Table 1.
Toxicity of monoterpene volatiles against MPB from cohort 1.
| Cohort 1 | |||||
|---|---|---|---|---|---|
| Monoterpenes | N | LC50 [μl/L] (f.l.) | Hill Slope ± SE | χ2 (df) | Mean Weight [mg] ± SE |
| (−)-Limonene | 144 | 49 (34–71)a | −1.6 ± 0.3 | 5.4 (3) | 9.33 ± 0.22 |
| (+)-Limonene | 120 | 89 (66–120)b | −2.1 ± 0.6 | 8.5 (1) | 8.51 ± 0.19 |
| (+)−3-Carene | 120 | 117 (86–158)bc | −2.3 ± 0.6 | 8.8 (3) | 8.66 ± 0.19 |
| Myrcene | 119 | 163 (113–234)cd | −2.2 ± 0.6 | 4.0 (3) | 8.54 ± 0.21 |
| (+)-α-Pinene | 120 | 185 (151–227)cd | −4.1 ± 1.2 | 4.6 (3) | 8.63 ± 0.19 |
| (−)-β-Pinene | 120 | 221 (164–296)d | −3.3 ± 1.2 | 2.3 (3) | 8.94 ± 0.19 |
| (−)-α-Pinene | 120 | 277 (160–477)d | −1.4 ± 0.4 | 5.3 (3) | 9.07 ± 0.20 |
| Terpinolene | 120 | >500 | 8.74 ± 0.21 | ||
Dose-response models of the logit-transformed mortality data were used to determine the LC50 values, 95% fiducial limits (f.l.), and Hill slope for each monoterpene tested. LC50 values denoted with the same letter were not significantly different. Multiple comparisons between LC50 values were conducted via pairwise t-tests on the log (LC50) values of the Hill equation, using a pooled standard error, and correcting for experiment-wise error by the Benjamini–Hochberg procedure. The goodness-of-fit test χ2 (degree of freedom) was used to assess the fit of the dose-response model. Less than 50% of the beetles died at all doses of terpinolene. The mean weight of the beetles tested for each compound in cohort 2 was not significantly different and the mean weight of the beetles tested with a given monoterpene was the same at all doses (ANOVA, p-value = not significant). As sex was not a significant factor in mortality for all monoterpenes tested, the data for both sexes was combined.