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See detailA four-year inventory of the invasive ladybeetle Harmonia axyridis in agricultural ecosystems
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

Conference (2013, October 26)

The Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is known to thrive principally in shrubby and arboreal habitats. Its occurrence in agroecosystems remains poorly ... [more ▼]

The Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is known to thrive principally in shrubby and arboreal habitats. Its occurrence in agroecosystems remains poorly documented. This study focuses on the occurrence of this exotic species and its seasonal abundance in various field crops. The abundance of adults and larvae of H. axyridis was evaluated over a four-year period, from 2009 to 2012, in four important agronomical crops (wheat, corn, broad bean and potato) in Belgium. A total of 28 aphid predator species were observed including 14 coccinellid species, 13 hoverfly species and one lacewing species. H. axyridis is present and reproduces in all of the four crops studied, with the largest numbers recorded in corn and broad bean crops. In corn, H. axyridis numbers were found to increase over the four inventoried year, reaching 86% of the aphid predators in 2012, while it represented only 15% in 2009. H. axyridis was not always recorded where aphids were abundant, e.g. aphids were abundant on wheat where no H. axyridis were recorded. H. axyridis starts reproducing after the peak in aphid population, suggesting that H. axyridis is able to complete its development by feeding on alternative prey such as larvae and pupae of the same and other species of ladybird and other aphidophagous species. H. axyridis is often considered to be bivoltine but it only completes one generation per year in field crops. The second generation generally develops late in the season in other habitats. Harmonia axyridis is an invasive and an intraguild predator present in high quantities in some specific crops. In these crops, H. axyridis could negatively impact on population of native species due to IGP observed in several other studies. [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 detailL'entomophagie, Défis du futur ?
Caparros Megido, Rudy ULg; Francis, Frédéric ULg

Conference (2013, October 19)

En 2050, il faudra nourrir 9 milliards d¿individus sur terre, soit 1,33 fois plus qu'à l'heure actuelle. De plus, la consommation humaine devrait augmenter de 1,77 fois suite au nouveau mode de ... [more ▼]

En 2050, il faudra nourrir 9 milliards d¿individus sur terre, soit 1,33 fois plus qu'à l'heure actuelle. De plus, la consommation humaine devrait augmenter de 1,77 fois suite au nouveau mode de consommation des pays émergents. Vu la difficulté actuelle de trouver de nouvelles surfaces cultivables ou de production, d'autres alternatives sont à mettre en évidence. A l'unité d'Entomologie de Gembloux Agro-Bio Tech, nous avons décidé de développer l'entomophagie ou la consommation d'insectes par l'être humain. Plus ou moins 1500 espèces sont consommées dans le monde parmi divers ordre d'insectes dont les principaux sont les Coléoptères (30% des espèces consommées), les Lépidoptères (17%), les Hyménoptères (13%), les Orthoptères (10%) et les Hémiptères (8%). Il est légitime de se demander l'intérêt de consommer des insectes. Premièrement, ces derniers possèdent des qualités nutritionnelles remarquables (taux de protéines, d¿acide gras non saturés, de vitamines et de minéraux importants) en fonction de l'espèce-cible, de son stade de développement et de sa diète de développement. Deuxièmement, ils possèdent un meilleur taux de conversion de la nourriture que les élevages conventionnels (10 kg de fourrage donne 1kg de bœuf contre 8 kg d'insectes) et ils possèdent un faible impact environnemental (3 fois moins d'émission de gaz à effet de serre). Finalement, des études complémentaires sur la sûreté de la consommation d'insectes sont à réaliser. En effet, très peu de données sont disponibles sur les allergènes présents dans les insectes ainsi que les maladies ou parasites pouvant être transmis par le biais de leur consommation. [less ▲]

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See detailMoustiques (Diptera : Culicidae) de la région du M’Zab-Ghardaïa, Algérie : biodiversité et importance médico-vétérinaire
Boukraa, Slimane ULg; Baba Aissa, Nadir; Abdelaziz, Brahim et al

Poster (2013, October 19)

