culicidae populations. This study aims to ... [more ▼]

Human activity, commercial exchanges and climate changes current and future, could favor the (re)-emergence of vector-borne diseases, by inducing changes on Culicidae populations. This study aims to determine the potential importance of agricultural environments, especially cattle farms and equestrian, to welcome and favor the proliferation of some species of mosquito responsible for transmission of arboviruses. To better understand the structure of the Culicidae population and identify habitats favorable to the development of each species, a taxonomic inventory was conducted in 2008 (III, VI and X) and 2009 (V and IX) in ten cattle farms, and in 2011 (VI-X) and 2012 (VI-IX) in six equestrian farms located in Belgium. The harvest of mosquitoes is based on adult trapping by CO2-traps (Mosquito magnet) and on larval sampling at the level of 64 biotopes such as water troughs, used tires, abandoned utensils and temporary puddles or not. The morphotaxonomic of larvae and genitalia, and molecular study showed the presence of 15 species: Culiseta annulata Schrank, 1776; Cs. morsitans Theobald, 1901 Anopheles claviger s.s. Meigen, 1804; An. maculipennis s.s. Meigen, 1818; An. messeae Falleroni, 1926; An. plumbeus Stephens, 1828; Culex pipiens molestus Forskal, 1775; Cx. pipiens pipiens L., 1758; Cx. torrentium Martini, 1925; Cx. hortensis hortensis Ficalbi, 1889; Cx. territans Walker, 1856; Coquillettidia richiardii Ficalbi, 1889; Ochlerotatus geniculatus Olivier, 1791; Oc. cantans Meigen, 1818 and Aedes cinereus Meigen, 1818. Among the 57,680 individuals examined, Cx. pipiens s.l., Cx. torrentium and Cs. annulata are the dominants species and ubiquitous in all farms visited. The species of the genus Anopheles have strong ecological requirements and are therefore associated with some special habitats; other species however have a strong ability to adapt and therefore attend a wide variety of biotopes (Cx. pipiens s.l., Cx. torrentium and Cs. annulata). Water troughs, used tires and ponds are the most favorable habitats for larval development of Culicidae. The species potentially vectors of arboviruses that can cause problems in epidemiological farms are Cx. pipiens s.l., Cx. torrentium and Cq. richiardii. Therefore, despite the low diversity of mosquito observed within the livestock environments, they represent a significant risk for the reproduction of some potential vectors of arboviruses. In addition, some larval habitats constitute very favorable sites for proliferation of mosquito, causing a real problem of nuisance for animals of farms. [less ▲]

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See detailImportation récente d’Aedes albopictus en Belgique : modes d’introduction, risques et gestion des risques
Boukraa, Slimane ULg; Raharimalala, Fara Nantenaina ULg; Zimmer, Jean-Yves ULg et al

Conference (2013, October 25)

L'environnement et les changements climatiques, ainsi que la mondialisation des échanges commerciaux internationaux peuvent affecter la distribution des pathogènes et/ou des arthropodes vecteurs ... [more ▼]

