References of "Verheggen, François"
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See detailConservation value of protected and logged tropical forests in Cameroon
Lhoest, Simon ULiege; Fonteyn, Davy ULiege; Daïnou, Kasso ULiege et al

Scientific conference (2019, January 25)

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See detailAlternatives to neonicotinoids
Jactel, Hervé; Verheggen, François ULiege; Thiery, Denis et al

in Environment International (2019), 129

The European Food Safety Authority concluded in February 2018 that “most uses of neonicotinoid insecticides represent a risk to wild bees and honeybees”. In 2016, the French government passed a law ... [more ▼]

The European Food Safety Authority concluded in February 2018 that “most uses of neonicotinoid insecticides represent a risk to wild bees and honeybees”. In 2016, the French government passed a law banning the use of the five neonicotinoids previously authorized: clothianidin, imidacloprid, thiamethoxam, acetamiprid and thiacloprid. In the framework of an expert assessment conducted by the French Agency for Food, Environmental and Occupational Health and Safety to identify possible derogations, we performed a thorough assessment of the available alternatives to the five banned neonicotinoids. For each pest targeted by neonicotinoids use, we identified the main alternative pest management methods, which we then ranked for (i) efficacy for controlling the target pest, (ii) applicability (whether directly useable by farmers or in need of further research and development), (iii) durability (risk of resistance in targeted pests), and (iv) practicability (ease of implementation by farmers). We identified 152 authorized uses of neonicotinoids in France, encompassing 120 crops and 279 pest insect species (or genera). An effective alternative to neonicotinoids use was available in 96% of the 2968 case studies analyzed from the literature (single combinations of one alternative pest control method or product×one target crop plant×one target pest insect). The most common alternative to neonicotinoids (89% of cases) was the use of another chemical insecticide (mostly pyrethroids). However, in 78% of cases, at least one non-chemical alternative method could replace neonicotinoids (e.g. microorganisms, semiochemicals or surface coating). The relevance of non-chemical alternatives to neonicotinoids depends on pest feeding habits. Leaf and flower feeders are easier to control with non-chemical methods, whereas wood and root feeders are more difficult to manage by such methods. We also found that further field studies were required for many promising non-chemical methods before their introduction into routine use by farmers. Our findings, transmitted to policymakers, indicate that non-chemical alternatives to neonicotinoids do exist. Furthermore, they highlight the need to promote these methods through regulation and funding, with a view to reducing pesticide use in agricultur [less ▲]

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See detailFirst record of Tuta absoluta in Haiti
Verheggen, François ULiege; Fontus, Bertin

in Entomologia Generalis (2019)

From March to June 2018, we performed an insect survey in four tomato fields located in the South Department of Haiti. Although crop rotations and insecticide applications are regularly performed on these ... [more ▼]

From March to June 2018, we performed an insect survey in four tomato fields located in the South Department of Haiti. Although crop rotations and insecticide applications are regularly performed on these fields, insect pests repeatedly cause damage to plants and fruits. Leafminer larvae and adults were captured and further identified as Tuta absoluta Meyrick (Lepidoptera: Gelechiidae). This is the first record of this important tomato pest in Haiti. Early conversations with growers suggest that the insect is experiencing a year of unprecedented outbreaks. We expect growers to increase the frequency and doses of insecticide treatments, accelerating the development of insecticide resistant populations. The presence of T. absoluta in Haiti will probably result in a fast expansion to the neighbouring Dominican Republic, and could serve as additional reservoir for dissemination to American countries. [less ▲]

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See detailThe taste of origin in a lady beetle: do males discriminate between females based on cuticular hydrocarbons?
Legrand, Pauline; Vanderplanck, Maryse; Marko, Istvan et al

in Physiological Entomology (2019)

The Asian lady beetle Harmonia axyridis originates from Asia and has established invasive populations at a worldwide scale. Recent population genetic studies have traced their invasion routes and ... [more ▼]

