Abstract

In large parts of Europe, insecticide-free measures for protecting conifer plants are desired to suppress damage by the pine weevil Hylobius abietis (L.). Treatment with methyl jasmonate (MeJA), a chemical elicitor already used in crop production, may enhance expression of chemical defenses in seedlings in conifer regenerations. However, in a previous experiment, MeJA treatment resulted in substantially better field protection for Scots pine (Pinus sylvestris L.) than for Norway spruce (Picea abies (L.) Karst.). Hypothesizing that the variations may be at least due partly to volatiles released by MeJA-treated seedlings and their effects on pine weevil orientation, we examined tissue extracts of seedlings (from the same batches as previously used) by two-dimensional GC-MS. We found that the MeJA treatment increased contents of the monoterpene (-)-beta-pinene in phloem (the weevil's main target tissue) of both tree species, however, the (-)-beta-pinene/(-)-alpha-pinene ratio increased more in the phloem of P. sylvestris. We also tested the attractiveness of individual monoterpenes found in conifer tissues (needles and phloem) for pine weevils using an arena with traps baited with single-substance dispensers and pine twigs. Trap catches were reduced when the pine material was combined with a dispenser releasing (-)-beta-pinene, (+)-3-carene, (-)-bornyl acetate or 1,8-cineole. However, (-)-alpha-pinene did not have this effect. Thus, the greater field protection of MeJA-treated P. sylvestris seedlings may be due to the selective induction of increases in contents of the deterrent (-)-beta-pinene, in contrast to strong increases in both non-deterrent (-)-alpha-pinene and the deterrent (-)-beta-pinene in P. abies seedlings.

Keywords

Hylobius abietis; Pinus sylvestris; Picea abies; Monoterpenes; Methyl jasmonate; Enantiomers

Published in

Journal of Chemical Ecology
2016, Volume: 42, number: 12, pages: 1237-1246
Publisher: SPRINGER

SLU Authors

• Nordlander, Göran

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Björklund, Niklas

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Nordenhem, Henrik

  • Department of Ecology, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network


UKÄ Subject classification

Forest Science
Biochemistry and Molecular Biology
Ecology


Publication identifier

DOI: https://doi.org/10.1007/s10886-016-0790-z

Permanent link to this page (URI)

https://res.slu.se/id/publ/79180