L'environnement et les changements climatiques, ainsi que la mondialisation des échanges commerciaux internationaux peuvent affecter la distribution des pathogènes et/ou des arthropodes vecteurs. Actuellement, l’espèce Aedes albopictus Skuse est considérée comme le moustique le plus invasif dans le monde entier et l’un des plus importants vecteurs d’arbovirus (notamment chikungunya et dengue). En Belgique, Ae. albopictus a été introduit pour la première fois en 2000 à Vrasene (Province de Flandre-Orientale), dans une entreprise de recyclage des pneus usagés en provenance des États-Unis et du Japon. Plusieurs autres inspections ont été effectuées (2001-2012) après ce premier rapport, mais aucun autre spécimen n’a été trouvé. L’espèce était considérée comme éliminée naturellement et aucune nouvelle introduction n’avait été signalée. Dans le cadre d'une étude de surveillance de moustiques réalisée dans plusieurs endroits à travers la Belgique en 2013, un adulte mâle d’Ae. albopictus a été capturé à l'aide d’un piège à CO2 à Vrasene dans la même entreprise de recyclage de pneus (51°12'49" N, 4°11'37" E; juillet 2013). L’espèce a été confirmée par identification morphologique et moléculaire. Cette redécouverte d’Ae. albopictus ainsi que son absence durant les treize dernières années, démontrent sa réintroduction en Belgique via le commerce de pneus usagés. Une étude sur la survie et la dispersion de ce moustique en Belgique, ainsi que de son écologie dans les pays voisins pourrait fournir des indications importantes pour élucider davantage son caractère invasif et identifier les zones à haut risque. Contexte Aedes albopictus (Skuse, 1894) (Diptera: Culicidae), communément appelé « le moustique tigre », est une espèce invasive originaire d’Asie du Sud-Est. Une nouvelle réintroduction de ce vecteur d’arbovirus a été enregistré en été 2013 en Belgique. Cette présentation abordera successivement : (a) L’invasion d’Ae. albopictus et importance médicale, (b) (Ré)-Introduction d’Ae. albopictus en Belgique, (c) Risque lié à l’introduction et à l’adaptation d’Ae. albopictus en Belgique, (d) Gestion de risque et contrôle. a. Invasion d’Ae. albopictus et importance médicale Depuis la fin des années 70s, Ae. albopictus connait une propagation explosive dans le monde entier où il est considéré actuellement comme le moustique le plus invasif dans le monde (1). La mondialisation des échanges commerciaux, notamment les pneus usagés (2) et le Lucky Bambou (3), est un facteur clé de cette invasion. En Europe, il a été signalé dans 20 pays et est aujourd'hui bien installé dans la région méditerranéenne (1). Ae. albopictus fait partie des plus importants vecteurs d’arbovirus, en particulier pour les virus de la dengue et du chikungunya (1), et des filarioses animales notamment Dirofilaria spp. (4). Le risque d'apparition et la propagation de ces arbovirus aux régions non épidémiques ont surtout augmenté dans les régions où Ae. albopictus est établi. Cette hypothèse est démontrée à plusieurs reprises, notamment les récentes transmissions autochtones du chikungunya et de la dengue en Italie, en Croatie et en France (1). b. (Ré)-Introduction d’Ae. albopictus en Belgique En Belgique, Ae. albopictus a été introduit pour la première fois en 2000 à Vrasene (Province de Flandre-Orientale), dans une entreprise de recyclage des pneus usagés en provenance des États-Unis et du Japon (5). Plusieurs autres inspections ont été effectuées (2001-2012) après ce premier rapport, mais aucun autre spécimen n’a été trouvé (6, Schaffner données non publiées). L’espèce était considérée comme éliminée naturellement et aucune nouvelle introduction n’avait été signalée (6). Cependant, une étude sur la surveillance de moustiques réalisée dans plusieurs endroits à travers la Belgique en 2013 a de nouveau signalé la capture d’Ae. albopictus à Vrasene, dans la même entreprise de recyclage de pneus. Cette redécouverte d’Ae. albopictus, ainsi que l'absence de toute constatation au cours des années précédentes (2001-2012), démontre sa réintroduction en Belgique via le commerce des pneus usagés (7). c. Risque lié à l’introduction et à l’adaptation d’Ae. albopictus en Belgique Aedes albopictus est un vecteur efficace confirmé des virus de la dengue et du chikungunya (1), ainsi que des filarioses animales notamment Dirofilaria spp. (4) ; la Belgique enregistre de plus régulièrement