The Asian lady beetle Harmonia axyridis originates from Asia and has established invasive populations at a worldwide scale. Recent population genetic studies have traced their invasion routes and demonstrated that bottlenecks in population size have reduced their genetic diversity. As a consequence, phenotypical differences were highlighted between native and invasive populations. Among phenotypical traits, cuticular hydrocarbons (CHCs) might reflect geographical origin of a lady beetle, especially because of their genetic basis. Here, we investigated whether (i) the CHC profiles qualitatively and quantitatively differ between females of H. axyridis from native and invasive populations; and (ii) males discriminate females from native and invasive populations using CHC profiles. CHCs were solvent-extracted before being quantified and identified by gas chromatography and mass spectrometry. We detected a total of 17 CHCs from female elytra including six alkanes, three polyunsaturated and eight monounsaturated alkenes. The total quantity of CHCs differed among the populations with lady beetles from Tai’an (China) displaying a higher CHCs concentration than lady beetles from Gembloux (Belgium) and from Beijing (China) populations. Multivariate analyses detected differences in CHCs qualitative profiles, with females from Tai’an being different from the two other populations. Finally, our behavioural assays showed that females originating from the native Tai’an population were less preferred by males, while females from the invasive population were mounted more often. Our behavioural assays suggest that CHCs are not involved in discrimination of mating partners based on their origin. [less ▲]

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See detailCuticular hydrocarbon composition does not allow Harmonia axyridis males to identify the mating status of sexual partners
Legrand, Pauline; Vanderplanck, Maryse; Lorge, Stéphanie ULiege et al

in Entomologia Generalis (2019), 38(3), 211-224

Males of polyandrous species have to overcome sperm competition. They should select their mate based on the reproductive status of the female to increase their own fitness. Because the sexual behavior of ... [more ▼]

Males of polyandrous species have to overcome sperm competition. They should select their mate based on the reproductive status of the female to increase their own fitness. Because the sexual behavior of lady beetles relies on semiochemicals, with cuticular hydrocarbons (CHCs) being used for mate recognition, we developed and tested two hypotheses. First, we hypothesized that the cuticular hydrocarbon profile qualitatively and quantitatively differs between virgin and mated Harmonia axyridis females, regardless of the color morph. Second, we hypothesized that males discriminate virgin and mated females, preferring copulating with virgin females, rather than previously mated ones, to avoid sperm competition and subsequently increase their fitness. CHCs were solvent-extracted before being quantified and identified by gas chromatography. We found no qualitative differences between mated and unmated females irrespective of the morph; however, quantitative differences were detected. Specifically, the CHC profiles of mated females presented higher concentrations of alkenes, including 9-pentacosene, 9-heptacosene, and 9-hentriacontene. During dual-choice behavioral assays, males equally copulated with virgin and mated females. Our results suggest that there is no CHC-based discrimination strategy in virgin males of H. axyridis between virgin and once-mated females. We discuss alternative strategies that might be used in this lady beetle species. [less ▲]

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See detailImpact of necrophagous insects on the emission of volatile organic compounds released during the decaying process
Martin, Clément ULiege; Vanderplanck, Maryse; Boullis, Antoine ULiege et al

in Entomologia Generalis (2019), 39(1),

After death, corpses undergo a complex decomposition process, during which volatile organic compounds (VOCs) are released. Several groups of organisms, including insects, use these VOCs to select their ... [more ▼]

After death, corpses undergo a complex decomposition process, during which volatile organic compounds (VOCs) are released. Several groups of organisms, including insects, use these VOCs to select their mating and feeding sites. While the presence of insects on a corpse influences the decaying process, we do not know whether insects impact on the VOC profile released by the cadaver. Using decomposing rats exposed to dipterans (Lucilia sericata) and/or coleopterans (Dermeste frischii), we assessed how the presence of insects impacted the cadaver volatilome by using dynamic sampling. As expected, the decomposition of rats in presence of insects was faster than in absence of insects. All rats went through the five decomposition stages with the exception of rats decomposing without insects. The composition of their volatile profiles differed among decomposition stages. We also found that insects do not affect the volatilome of decomposing rats, and no indicator compound could be associated to the presence of specific insect groups [less ▲]

