Table 2. Toxicity of permethrin and pirimiphos methyl by topical application to adult Aedes aegypti and the synergistic effects of PBO.
Insecticide | Population or strain | na | Slope ± SE | LD50 (ng/♀) | 95% CL | SRb | RRc |
Permethrin | SMK | 354 | 7.0 ± 0.64 | 1.5 | 1.4–1.6 | 1.0 | |
SPS0 | 480 | 2.0 ± 0.14 | 52 | 37–74 | 35 | ||
SPS1 | 440 | 2.2 ± 0.18 | 106 | 92–123 | 71 | ||
SPS2 | 199 | 3.9 ± 0.41 | 212 | 157–278 | 141 | ||
SPS3 | 200 | 4.7 ± 0.51 | 318 | 212–443 | 212 | ||
SPS4 | 280 | 4.2 ± 0.37 | 509 | 461–562 | 339 | ||
SPS5 | 400 | 3.2 ± 0.26 | 685 | 610–769 | 457 | ||
SPS6 | 280 | 7.4 ± 0.75 | 757 | 684–838 | 505 | ||
SPS7 | 360 | 5.2 ± 0.50 | 1090 | 959–1240 | 727 | ||
SPS8 | 360 | 4.7 ± 0.46 | 1650 | 1440–1890 | 1100 | ||
SPS9 | 280 | 6.4 ± 0.65 | 1900 | 1690–2130 | 1270 | ||
SPS10 ( = SP) | 280 | 5.0 ± 0.59 | 2470 | 2160–2840 | 1650 | ||
F1(SP♀ × SMK♂) | 200 | 11.8 ± 1.5 | 14 | 13–15 | 9.3 | ||
F1(SMK♀ × SP♂) | 240 | 7.8 ± 0.84 | 12 | 11–14 | 8.0 | ||
BC1(SMK♀x F1(SP♂ × SMK♀)♂) | 320 | 5.8 ± 0.62 | 3.6 | 3.2–4.0 | 2.4 | ||
BC1(F1(SP♀ × SMK♂)♀ × SMK♂) | 320 | 5.9 ± 0.62 | 4.9 | 4.4–5.5 | 3.3 | ||
Permethrin +PBOd | SMK | 300 | 6.0 ± 0.55 | 0.89 | 0.83–0.95 | 1.7 | 1.0 |
SPS0 | 420 | 2.8 ± 0.22 | 9.8 | 7.3–13 | 5.3 | 11 | |
SPS10 ( = SP) | 360 | 5.8 ± 0.57 | 30 | 26–34 | 82 | 34 | |
SP♀ × SMK♂ | 200 | 9.7 ± 1.4 | 3.3 | 3.0–3.6 | 4.2 | 3.7 | |
SMK♀ × SP♂ | 240 | 10.5 ± 1.2 | 2.3 | 2.1–2.5 | 5.2 | 2.6 | |
Pirimiphos methyl | SMK | 360 | 10.5 ± 0.94 | 7.7 | 7.0–8.4 | 1.0 | |
SPS0 | 359 | 6.5 ± 0.56 | 20 | 19–21 | 2.6 | ||
SPS10 ( = SP) | 200 | 16.2 ± 2.2 | 38 | 35–41 | 4.9 |
n, number of females tested.
SR, synergistic ratio = LD50 (without PBO)/LD50 (with PBO).
RR, resistance ratio = LD50 (each population)/LD50 (SMK).
PBO (5 µg/mosquito) was administered 1 h prior to permethrin treatment.