des cas de chikungunya importés (8). Ainsi, s'il s'établit dans le pays, Ae. albopictus peut devenir une menace importante et réelle pour la santé humaine et animale tant par son rôle de vecteur d'agents pathogènes que par sa nuisance. d. Gestion de risque et contrôle Une étude sur la survie et la dispersion d’Ae. albopictus en Belgique, ainsi que sur sa bio-écologie dans les pays voisins pourrait fournir des indications importantes pour élucider davantage son caractère invasif, et identifier les zones à haut risque. Une réponse proactive rapide est essentielle pour la lutte anti-vectorielle afin d’éviter son installation en Belgique. Cela inclut la mise en œuvre rapide de mesures de contrôle, avant que l’élimination ne devienne impossible (9). Les programmes de surveillance et de contrôle doivent cibler davantage toutes les zones possibles d’introduction de ce vecteur, en particulier les entreprises du commerce international des pneumatiques et des plantes ornementales telle que le Lucky Bambou. Ces programmes doivent également être appliqués durant toute la saison d’activité d’Ae. albopictus, sous une logique de lutte anti-vectorielle intégrée (10). A cet effet, l’appel aux moyens de lutte mécanique et les traitements larvicides sont fortement recommandés. Le recours aux traitements adulticides cependant, sera justifié uniquement en cas d’abondance de l’espèce due à de nouvelles réintroductions. Conclusion Les réintroductions d’Ae. albopictus en Belgique via l’importation de pneus usagés, l’environnement favorable à son installation et la confirmation régulière de cas importés du chikungunyia rendent la Belgique vulnérable aux risques d’une transmission autochtone de cette maladie infectieuse. Vu que plusieurs pays d'Europe de l'Ouest connaissent actuellement des introductions répétées d'Ae. albopictus sur leurs territoires, la mobilisation et la coordination des surveillances entomologiques entre ces pays - y compris la Belgique - sont devenues plus que nécessaires afin de traquer toutes les voies potentielles de réintroductions. Compte tenu du grand pouvoir adaptatif et invasif d'Ae. albopictus, il est recommandé d’agir rapidement et efficacement pour éliminer cette espèce avant son installation et sa dissémination ; ces mesures permettraient ainsi de réduire le risque de transmission des arboviroses en Belgique. Référence 1. J. M. Medlock, K. M. Hansford, F. Schaffner, V. Versteirt, G. Hendrickx, H. Zeller, et al. A Review of the Invasive Mosquitoes in Europe: Ecology, Public Health Risks, and Control Options. Vect born Zoo Dis, 12, 435-447 (2012). 2. E. A. Gould, S. Higgs. Impact of climate change and other factors on emerging arbovirus diseases. Trans R Soc Trop Med Hyg, 103(2), 109–121 (2009). 3. E. J. Scholte, E. Dijkstra, H. Blok, A. De Vries, W. Takken, A. Hofhuis et al. Accidental importation of the mosquito Aedes albopictus into the Netherlands: a survey of mosquito distribution and the presence of dengue virus. Med Vet Entomol, 22, 352-358 (2008). 4. G. Cancrini, P. Scaramozzino, S. Gabriella, M. Di Paolo, L. Toma, R. Romi. Aedes albopictus and Culex pipiens implicated as natural vectors of Dirofilaria repens in central Italy. J Med Entomol, 44, 1064–1066 (2007). 5. F. Schaffner, W. Van Bortel, M. Coosemans. First record of Aedes (Stegomya) albopictus in Belgium. J Am Mosq Cont Assoc 20, 201-203 (2004). 6. V. Versteirt, S. Boyer, D. Damiens, E. M. De Clercq, W. Dekoninck, E. Ducheyne et al. Nationwide inventory of mosquito biodiversity (Diptera: Culicidae) in Belgium. Europe Bull Entomol Res 103, 193-203 (2013). 7. S. Boukraa, F. N. Raharimalala, J.-Y. Zimmer, F. Schaffner, T. Bawin, E. Haubruge, et al. Rediscovery of Aedes albopictus in Belgium: introduction or establishment ? Emerg Infect Dis, (Article soumis) (Septembre, 2013) 8. E. Bottieau, M. Van Esbroeck, L. Cnops, J. Clerinx, A. Van Gompel. Chikungunya infection confirmed in a Belgian traveller returning from Phuket (Thailand). Euro Surveill, 14, 1-2 (2009). 9. F. Schaffner, R. Bellini, D. Petrić, E.-J. Scholte, H. Zeller, L. Marrama Rakotoarivony. Development of guidelines for the surveillance of invasive mosquitoes in Europe. Parasit Vectors, 6, 209 (2013). 10. Centre national d’Expertise sur les Vecteurs. Introduction d’arthropodes vecteurs au niveau des plateformes portuaires et aéroportuaires. Identification des principaux risques (2012). [less ▲]