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See detailBiological alternatives to pesticides to control wireworms (Coleoptera: Elateridae)
La Forgia, Diana ULiege; Verheggen, François ULiege

in Agri Gene (2019), 11

Most studies on plant-insect interactions focus on the aboveground parts of plants, but the knowledge regarding the belowground interactions is increasing. Soil pests are at least equally dangerous to ... [more ▼]

Most studies on plant-insect interactions focus on the aboveground parts of plants, but the knowledge regarding the belowground interactions is increasing. Soil pests are at least equally dangerous to plant health and elicit plant defense mechanisms as well. Wireworms (Coleoptera: Elateridae) are common polyphagous soil pests of various crops, including economically relevant crops such as maize and potatoes. Their management with pesticides is often not successful or sustainable, and more research on biological alternatives is required. We aim at providing an overview of biological control methods under development or commercially available. Little is known about the natural enemies of wireworms, and the available work is often limited to laboratory experiments. The interest for using using microorganisms as biocontrol agent is increasing, and entomopathogenic fungi, nematodes, and bacteria represent promising alternatives to pesticides. The review discusses the combination of attractive semiochemicals with biological agents to improve wireworm monitoring and control, as well as research advances on these fronts [less ▲]

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See detailToday and tomorrow: impact of climate change on aphid biology and potential consequences on their mutualism with ants
Blanchard, Solène ULiege; Lognay, Georges ULiege; Verheggen, François ULiege et al

in Physiological Entomology (2019)

Recent studies about mutualism are considering the complexity and versatility of the relation as well as highlighting the importance of the cost/benefit balance between the two protagonists. As species ... [more ▼]

Recent studies about mutualism are considering the complexity and versatility of the relation as well as highlighting the importance of the cost/benefit balance between the two protagonists. As species interactions are highly dependent on the environment, the climate changes that are foreseen for the coming years, are expected to have significant impacts on the evolution of mutualistic interactions. Among mutualisms, the aphid-ant interaction is well documented, partly explained by the pest status of aphids. This literature review focuses on the impact of climate change (particularly atmospheric carbon dioxide concentration and temperature) on aphids’ biology and the potential consequences on their mutualistic interactions with ants. We provide an overview of the published reports that deal with the effects of temperature and carbon dioxide on aphids, for which a positive, a negative or a no-effect was highlighted. A discussion is then provided on how climatic changes can alter four major components of aphid biology that are shaping their interaction with ants: (1) aphid population growth, (2) aphid behavior and mobility, (3) honeydew production and composition, and (4) semiochemistry. At the end of the review, we discuss limits to such studies on aphid-ant mutualism as well as the information still needed to predict how climate change might impact this kind of relationship. [less ▲]

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See detailThe walnut husk fly invades Europe: Risk analysis and development of a biological control strategy
Verheggen, François ULiege

Conference (2018, November 07)

Rhagoletis completa is a fly native to California that invaded Western Europe in the late 1980s. The fly was initially identified in Switzerland (1988) and Italy (1991), from where it spread to at least ... [more ▼]

Rhagoletis completa is a fly native to California that invaded Western Europe in the late 1980s. The fly was initially identified in Switzerland (1988) and Italy (1991), from where it spread to at least seven additional countries (France, Spain, Germany, Austria, Croatia, Slovenia and Hungary). Rhagoletis completa has not reached the limits of its potential distribution. Walnut trees are widely distributed in Europe favouring the probability of fly establishment in currently fly-free areas. Since its introduction in Europe, it causes important damage to walnuts. In orchards where Rhagoletis completa is present and uncontrolled, 100% of walnut trees can be infested, causing losses in walnut yields of up to 80%. The negative effect is low (<10% yield loss) under phytosanitary control, although additional costs must also be considered to support specific monitoring for Rhagoletis completa. Europe aims at reducing the amount of phytosanitary products in its territory (e.g. Directive 2009/128/CE), resulting in the necessity to develop environment-friendly methods of pest control. After a 4-year research project conducted jointly in Gembloux Agro-Bio tech (Belgium) and in Chatte (France), we have proposed a new biological method to monitor and control walnut husk flies in walnut orchards. This pheromone-based control strategy is currently being tested in the field, thank to a close association with an industrial partner. This pesticide-free biological product should allow a reduction of the damages caused by the walnut husk fly. [less ▲]

