Canadian Forest Service Publications
Sex pheromone chemistry and field trapping studies of the elm spanworm Ennomos subsignaria (Hubner) (Lepidoptera: Geometridae) 2010. Ryall, K.L.; Silk, P.J.; Wu, J.; Mayo, P; Lemay, M.A.; MaGee, D. Naturwissenschaften 97: 717-724.
Issued by: Atlantic Forestry Centre
Catalog ID: 31843
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The elm spanworm, Ennomos subsignaria (Hubner), occurs throughout Canada and the eastern United States and can be a destructive forest pest on a wide range of deciduous trees. Gas chromatography/mass spectrometry (GC/MS) and coupled gas chromatographic-electroantennographic detection (GC/EAD) analysis of pheromone gland extracts, in combination with chemical synthesis and field trapping studies have identified (2S, 3R)-2-((Z)-oct-2’-enyl)-3-nonyl oxirane (hereafter Z6-9S, 10R-epoxy-19:H) as the female-produced sex pheromone. Significantly more male moths were captured between 1-100 ug loadings of this compound on red rubber septa in sticky traps compared with blank (unbaited) traps; catches then declined at higher dosages (500-1000 ug). The other isomeric enantiomer, (2R, 3S)-2-[(Z)-oct-2’-enyl]-3-nonyl oxirane (Z6-9R, 10S-epoxy-19:H), at a 10-ug dosage did not elicit trap capture. The likely precursor to the active epoxide, (Z, Z)-6, 9-nonadecadiene ((Z, Z)-6, 9-19:H), identified in virgin female sex pheromone glands, did not elicit trap capture either, and inhibited trap capture when combined with the active epoxide. Racemic 2-((Z)-oct-2’-enyl)-3-noyl oxirane showed no significant difference in trap capture compared with Z6-9S, 10R-epoxy-19:H, indicating that the opposite enantiomer was not antagonistic. The addition of the EAD-active diene epoxide enantiomers (2S, 3R)-2-[(Z, Z)-octa-2’, 5’-dienyl]-3-nonyl oxirane of (2R, 3S)-2-[(Z, Z)-octa-2’, 5’-dienyl]-3-nonyl oxirane in admixture with Z6-9S, 10R-eopxy-19:H (at 10% of the latter) did not enhance or decrease trap cature compared with Z6-9S, 10R-epoxy-19:H oxirane alone, so they are not likely pheromone components. This pheromone, impregnated in rubber septa at less than 100-ug dosage, can now be used as a trap bait to develop detection and monitoring strategies for this insect.