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See detailBacterial diversity of field-caught mosquitoes from different regions of Belgium and potential impact on virus transmission
Raharimalala, Fara Nantenaina ULg; Boukraa, Slimane ULg; Bawin, Thomas ULg et al

Poster (2013, October 02)

Several vectors disease presented a resistance to various pesticides currently used. Endosymbiotic bacteria was an alternative solution found because of their probably interactive effects with their host ... [more ▼]

Several vectors disease presented a resistance to various pesticides currently used. Endosymbiotic bacteria was an alternative solution found because of their probably interactive effects with their host. According to the introduction risks of these virus and disease dispersion, we propose to investigate the bacterial endosymbiont role in Culicidae in Belgium. Among the 30 species of mosquitoes identified in this country, about ten are considered as potential vectors of arboviruses. In this study, eleven species of Culicidae belonging to five genera (Culex pipiens s.l., Cx. torrentium, Cx. hortensis, Anopheles claviger, An. maculipennis s.l., An. plumbeus, Culiseta annulata, Ochlerotatus geniculatus, Oc. dorsalis, Aedes albopictus and Coquillettidia richiardii) mosquitoes fields from eight sites of Belgium were used for the screening of the presence of six genera endosymbiotic bacteria (Wolbachia sp, Commamonas sp, Delftia sp, Pseudomonas sp, Acinetobacter sp and Asaia sp) according their possible impact in mosquito biology. PCR was done for the screening of endosymbiotic bacteria mosquitoes studied. A total of 176 individuals (144 larvae and 32 adults) were used. Our results allowed us to confirm the absence of Wolbachia in An. clavigere, An. maculipennis s.l and Cx. torentium. Acinetobacter was found in every species. Current advances in understanding the mosquito–microbiota relationships may have a great impact in a better understanding of some traits of mosquito biology and in the development of innovative mosquito-borne disease-control strategies aimed to reduce mosquito vectorial capacity and/or inhibiting pathogen transmission. [less ▲]

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See detailAssessment of bacterial persistence in mosquitoes according to microinjection assays in Belgium
Raharimalala, Fara Nantenaina ULg; Bawin, Thomas ULg; Boukraa, Slimane ULg et al

Poster (2013, October 02)

The problems caused by the massive used of pesticides have resulted in the establishment of resistant vectors besides the destruction of the environment. Furthermore, climate change has consequently ... [more ▼]

The problems caused by the massive used of pesticides have resulted in the establishment of resistant vectors besides the destruction of the environment. Furthermore, climate change has consequently modified the comportment of disease vectors. Current research tends to look for alternative means to overcome the problem. The goal of that study was to undertaken the way there this objective. By their presence or absence, endosymbiotic microorganisms can influence vector competence and vectorial capacity. Our research aims to study the effect of the introduction of endosymbiotic bacteria in the mosquito species that could be potential vectors of disease in Belgium. Method used was the microinjection of endosymbiotic bacteria within the detected exempt mosquito species. Three genus of suspected vectors belonging to Aedes, Anopheles and Culex were microinjected at different stages of their life cycle (eggs, larvae, pupae, and adults), and survivability of mosquitoes and persistence of microorganism were determined. Results show that survival in the different stages was variable. Furthermore, persistence of endobacteria was different depending genus and stages studied [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 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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See detailDiversity and breeding sites of mosquitoes (Diptera, Culicidae) potentially vectors of arboviruses in Belgian equestrian farms
Boukraa, Slimane ULg; De la Grandière de Noronha Cotta, Maria Ana ULg; Bawin, Thomas ULg et al

Poster (2012, October 08)

This study aims to determine the potential importance of the livestock farms, especially equestrian, to welcome and favor the proliferation of certain species of mosquito responsible for transmission of ... [more ▼]