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See detailForêts, services écosystémiques et produits forestiers non-ligneux
Verheggen, François ULiege; Lhoest, Simon ULiege; Hette, Samuel et al

Learning material (2018)

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See detailImpact of entomopathogenic fungi on multitrophic insect-plant interactions
Fingu Mabola, Junior ULiege; Lognoul, Marine; Bosquée, Emilie et al

Poster (2018, August 18)

Entomopathogen microorganisms such as fungi are biological control agents that are able to disturb host plant – herbivore relations due to their interactions with some target insects. Particularly, these ... [more ▼]

Entomopathogen microorganisms such as fungi are biological control agents that are able to disturb host plant – herbivore relations due to their interactions with some target insects. Particularly, these fungi grow on insect hosts, secrete secondary metabolites and finally kill them. Here, we investigated the influence of diverse entomopathogenic fungi (Beauveria, Metarhizium, Aspergillus) on different insect hosts but also on non target beneficials. Aphids and bugs for herbivore guild while aphidophagous predators for tritrophic interactions were selected respectively. Multitrophic approaches were developed to determine potential effects of these fungi on the behaviour of intra- and interguild protagonists. Beside the observation of insect developmental parameters, the orientation preferences were tested by taking into consideration the insect and/or plant fungal infection status. Olfactometry devices were used, complemented by choice tests in Petri dishes and analysis of emitted volatile organic compounds. Also, electropenetrography (EPG) technique was developed to assess the changes of aphid and bug sucking feeding behaviour related to fungal infestation status. Our results are discussed in relation to the complexity of interactions at different trophic levels, with a particular focus on behavioural more than only developmental aspects of the impact of entomopathogenic fungi in plant - insect interactions. [less ▲]

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See detailSemiochemicals to control the Walnut husk fly Rhagoletis completa
Sarles, Landry ULiege; Verhaghe, Agnès; Verheggen, François ULiege

Poster (2018, August)

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See detailSemiochemicals to control the Walnut husk fly Rhagoletis completa
Sarles, Landry ULiege; Verhaeghe, Agnès; Verheggen, François ULiege

in Crop Protection, Ghent Proceedings, May 21 2018 (2018, August)

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See detailElevated CO2 concentration impact the semiochemistry of aphid honeydew without cascade effect on an aphid predator
Blanchard, Solène ULiege; Boullis, Antoine; Detrain, Claire et al

Conference (2018, July 03)

Honeydew is now considered a cornerstone of the interactions between aphids and their natural enemies. Its composition is impacted by the aphid host plant species and associated phloem sap. Bacteria ... [more ▼]

Honeydew is now considered a cornerstone of the interactions between aphids and their natural enemies. Its composition is impacted by the aphid host plant species and associated phloem sap. Bacteria activity occurring in the aphid honeydew typically results in the release of volatile organic compounds (VOCs) that are used by aphid natural enemies for prey location. Because atmospheric carbon dioxide (CO2) concentration directly impacts plants physiology, we raise the hypothesis that elevated CO2 concentrations impact the quantity of honeydew produced by aphids, as well as the diversity and quantity of honeydew VOCs, with cascade effects on the foraging behavior of aphid natural enemies. Using solid-phase microextraction, we quantified the VOCs emitted by honeydew from pea aphids (Acyrthosiphon pisum Harris) reared either under 450 ± 50 ppm of CO2 (aCO2) or 800 ± 50 ppm of CO2 (eCO2). While the total amount of honeydew (honeydew release by 190 ± 50 individus in both conditions) is not impacted by the CO2 concentration, we found qualitative and quantitative differences in the semiochemistry of aphid honeydew between CO2 conditions. Three VOCs were not found in the honeydew of eCO2 aphids: 3-methyl-2-buten-1-ol, 2-methyl-1-butanol and isobutanol. However, no difference was observed in the searching and oviposition behavior of hoverfly (Episyrphus balteatus De Geer) females exposed to infested plants reared under both CO2 conditions, in a dual choice bioassay. The present work focuses on one particular aspect of atmospheric changes and should be extended to other abiotic parameters, such as temperature. [less ▲]

