Table 2.
The mortality response of adult male bed bugs exposed to vapors of essential oil components and dichlorvos and their corresponding percent evaporation values for the 24 h bioassay period.
| Essential oil components | N | LC50a, mg/L (95% FLb) | Slope ± SE | χ² | Df | P-value | % Evaporationc |
|---|---|---|---|---|---|---|---|
| Thymol | 180 | 20.50 (17.70–23.18)a | 2.19 ± 0.29 | 0.60 | 3 | 0.89 | 90 ± 4.86 |
| Carvacrol | 180 | 46.3 (37.8–54.9)b | 1.37 ± 0.15 | 8.65 | 5 | 0.124 | 26.89 ± 4.23 |
| Linalool | 240 | 51.2 (41.3–70.0)b | 1.09 ± 0.19 | 6.33 | 3 | 0.097 | 86 ± 6.77 |
| (±)-Camphor | 210 | 133.3 (106.9–157)c | 1.93 ± 0.28 | 5.86 | 4 | 0.209 | 52.99 ± 23.95 |
| Menthone | 270 | 150.7 (132.3–169.3)cd | 2.03 ± 0.23 | 4.70 | 6 | 0.58 | 60.22 ± 20.33 |
| Eucalyptol | 180 | 191.1 (168.3–213.8)d | 2.77 ± 0.37 | 11.62 | 3 | 0.009 | 100 |
| (−)-Terpinen-4-ol | 210 | 388.3 (301.7–482.9)e | 0.96 ± 0.13 | 4.04 | 4 | 0.40 | 24.43 ± 16.55 |
| trans-Cinnamaldehdye | 240 | 389.0 (304.5–482.9)e | 0.90 ± 0.11 | 8.82 | 5 | 0.116 | 0.50 ± 0.50 |
| R (+)-Limonene | 270 | 454.0 (436.5–476.5)e | 6.69 ± 1.09 | 14.63 | 6 | 0.023 | 73.11 ± 9.25 |
| α-Pinene | 300 | 488.8 (470.8–503.6)e | 8.45 ± 1.10 | 23.71 | 7 | 0.001 | 87.36 ± 7.27 |
| (±)-Citronellal | 180 | 1474.6 (1047.7–2528.1)f | 0.63 ± 0.11 | 5.00 | 4 | 0.286 | 21.57 ± 12.03 |
| Geraniol† | 180 | ND | 1.29 ± 0.53 | ||||
| Citronellic acid† | 180 | ND | 4.48 ± 1.22 | ||||
| Eugenol† | 180 | ND | 5.16 ± 2.73 | ||||
| Methyl eugenol† | 180 | ND | 0.65 ± 0.17 | ||||
| Positive control | |||||||
| DDVP | 270 | 0.0432 (0.0397–0.0468)g | 2.76 ± 0.32 | 4.08 | 6 | 0.665 | 95.95 ± 4.04 |
aLC50 = median lethal concentration (expressed as amount of essential oil constituents or insecticides per liter air i.e. mg/L) necessary to kill 50% of individuals. b95% FL = 95% fiducial limits. Daggers (†) show essential oil components for which accurate LC50 values were not determinable (ND) because less than 30% mortality was observed at the highest concentration (2000 mg/L) that was testable. LC50 values with the same letters are not significantly different based on the relative median potency analysis (refer Table S3 for details). Mortality in control groups was 0%. cPercent evaporation values for the 24 h bioassay period. Acetone applied to control filter papers evaporated completely (100%) during the 30 sec to 5 min drying period described in the methods section.