This study aims to determine the potential importance of the livestock farms, especially equestrian, to welcome and favor the proliferation of certain species of mosquito responsible for transmission of arboviruses. The study of biodiversity of Culicidae in the horse farms in Belgium is carried out on species sampled at 64 biotopes in six stations study. Five surveys were realized during 2011 (June, July, August and October) and one in 2012 (June). The morphotaxonomic and molecular study of mosquitoes collected showed the presence of ten species: Culisata annulata Schrank, 1776; Anopheles claviger s.s. Meigen, 1804; An. maculipennis s.s. Meigen, 1818; An. messae Falleroni, 1926; Culex pipiens molestus Forskal, 1775; Cx. pipiens pipiens Linné, 1758; Cx. torrentium Martini, 1925; Cx. hortensis hortensis Ficalbi, 1889; Cx. territans Walker, 1856 and Coquillettidia richardii Ficalbi, 1889. Among the 24893 individuals examined in 2011, Cx. pipiens sl and Cx. torrentium represent 68.00% and 22.38% respectively of total harvest. These last species with Cs. annulata, are dominants and ubiquitous in all the horse farms visited. The species of the genus Anopheles have strong ecological requirements and are therefore associated with some special habitats; other species however have a strong ability to adapt and therefore attend a wide variety of biotopes (Cx. pipiens, Cx. torrentium and Cs. annulata). At the horse farms, water troughs and ponds are the most favorable habitats for larval development of Culicidae. The species potentially vectors of arboviruses that can cause problems in epidemiological equestrian farms are Cx. pipiens sl, Cx. torrentium and Cs. annulata. [less ▲]

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See detailLaboratory and field preliminary tests of Metarhizium anisopliae formulated with neem oil (Suneem) against Anopheles gambiae sl adult emergence
Seye, Fawrou; NDIONE, Raymond; Touré, Mamour et al

Poster (2012, October 08)

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Peer Reviewed
See detailLaboratory and field preliminary tests of Metarhizium anisopliae formulated with neem oil (Suneem) against Anopheles gambiae sl adult emergence
Seye, Fawrou; Ndione, Raymond; Touré, Mamour et al

Poster (2012, October 08)

Metarhizium anisopliae have shown great potential for the control of malaria vectors. However, their ability to control aquatic stages of anopheline vectors with conidial formulation is need. In ... [more ▼]

Metarhizium anisopliae have shown great potential for the control of malaria vectors. However, their ability to control aquatic stages of anopheline vectors with conidial formulation is need. In laboratory condition (25°C and 76%RH), we formulated M. anisopliae with emulsifian neem oil (Suneem 1%) before application on An. gambiae larvae at 4, 6, 8, 10 and 12 % (v/v) to determine the LD90. We applied in semi-field environment, the LD90 of the formulation into artificial vats on the Anopheles gambiae sl larvae collected from many breeding sites at dry and rain seasons. In laboratory condition, the LD 50 was 4.4 x 10^6 spores/ml and the LD90 was not obtained 24 after exposure. The probite line equation was Y=1.61 x – 0.55 and R²= 0.9793. The LD 50 was 3.1 x 10^6 and the LD90 was 5.3 X 10^6 spores/ml 48 h after exposure. The probite line equation was then Y= 1.69 x + 1.79 and R²= 0.9757. Microscope magnifying revealed also the fungal attack via cuticle and mycelia germination one dead larvae and pupae. In semi-field environment, treatment revealed that, at 5.3 x 10^6 spores/ml, the formulation has a great emergence inhibition of mosquito adult formation. No significant difference was observed between dry and rain season application of M. anisopliae on the larvae. Therefore, a combination of M. anisopliae with Suneem may provide a more sustainable management strategy for malaria vectors control at the larval stages. [less ▲]

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See detailEtude de trois souches entomopathogènes de champignons Hyphomycètes dans la lutte contre les moustiques (Diptères : Culicidae)
Bawin, Thomas ULg

Master's dissertation (2012)

Mosquitoes (Diptera: Culicidae) are zoonotic vectors of medical and veterinary importance. The prospects for the use of three Hyphomycetes fungi (Aspergillus clavatus Desm., Metarhizium anisopliae (Metsch ... [more ▼]

