title: Response of economically important aphids to components of Hemizygia petiolata essential oil.
abstract: The essential oil of Hemizygia petiolata Ashby (Lamiaceae) contains high levels (>70%) of the sesquiterpene (E)-beta-farnesene, the alarm pheromone for many economically important aphid species. In order to test the suitability of H. petiolata oil as a source of (E)-beta-farnesene for use in new integrated aphid control strategies, behavioural responses of pest aphid species were studied in laboratory and field experiments. In alarm pheromone assays the peach-potato aphid, Myzus persicae Sulzer, and the pea aphid, Acyrthosiphon pisum (Harr), showed a lower level of response to the oil than expected given the high levels of (E)-beta-farnesene. It was shown that minor components in the oil, (+)-bicyclogermacrene and (-)-germacrene D, caused inhibition of the alarm response for M. persicae and A. pisum respectively. Nevertheless, in olfactometer studies the oil was directly repellent to A. pisum and the grain aphid, Sitobion avenae F. Sitobion avenae was not only repelled by (E)-beta-farnesene but also by (-)-germacrene D. Furthermore, although it was not directly repellent to M. persicae, the oil interfered with its attraction to host plant stimuli. In field plot experiments, numbers of A. pisum were significantly reduced in plots treated with a slow release formulation of the oil, when compared with control plots.
authors.affiliation: Rothamsted Research, Harpenden, Hertfordshire, UK.
authors.forename: Toby Ja
authors.initials: TJ
authors.lastname: Bruce
authors.forename: Michael A
authors.initials: MA
authors.lastname: Birkett
authors.forename: James
authors.initials: J
authors.lastname: Blande
authors.forename: Antony M
authors.initials: AM
authors.lastname: Hooper
authors.forename: Janet L
authors.initials: JL
authors.lastname: Martin
authors.forename: Bhupinder
authors.initials: B
authors.lastname: Khambay
authors.forename: Ian
authors.initials: I
authors.lastname: Prosser
authors.forename: Lesley E
authors.initials: LE
authors.lastname: Smart
authors.forename: Lester J
authors.initials: LJ
authors.lastname: Wadhams
mesh_terms: D000818:Animals; D001042:Aphids / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects; D007302:Insect Repellents / Q000737:chemistry / Q000494:pharmacology; D019686:Lamiaceae / Q000737:chemistry*; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D010675:Pheromones / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D007302:Insect Repellents; D009822:Oils, Volatile; D010675:Pheromones; D010938:Plant Oils