Doctoral thesis (Dissertations and theses)
Contribution to the study of semiochemical slow-release formulations as biological control devices
Heuskin, Stéphanie
2011
 

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Keywords :
semiochemicals; alginate; biological control; formulation; slow-release; Fast GC; GC-MS; aphids; predators; parasitoids
Abstract :
[en] Semiochemicals – informative molecules used in insect-insect or plant-insect interactions – have been widely considered within various integrated pest management (IPM) strategies. In the present thesis, two sesquiterpenoids, E-β-farnesene and E-β-caryophyllene, were formulated for their related properties as aphid enemy attractants. E-β-farnesene, the alarm pheromone of many aphid species, was also identified as a kairomone by attracting and inducing oviposition of aphid predators (Episyrphus balteatus De Geer (Diptera: Syrphidae)) and by attracting aphid parasitoids (Aphidius ervi Haliday (Hymenoptera: Braconidae)). E-β-caryophyllene was identified as a potential component of the aggregation pheromone of the Asian ladybird, Harmonia axyridis Pallas, another aphid predator. The two products were purified from essential oils of Matricaria chamomilla L. (Asteraceae) and Nepeta cataria L. (Lamiaceae) for E-β-farnesene and E-β-caryophyllene, respectively. Natural and biodegradable slow-release formulations were then investigated in order to deliver these molecules on crop fields for a long period of time as biological control devices. Due to their sensitivity to oxidation, both sesquiterpenes needed to be protected from oxygen degradation. For this purpose, alginate – hydrophilic matrix with low oxygen permeability – was used as polymer for the formulations: the main objective was to deliver semiochemical substances in the air in a controlled way. Consequently, a careful selection of alginates was realised. Formulated beads showed different structural and encapsulation properties depending on various formulation factors. Alginate formulations were characterized by texturometry and by confocal microscopy in order to observe the distribution of semiochemicals in alginate network. The last step of alginate bead characterisation consisted in studying release rate of semiochemicals in laboratory-controlled conditions by optimised trapping and validated Fast-GC procedures. Finally, the efficiency of formulations as aphid predator (Syrphidae) and parasitoids (A. ervi) attractants was demonstrated by field trapping and olfactometry experiments.
Disciplines :
Environmental sciences & ecology
Entomology & pest control
Chemistry
Author, co-author :
Heuskin, Stéphanie ;  Université de Liège - ULiège > Chimie et bio-industries > Chimie analytique
Language :
English
Title :
Contribution to the study of semiochemical slow-release formulations as biological control devices
Defense date :
16 May 2011
Number of pages :
224
Institution :
ULiège - Université de Liège
Degree :
Docteur en sciences agronomiques et ingénierie biologique
Promotor :
Lognay, Georges ;  Université de Liège - ULiège > Département des sciences et gestion de l'environnement (Arlon Campus Environnement) > Surveillance de l'environnement
President :
Sindic, Marianne  ;  Université de Liège - ULiège > Département GxABT > Chimie des agro-biosystèmes
Secretary :
Barthelemy, Jean-Paul ;  Université de Liège - ULiège > Département GxABT > Chimie des agro-biosystèmes
Jury member :
Haubruge, Eric  ;  Université de Liège - ULiège > GxABT : Services généraux du site > Site GxABT - Cabinet du Vice-recteur
Wathelet, Jean-Paul ;  Université de Liège - ULiège > Département GxABT > Chimie des agro-biosystèmes
Bera, François ;  Université de Liège - ULiège > Département GxABT
Thonart, Philippe ;  Université de Liège - ULiège > Département GxABT > Microbial, food and biobased technologies
Hance, Thierry
Mestdagh, Michèle
Name of the research project :
SOLAPHID
Funders :
DGTRE - Région wallonne. Direction générale des Technologies, de la Recherche et de l'Énergie [BE]
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since 13 April 2011

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