Figure 1.
Structural formula of pheromone compounds and pheromone inhibitors included in the non-host volatile blends.
Figure 2.
Synthesis of racemic dehydro-conophthorin.
Table 1.
Compounds and release rates used in the three trials.
Figure 3.
Reducing the release of trans-conophthorin and comparing a GLV-blend with 1-hexanol alone, Trial 1.
Results from field experiment in Asa, South Sweden, May − June 2006. Bars show mean relative catch per replicate ±1 standard error based on n = 21 replicates (trap rotations). Numbers below stimuli acronyms are release rates (mg/day; Table 1). Acronyms: Ph (+) = Ips typographus pheromone blend (ca 57 mg/day); Vn = (–)-verbenone; GLV = (3Z)-hexen-1-ol, (2E)-hexen-1-ol, 1-hexanol (6 mg/day for a 1∶1∶1 mixture), C6 = 1-hexanol; tC = trans-conophthorin. Bars with same letters are not significantly different (ANOVA on arcsin√(relative catch), followed by Dunnet’s T3 multiple range post-hoc test, p<0.05).
Figure 4.
Comparison of trap catch reduction by trans-conophthorin versus technical grade trans-conophthorin, Trial 2.
Results from field trapping test in Germundslycke, May – June 2007. Bars show mean relative catch per replicate ±1 standard error based on n = 81 (n = 80 for Vn; n = 79 for C6 at 60 mg/day) replicates. Numbers below stimuli acronyms are release rates (mg/day; Table 1). Acronyms: Ph = pheromone (commercial lure from Chemtica); Vn = (–)-verbenone; C6 = 1-hexanol; tC = trans-conophthorin; T-tC = technical grade trans-conophthorin. Bars with same letters are not significantly different (ANOVA on arcsin√(relative catch) followed by Dunnet’s T3, p<0.05).
Figure 5.
Test of dehydro-conophthorin, Trial 3.
Results from field trapping test in Parismåla, May 2008. Bars show mean relative catch per replicate ±1 standard error based on n = 15 replicates. Numbers below stimuli acronyms are release rates (mg/day). Acronyms: Ph = pheromone (IT Ecolure Tubus, Fytofarm, Slovakia); Vn = (–)-verbenone; C6 = 1-hexanol; tC = trans-conophthorin; DHC = dehydro-conophthorin. Bars with same letters are not significantly different (ANOVA on arcsin√(relative catch) followed by Tukey’s HSD multiple range post-hoc test, p<0.05).
Figure 6.
A) Dose-response curves recorded from the trans-conophthorin (tC) ORN class [23], demonstrating the highest sensitivity to the pure tC, and somewhat lower sensitivity to the technical grade tC (T-tC). The lowest sensitivity was recorded to dehydro-conophthorin (DHC) (n = 10, i.e. 5 sensilla from each sex). B) The physiological effect of T-tC and DHC (expressed as Hedges’ g effect size) in relation to pure tC that served as positive control in the analysis. Negative effect sizes indicate weaker responses to T-tC and DHC than to pure tC, as also seen in A. Responses with CI:s below zero were regarded as significantly weaker (p<0.05) than the response to pure tC at the specified dose.