title: Optimisation of a semiochemical slow-release alginate formulation attractive towards Aphidius ervi Haliday parasitoids.
abstract: BACKGROUND
  Optimisation of alginate formulations is described in order to develop semiochemical (E-β-farnesene and E-β-caryophyllene) slow-release devices in biological control approaches by attracting predators and parasitoids of aphids. Various formulation criteria were optimised with respect to semiochemical encapsulation capacity. Moreover, the optimised formulation was characterised by texturometry and confocal microscopy. The slow-release rates of semiochemicals were calculated in laboratory controlled conditions. The attractiveness of semiochemical formulations towards Aphidius ervi was demonstrated by olfactometry.
  
  
  RESULTS
  Two major parameters were highlighted in encapsulation optimisation: the type of alginate (Sigma L) and the type of crosslinker ion (Ca(2+)). Other formulation parameters were optimised: ionic strength (0.5 M), Ca(2+) (0.2 M) and alginate (1.5%) concentrations and the maturation time of beads in CaCl(2) solution (48 h). After physical characterisation of beads, semiochemical slow-release measurements showed that alginate formulations were efficient sesquiterpene releasers, with 503 µg of E-β-farnesene and 1791 µg of E-β-caryophyllene totally released in 35 days. The efficiency of semiochemical alginate beads as attractants for female parasitoids was demonstrated, with high percentages of attraction for semiochemical odours (88 and 90% for E-β-farnesene and E-β-caryophyllene respectively) and significant statistical results.
  
  
  CONCLUSIONS
  Semiochemical alginate beads can be considered as efficient slow-release systems in biological control. These formulations could be very useful to attract aphid parasitoids on crop fields.
authors: Department of Analytical Chemistry, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
authors: Stéphanie
authors: S
authors: Heuskin
authors: Stéphanie
authors: S
authors: Lorge
authors: Bruno
authors: B
authors: Godin
authors: Pascal
authors: P
authors: Leroy
authors: Isabelle
authors: I
authors: Frère
authors: François J
authors: FJ
authors: Verheggen
authors: Eric
authors: E
authors: Haubruge
authors: Jean-Paul
authors: JP
authors: Wathelet
authors: Michèle
authors: M
authors: Mestdagh
authors: Thierry
authors: T
authors: Hance
authors: Georges
authors: G
authors: Lognay
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000818:Animals; D001042:Aphids / Q000187:drug effects* / Q000502:physiology; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000494:pharmacology*; D005260:Female; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D010572:Pest Control, Biological; D010675:Pheromones / Q000737:chemistry / Q000494:pharmacology*; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes / Q000737:chemistry / Q000494:pharmacology; D014863:Wasps / Q000187:drug effects* / Q000502:physiology
chemical_list: D000464:Alginates; D003692:Delayed-Action Preparations; D006603:Hexuronic Acids; D010675:Pheromones; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; C010411:insect attractants; C062671:beta-farnesene; D020723:Glucuronic Acid; C024714:caryophyllene