| Code | Definition | Number of Accessions |
| 1 | no symptoms | 1 |
| 2 | invasion of the stem past the site of inoculation but not to the first node | 10 |
| 3 | invasion of the stem to the first node | 73 |
| 4 | invasion of the internode slightly past the first node | 235 |
| 5 | invasion to the middle of the internode | 162 |
| 6 | invasion to the second node | 69 |
| 7 | invasion slightly past the second node | 41 |
| 8 | invasion to the middleof the second internode and beyond | 11 |
| 9 | total plant collapse | 1 |