De nombreuses espèces de moustiques sont susceptibles de jouer un rôle dans la transmission de divers agents pathogènes responsables des maladies infectieuses humaines et animales. D'autres, outre leur ... [more ▼]

De nombreuses espèces de moustiques sont susceptibles de jouer un rôle dans la transmission de divers agents pathogènes responsables des maladies infectieuses humaines et animales. D'autres, outre leur rôle vecteur, sont un véritable fléau par les piqûres douloureuses qu’ils occasionnent et, constituent de ce fait un grand problème de nuisance. L'identification précise et la connaissance de la biodiversité fonctionnelle des vecteurs est un pas essentiel pour la compréhension du risque de (ré)-émergence et la dynamiques des maladies vectorielles. Le présent travail est une étude rétrospective des inventaires des Culicidae réalisés sur le terrain dans la région du M’Zab (Ghardaïa, Algérie) durant les années allant de 2008 à 2012. Les résultats de l’étude morphotaxonomique des Culicidae inventoriés ont montré la présence de dix espèces réparties en cinq genres (Culex, Culiseta, Ochlerotatus, Anopheles et Uranotaenia). Un aperçu sur le rôle vectoriel des espèces signalées dans la région et leur importance au niveau de la santé médicale et vétérinaire sont présentés à partir des données bibliographiques. Les espèces potentiellement vectrices d’arbovirus (Virus de Nile occidentale et Virus de la Vallée du Rift) et de protozoaires (Plasmodium spp) qui peuvent causer des problèmes épidémiologique au niveau de la région du M’Zab sont Cx. pipiens sl L., 1758, Cx. theileri Theobald, 1903, Ochlerotatus caspius Pallas, 1771, Anopheles sergentii Theobald, 1907, An. dthali Patton, 1905 et An. multicolor Cambouliu, 1902. [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 detailAre bogs reservoirs for emerging disease vectors? Evaluation of Culicoides populations in the Hautes Fagnes Nature Reserve (Belgium)
Zimmer, Jean-Yves ULg; Losson, Bertrand ULg; Smeets, François ULg et al

Poster (2013, October)

Several species of Culicoides (Diptera: Ceratopogonidae) biting midges serve as biological vec{ors for the bluetongue virus (BTV) and the recently described Schmallenberg virus in northern Europe. since ... [more ▼]

Several species of Culicoides (Diptera: Ceratopogonidae) biting midges serve as biological vec{ors for the bluetongue virus (BTV) and the recently described Schmallenberg virus in northern Europe. since their recent emergence in this part of the continent, these diseases have caused considerable economic losses to the sheep and cattle industries. Much data is nou, âvailable that describe the distribuüon, population dynamics, and feeding habits of these insects. However, little is known regarding the presence of culicoides in unusual habitats such as peaÿ marshes, nor their potential vector capacity. This study evaluated Culicoides biting midges present in the bogs of a Belgian nature reserve compared to those residing at a nearby cattle farm. Culicoides were trapped in 2011 at four different sites (broadleaved and coniferous forested areas, open environments, and at a scientific station) located in the Hautes Fagnes Nature Reserve (Belgium). An additional light trap was operated on a nearby caftle farm. High numbers of biting midges were captured in the marshy area and most of them were Culicoides impunc{atus, a potential vector of BïV and other pâthogens. ln addition, fewer numbers of c. obsoletus/c. scoticus species, C. chiopterus, and C. dewulfi were observed in the bogs compared to the farm. The wet environment and oligotrophic nature of the soil were probably responsible for these changes in the respective populations. A total of 297,808 Culicoides midges belonging to 27 species were identified during this study and 3 of these species (C. sphagnumensis, C. clintoni and C. comosioculatus) were described in Belgium for the first time. [less ▲]

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See detailFirst Evidence of a Volatile Sex Pheromone in Harmonia axyridis (Pallas)
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

Poster (2013, October)

Until now, no volatile sex pheromone has been highlighted in Coccinellidae but various studies have suggested the existence of such molecules. In the present work, we have sampled volatile organic ... [more ▼]

