Table 4.
Topical toxicity of fluralaner and permethrin on six strains of house flies at 48 h.
| Strain | Insecticide | n | LD50 (95% CI) (ng/fly) | Slope (SE) | χ2 (p-value) | RR |
|---|---|---|---|---|---|---|
| NIU | Permethrin | 240 | 17.0 (16.2–17.9) | 8.4 (1.0) | 0.015 (0.90) | – |
| Fluralaner | 300 | 17.6 (15.8–19.2) | 4.7 (0.6) | 0.72 (0.40) | – | |
| KS17 | Permethrin | 320 | > 5,000 | – | – | > 290* |
| Fluralaner | 300 | 180 (139–243) | 1.4 (0.2) | 0.27 (0.97) | 10* | |
| USDA-R | Permethrin | 400 | 420 (378–467) | 3.3 (0.3) | 2.8 (0.25) | 25* |
| Fluralaner | 500 | 46.3 (40.7–52.3) | 2.5 (0.2) | 2.4 (0.50) | 2.6* | |
| USDA-mixed | Permethrin | 600 | 3,080 (2,650–3,570) | 1.8 (0.1) | 1.68 (0.79) | 180* |
| Fluralaner | 600 | 115 (101–131) | 2.3 (0.2) | 0.21 (0.995) | 6.5* | |
| PA-mixed | Permethrin | 320 | 719 (540–960) | 1.2 (0.2) | 5.0 (0.08) | 42* |
| Fluralaner | 320 | 127 (112–144) | 3.1 (0.3) | 0.17 (0.92) | 7.2* | |
| KS8S3 | Permethrin | 320 | 44.3 (36.6–52.5) | 2.0 (0.2) | 1.9 (0.39) | 2.6* |
| Fluralaner | 320 | 52.2 (45.9–60.1) | 3.0 (0.3) | 4.4 (0.11) | 3.0* |
RR Resistance ratio = LD50 of resistant or field strain divided by LD50 of NIU susceptible strain.
*No overlap of the 95% CI of the LD50 with that of the susceptible NIU strain for the same pesticide; i.e., level of resistance-susceptibility differs from NIU. For the RR > 2,900, * is assumed given the extreme magnitude of the difference in LD50 and the variance seen for the other LD50 values.