Mosquitoes (Diptera: Culicidae) are zoonotic vectors of medical and veterinary importance. The prospects for the use of three Hyphomycetes fungi (Aspergillus clavatus Desm., Metarhizium anisopliae (Metsch.) Sorokin, and Metarhizium sp.) towards an important vector species (Culex quinquefasciatus Say) are discussed. 1. Culture tests were performed in flasks to assess the spore productivity of the fungal strains on wheat bran (an agricultural by-product) and husked rice (a food product that is classically used) in solid, semi-solid and liquid-state media. Regardless of the substrate, solid-state media showed the highest productivity. The observations suggested that culture tests could be carried out in solid-state or sequential fermentation with wheat bran. 2. Classical toxicity tests using aqueous suspensions of spores were performed to assess their larvicidal potential against C. quinquefasciatus. The LD50 and LD90 were estimated after 72 hours of treatment with 1.35 x 10^8 and 5 x 10^8 spores/ml for Aspergillus clavatus, 1.3 x 10^8 and 4 x 10^8 spores/ml for Metarhizium anisopliae, 1.75 x 10^8 and 9.9 x 10^8 spores/ml for Metarhizium sp. Mycelial filaments appeared from dead larvae and produced spores in the case of each strain. Spores were also found in the gut of emerged adults from surviving larvae. In comparison, the LC50 and LC90 of a commercial formulation based on the bacterium Bacillus thuringiensis var. israelensis (Vectobac ®, serotype H14) were estimated after 48 hours to 0.043 mg/l and 0.115 mg/l. The results showed that the fungi tested cannot be effective control agents at the tested doses and the applied protocol. Different axes of research are suggested. 3. The potentialities of the injection of spore suspensions into mosquito larvae in order to assess their pathogenicity have been considered. The percentages of corrected mortality were obtained after 72 hours for Aspergillus clavatus (62%), Metarhizium anisopliae (53%) and Metarhizium sp. (57%). Additional experiments would be needed to make sure whether it is well a direct response linked to the toxic effect of these fungi. 4. Optical and electron microscopy observations were conducted to study the mode of action of A. clavatus on C. quinquefasciatus larvae. Histological sections revealed that the lethal effect observed in toxicity tests is due to the ingestion of spores. An analysis of toxins produced at the beginning of germination, their contribution to larval mortality and their impact on non-target organisms should be carried out. 5. Finally, the specificity of the pathogenicity of A. clavatus and M. anisopliae against mosquitoes has been evaluated by considering another biological model: the aphid Acyrthosiphon pisum Harris. No link between the range of tested doses and (1) mortality of adults, (2) the decline of their offspring was found. Additional experiments should be carried out. The application of these fungi to other insects of agricultural, veterinary or medical interest should also be tested. [less ▲]

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See detailPathogenicity test of the fungus Aspergillus clavatus on aphid Acyrthosiphon pisum (Aphididae)
Seye, Fawrou; Bawin, Thomas ULg; Delvigne, Frank ULg et al

Poster (2012, August 19)

Pea aphid is a pest of many cultivated and wild plants, but also a vector of several viral diseases. To control this pest, the most widely used methods are physical, chemical and more recently an ... [more ▼]

Pea aphid is a pest of many cultivated and wild plants, but also a vector of several viral diseases. To control this pest, the most widely used methods are physical, chemical and more recently an integrated approach that includes biological control. With the use of pathogenic agents against insects, the use of entomopathogenic fungi is one of the most promising. The present study demonstrated the possibility of using an entomopathogenic fungus Aspergillus clavatus against aphids. In laboratory conditions (8/16 photoperiod, average temperature 25°C), the insects were in contact with different concentrations ranging from 10^2 to 10^4 spores/cm2 deposited on filter paper in Petri dishes, or applied directly to young plants with doses ranging from 10^4 to 10^6 spores/ml. In 24 hours, mortality was 0 to 31.5% in Petri dishes. For treatment plants, the cumulative mortality in 5 days was 55 to 79%. Microscopic observations showed that the aphids were infected by contact and fungus has a mycosis effect. From these preliminary results, investigations should be made to study the action of the fungus on the reproduction of aphids. Therefore, A. clavatus could be introduced along with other fungi found in the literature as a biological control agent against aphids. [less ▲]

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