Crown and bole ratings and corresponding levels of pitch canker severity. A tree’s overall pitch canker rating was obtained by adding the crown and bole ratings, for a possible rating of 0 to 6.
| Crown rating | Percentage of terminal branch ends killed by cankers | Bole rating | Number of bole cankers |
|---|---|---|---|
| 0 | 0% | 0 | 0 |
| 1 | l%–20% | 1 | 1 or 2 |
| 2 | 21%–79% | 2 | 3 or 4 |
| 3 | ≥ 80% | 3 | ≥ 5 |