Abstract

The response of the bird cherry-oat aphid, Rhopalosiphum padi, to barley plants was investigated following exposure of the plants to root allelo-chemicals from the aggressive weed couch-grass, Elytrigia (Agropyron) repens. Plants were treated either with root exudates from living couch-grass plants or with previously identified couch-grass root compounds [5-hydroxyindole-3-acetic acid, DL-5-hydroxytryptophan, L-5-hydroxytryptophan hydrate, and 6-hydroxy-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (carboline)] either separately or in mixtures. In choice and no-choice settling tests, aphid acceptance of barley plants was significantly reduced following treatment with root exudates, and the carboline when tested alone or in combination with the other compounds. In contrast, the other compounds without the carboline were less active in reducing aphid acceptance. In a probing bioassay, individual substances were either neutral or stimulatory to aphids, indicating that the reduced settling was probably not due to direct effects on aphids, but rather due to effects on the plant. This was confirmed in olfactometer assays, in which aphids were repelled by odors from barley plants following treatment with a mixture containing all four chemicals

Published in

Journal of Chemical Ecology
2003, Volume: 29, number: 2, pages: 261-274
Publisher: KLUWER ACADEMIC/PLENUM PUBL

SLU Authors

• Pettersson, Jan

  • Department of Entomology, Swedish University of Agricultural Sciences
    

• Ahmed, Elham

  • Department of Entomology, Swedish University of Agricultural Sciences
    

• Ninkovic, Velemir

  • Department of Entomology, Swedish University of Agricultural Sciences
    

• Glinwood, Robert

  • Department of Entomology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Agricultural Science


Publication identifier

DOI: https://doi.org/10.1023/A:1022687025416

Permanent link to this page (URI)

https://res.slu.se/id/publ/217