Semiochemicals related to the aphid Cinara pilicornis and its host, Picea abies: a method to assign nepetalactone diastereomers.
Volatiles released by seedlings of Norway spruce infested with the aphid Cinara pilicornis were analyzed using SPME-GC-MS. Among the stress-induced compounds released by the host plant, citronellol, cis-trans-nepetalactone and cis-trans-nepetalactol was found. These compounds originated from the aphids and they were assumed to be pheromone components for this aphid species. To determine the relative stereochemistry of the nepetalactone, a diagnostic method was developed. The method was based on multivariate analysis of tabulated relative intensities of mass fragments of the four nepetalactone diastereomers. In the practical method described, a few pairs of fragments in the mass spectra were compared and, in combination with the Kovat's index, were used to unambiguously identify the relative stereochemistry of the nepetalactone.
Pettersson
Marie
M
KTH, School of Chemical Science and Engineering, Department of Chemistry, Ecological Chemistry Group, SE-100 44 Stockholm, Sweden.
Unelius
C Rikard
CR
Valterová
Irena
I
Borg-Karlson
Anna-Karin
AK
D000818:Animals; D001042:Aphids / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D028222:Picea / Q000469:parasitology*; D013237:Stereoisomerism