title: A host-plant-derived volatile blend to attract the apple blossom weevil Anthonomus pomorum - the essential volatiles include a repellent constituent.
abstract: BACKGROUND
  Plant volatiles are promising cues for trapping pest insects. This study started with a recently identified complex blend released by prebloom apple trees and aimed to reduce the number of compounds in the blend while maintaining the attraction of the target pest, the apple blossom weevil Anthonomus pomorum. An evaluation was made to determine whether attraction to plant volatiles is a general feature in this species.
  
  
  RESULTS
  Laboratory-based bioassays with field-collected weevils demonstrated repellency by volatiles from the non-host walnut, indicating that preference for plant odours is not a general feature in this species. By a subtractive bioassay approach, the original number of compounds in the apple-plant-released blend was stepwise reduced from 12 to 6 while maintaining weevil attraction. This resulting blend was as attractive as the full blend and as a blossom-bud-carrying apple twig. It was found to be composed of two synergistically interacting constituents, of which the first containing benzenoids was behaviourally inactive, and the second comprising the remaining compounds was even repellent.
  
  
  CONCLUSIONS
  This study enhances knowledge of the interaction of behaviourally effective constituents in complex odour blends and contributes to the development of an efficient monitoring system involving plant volatiles for the apple blossom weevil.
authors: ETH Zurich, Institute of Agricultural Sciences/Applied Entomology, Zurich, Switzerland.
authors: Jana
authors: J
authors: Collatz
authors: Silvia
authors: S
authors: Dorn
mesh_terms: D000818:Animals; D001681:Biological Assay; D005260:Female; D005638:Fruit / Q000737:chemistry* / Q000378:metabolism; D007302:Insect Repellents / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D007306:Insecticides / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D027845:Malus / Q000737:chemistry* / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D048889:Weevils / Q000187:drug effects* / Q000502:physiology*
chemical_list: D007302:Insect Repellents; D007306:Insecticides; D055549:Volatile Organic Compounds
keywords: Anthonomus pomorum; Curculionidae; apple; host location; olfaction; synergism