Percentage of diseased American elms categorized by extent of crown involvment; Detroit, Michigan.
| Percentage of diseased crown | ||||
|---|---|---|---|---|
| Month | 1 to 20 | 21 to 50 | >50 | Total |
| Disease elms removed only in fall and winter | ||||
| June | 11 | 23 | 17 | 51 |
| August | 13 | 22 | 14 | 49 |
| Diseased elms removed within 20 days | ||||
| June | 31 | 7 | 8 | 46 |
| July | 17 | 11 | 9 | 37 |
| August | 12 | 3 | 2 | 17 |