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See detailSemiochemicals to control the Walnut husk fly Rhagoletis completa
Sarles, Landry ULiege; Verhaeghe, Agnès; Verheggen, François ULiege

Conference (2018, July)

Most European walnut producers have to deal with the recent introduction of the Walnut Husk Fly, Rhagoletis completa (Diptera, Tephritidae), that causes severe economic losses, especially in biological ... [more ▼]

Most European walnut producers have to deal with the recent introduction of the Walnut Husk Fly, Rhagoletis completa (Diptera, Tephritidae), that causes severe economic losses, especially in biological productions. In orchards where R. completa is present and uncontrolled, losses in walnut yields can reach up to 80%. As a consequence, there is a need for developing environment-friendly methods of control. In this research, we evaluated the efficiency of two different semiochemical blends to trap R. completa in walnut orchards. The first semiochemical blend consisted in walnut fruit volatiles, previously collected and identified from two walnut varieties. The second semiochemical blend was made of the putative male sex pheromone, made of two lactones, and previously collected from R. completa males. In field both semiochemical blends were associated with yellow sticky traps. The assays were conducted in France, in a total of 53 orchards, in 2015, 2016 and 2017. The first blend (made of fruit kairomones) was highly attractive for both male and female R. completa in a laboratory assay, but did not enhance the number of fly captures in the field. On the other hand, sticky traps associated with the putative sex pheromone captured up to 10 times more fruit flies each week during the entire season. The total number of captured flies was also more important than with a mass trapping system baited with food attractant. These field results are promising for R. completa monitoring and mass trapping. [less ▲]

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See detailImpact of carbon dioxide concentration on the plant-aphid-natural enemies relationship
Blanchard, Solène ULiege; Detrain, Claire; Lognay, Georges ULiege et al

Conference (2018, May 22)

While the impact of climate change on plant or insect communities has been receiving increasing attention during the last decade, plant-insect interactions under a changing environment remain to be ... [more ▼]

While the impact of climate change on plant or insect communities has been receiving increasing attention during the last decade, plant-insect interactions under a changing environment remain to be studied. These interactions are of importance as regard to the economically dimension of some crop plants and the associated species of insect pests. Insect-plant interactions are mediated by plant secondary metabolites, including volatile organic compounds (VOCs). Modifications in greenhouse gases concentrations, as predicted for 2100, could alter these chemically mediated interactions. Here, we raise the hypothesis that a raise of carbon dioxide concentration (beyond 700 ppm) affects the volatile emission of Broad bean plants, with a cascade impact on insect pests and its natural enemies. For this purpose, an experiment was made to determine the impact of CO2 concentration on aphid choice for their host plant. Choice tests were made on winged aphids between two plants grown under two CO2 concentrations. Differences were found in the choice made by the aphids. We decided then to generate odour samplings on Vicia faba plants reared under the same CO2 concentrations, hypothesizing that differences in plant semiochemicals may induce preferences for aphids. No differences were found when identifying the volatile organic compounds. Because atmospheric carbon dioxide (CO2) concentration directly impacts plants physiology, we raise the hypothesis that elevated CO2 concentrations impact the quantity of honeydew produced by aphids, as well as the diversity and quantity of honeydew VOCs, with cascade effects on the foraging behavior of aphid natural enemies. Using solid-phase microextraction, we quantified the VOCs emitted by honeydew from pea aphids (Acyrthosiphon pisum Harris) reared either under 450 ± 50 ppm of CO2 (aCO2) or 800 ± 50 ppm of CO2 (eCO2). While the total amount of honeydew (honeydew release by 190 ± 50 individus in both conditions) is not impacted by the CO2 concentration, we found qualitative and quantitative differences in the semiochemistry of aphid honeydew between CO2 conditions. Three VOCs were not found in the honeydew of eCO2 aphids: 3-methyl-2-buten-1-ol, 2-methyl-1-butanol and isobutanol. However, no difference was observed in the searching and oviposition behavior of hoverfly (Episyrphus balteatus De Geer) females exposed to infested plants reared under both CO2 conditions, in a dual choice bioassay. [less ▲]

Detailed reference viewed: 71 (6 ULiège)