| Disease incidence (%) | Response | Ranking |
| 0% | Highly resistant | 0 |
| 0% - 1% | Resistant | 1 |
| 1% - 5% | Moderately resistant | 3 |
| 6% - 25% | Moderately susceptible | 5 |
| 26% - 50% | Susceptible | 7 |
| 51% - 100% | Highly susceptible | 9 |