Table 1. Synergistic interactions between N. ceranae (Nc) and fipronil (F).
| Exposure | Mortality (%) | ||||
|---|---|---|---|---|---|
| day 0 | day 7 | Observed | Expected* | χ2** | Effect |
| Nc + F | - | 83.7 | 57.7 | 11.7 | Synergistic |
| Nc | F | 81.4 | 57.2 | 10.2 | Synergistic |
| F | Nc | 66.5 | 47.3 | 7.8 | Synergistic |
| - | Nc + F | 71.9 | 46.8 | 13.5 | Synergistic |
*Expected mortality (ME) on day 22 has been calculated as MNc + MF (1-MNc/100), with MNc and MF being the observed percent mortalities caused by N. ceranae and fipronil alone respectively.
**The calculated χ2 is much higher than the theoretical χ2 (i.e. χ2 = 6.635, df = 1, p = 0.01).