Until now, no volatile sex pheromone has been highlighted in Coccinellidae but various studies have suggested the existence of such molecules. In the present work, we have sampled volatile organic compounds released in the headspace of virgin females in the multicolored Asian ladybeetle, Harmonia axyridis (Pallas), that were either allowed or not to feed on pea aphids (Acyrthosiphon pisum Harris). When fed on aphids, virgin females showed a stereotypical “calling behavior”, commonly associated with the emission of a sex pheromone in several Coleoptera species. Behavioral assays conducted with calling females in a four-arm olfactometer demonstrated that the blend of released volatile compounds was attractive at a distance for males, but not for other females. The headspace of virgin females that were not previously fed with aphids was not attractive for either sex. GC-MS analyses revealed the presence of five compounds in the volatile blend: (–)-β-caryophyllene, β-elemene, methyl-eugenol, α-humulene and α-bulnesene. Subsequently, we have collected and quantified the constituents from the blend over a period of 9 days after exposure to aphids. All five compounds were produced exclusively after feeding virgin females with aphids, and their quantity significantly increased during the whole period of collection. (–)-β-caryophyllene was found to be the major constituent, representing between 80 and 86 % of the total blend. All these results could promote the development of more specific and efficient management methods to manipulate the movements of this invasive ladybeetle and to reduce its negative impacts on biodiversity. [less ▲]

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See detailCrop association to improve biological control: case study on pea and wheat aphids
Chevalier Mendes Lopes, Thomas ULg; Bodson, Bernard ULg; Francis, Frédéric ULg

Conference (2013, September 13)

Nowadays, strategies used to control aphids in fields of pea, Pisum sativum L., and wheat, Triticum aestivum L., still rely on synthetic insecticides which have negative effects on the environment and ... [more ▼]

Nowadays, strategies used to control aphids in fields of pea, Pisum sativum L., and wheat, Triticum aestivum L., still rely on synthetic insecticides which have negative effects on the environment and human health. This research focused on the development of sustainable alternative methods, with special emphasis on cultural practices and plant management systems. Increasing the diversity within crops may have several beneficial effects on pest control, creating attractive habitats for indigenous beneficial fauna and simultaneously deterring pests – the ‘push-pull’approach. In this field study, two wheat/pea associations (mixed cropping and strip cropping) where compared to monocultures of pea and wheat. The abundance and diversity of adult aphidophagous insects (predators and parasitoids) were accessed weekly using yellow traps, while aphids were observed directly on plants. In both crops, the percentage of plants infested with aphids and density of aphid colonies were significantly higher in monocultures during periods of aphid abundance. Mixed cropping was particularly beneficial for the pea, whereas strip-cropping was more efficient for the wheat. The abundance of beneficials was significantly higher in monocultures comparing to the other treatments. Quantitative aphid-natural enemy food webs showed that the abundance of the two main ladybird species, Coccinella septempunctata L. and Propylea quatuordecimpunctata (L.), increased with the occurrence of Acyrthosiphon pisum (Harris) on pea plants. Abundance of the two main species of Syrphidae, Sphaerophoria scripta (L.) and Eupeodes corollae (F.), increased with the occurrence of Sitobion avenae (F.) and Metopolophium dirhodum (Walker) on wheat plants. This study shows that increasing diversity within crops can help lower aphid infestations. However, additional methods are needed to more efficiently attract aphidophagous beneficials and promote the natural control of aphids. [less ▲]

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See detailThe Multicoloured Asian Ladybird, invasive or not in agroecosystems ?
Vandereycken, Axel ULg; Durieux, Delphine ULg; Fassotte, Bérénice ULg et al

Poster (2013, September 10)

The Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is known to thrive principally in shrubby and arboreal habitats. Its occurrence in agroecosystems remains poorly ... [more ▼]

The Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is known to thrive principally in shrubby and arboreal habitats. Its occurrence in agroecosystems remains poorly documented. This study focuses on the occurrence of this exotic species and its seasonal abundance in various field crops. The abundance of adults and larvae of H. axyridis was evaluated over a four-year period, from 2009 to 2012, in four important agronomical crops (wheat, corn, broad bean and potato) in Belgium. A total of 28 aphid predator species were observed including 14 coccinellid species, 13 hoverfly species and one lacewing species. H. axyridis is present and reproduces in all of the four crops studied, with the largest numbers recorded in corn and broad bean crops. In corn, H. axyridis numbers were found to increase over the four inventoried year, reaching 86% of the aphid predators in 2012, while it represented only 15% in 2009. H. axyridis was not always recorded where aphids were abundant, e.g. aphids were abundant on wheat where no H. axyridis were recorded. H. axyridis starts reproducing after the peak in aphid population, suggesting that H. axyridis is able to complete its development by feeding on alternative prey such as larvae and pupae of the same and other species of ladybird and other aphidophagous species. H. axyridis is often considered to be bivoltine but it only completes one generation per year in field crops. The second generation generally develops late in the season in other habitats. Harmonia axyridis is an invasive and an intraguild predator present in high quantities in some specific crops. In these crops, H. axyridis could negatively impact on population of native species due to IGP observed in several other studies. [less ▲]

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See detailProteomic Investigation of Aphid Honeydew Reveals an Unexpected Diversity of Proteins
Sabri, Ahmed; Vandermoten, Sophie ULg; Leroy, Pascal et al

in PLoS ONE (2013), 8(9),

Aphids feed on the phloem sap of plants, and are the most common honeydew-producing insects. While aphid honeydew is primarily considered to comprise sugars and amino acids, its protein diversity has yet ... [more ▼]

Aphids feed on the phloem sap of plants, and are the most common honeydew-producing insects. While aphid honeydew is primarily considered to comprise sugars and amino acids, its protein diversity has yet to be documented. Here, we report on the investigation of the honeydew proteome from the pea aphid Acyrthosiphon pisum. Using a two-Dimensional <br />Differential in-Gel Electrophoresis (2D-Dige) approach, more than 140 spots were isolated, demonstrating that aphid honeydew also represents a diverse source of proteins. About 66% of the isolated spots were identified through mass spectrometry analysis, revealing that the protein diversity of aphid honeydew originates from several organisms (i.e. the host aphid and its microbiota, including endosymbiotic bacteria and gut flora). Interestingly, our experiments also allowed to identify some proteins like chaperonin, GroEL and Dnak chaperones, elongation factor Tu (EF-Tu), and flagellin that might act as mediators in the plant-aphid interaction. In addition to providing the first aphid honeydew proteome analysis, we propose to reconsider the importance of this substance, mainly acknowledged to be a waste product, from the aphid <br />ecology perspective. [less ▲]

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Peer Reviewed
See detailInteractions of two aphid species on the african eggplant, sorrel and amaranth
Bayendi-Loudit, Sandrine ULg; Chevalier Mendes Lopes, Thomas ULg; Francis, Frédéric ULg

Poster (2013, September)

Aphids (Homoptera: Aphididae) are polyphagous insects which can be found on several crops in temperate zones, as well as in the tropics. The multiplication of Aphis gossypii Glover (C9 cucumber, Burk ... [more ▼]

Aphids (Homoptera: Aphididae) are polyphagous insects which can be found on several crops in temperate zones, as well as in the tropics. The multiplication of Aphis gossypii Glover (C9 cucumber, Burk cotton and Pipo pepper strains) and Myzus persicae Sulzer was studied in the laboratory on three plant species: African eggplant, Solanum aethiopicum, sorrel, Hibiscus sabdariffa, and amaranth, Amaranthus spp. Periodic counts were carried out to monitor population growth. The multiplication rate of M. persicae wass higher than that of A. gossypii when these two species were present together on eggplant. Amaranth was less suitable for the development of both species, but Myzus persicae again had a better multiplication rate than Aphis gossypii. This study illustrated the importance of considering not only one pest species, but the whole herbivore guild, especially when biological control is important. [less ▲]

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