Intraspecific variation to anthracnose for four Fraxinus species. Cultivars/subspecies are listed in ascending order (increasing susceptibility) based on 3-year average disease severity ratings (DSR). Each tree was assigned a DSR by two individuals where 1 = healthy, no symptoms; 2 = < 25% of canopy exhibited necrotic blotching of leaves; 3 = 25%-50% of canopy with symptoms; 4 = 50%-75% of canopy with symptoms, and 5 = > 75% of canopy with symptoms. Means followed by different lowercase letters indicate a significant difference (p < 0.05) within a given year.
| Species | Cultivar/subspecies | # trees | Average DSR | Overall average DSR | ||
|---|---|---|---|---|---|---|
| 1997 | 1998 | 1999 | ||||
| F. americana | Autumn Applause | 5 | 1.0 ab | 1.0 a | 1.0 ab | 1.0 |
| subserrata | 2 | na | 1.0 a | 1.0 ab | 1.0 | |
| Champaign County | 3 | 1.0 ab | 1.7 a | 1.0 ab | 1.2 | |
| idiocarpa | 2 | 1.0 ab | 1.0 a | 2.0 a | 1.3 | |
| juglandifolia | 1 | 1.0 ab | 1.0 a | 2.0 a | 1.3 | |
| Autumn Purple | 12 | 1.6 a | 1.5 a | 1.3 ab | 1.5 | |
| species | 5 | 1.8 a | 1.0 a | 1.8 a | 1.5 | |
| F. angustifolia | species | 5 | 1.5 a | 2.2 ab | 2.0 b | 1.9 |
| Monophylla | 2 | na | 2.5 ab | 1.5 b | 2.0 | |
| australis | 5 | 1.4 a | 2.8 ab | 4.4 a | 2.9 | |
| pannonica | 2 | 1.5 a | 3.5 a | 5.0 a | 3.3 | |
| F. excelsior | Aurea | 1 | na | 1.0 c | 1.0 b | 1.0 |
| Diversifolia | 5 | 1.0 b | 1.2 c | 1.8 b | 1.0 | |
| Hessei | 7 | 1.6 b | 1.6 c | 1.3 b | 1.5 | |
| Kimberly | 2 | 1.5 b | 2.5 bc | 1.5 b | 1.8 | |
| Westhof ‘s Glorie | 3 | na | 2.3 bc | 2.3 b | 2.3 | |
| Nana | 4 | na | 3.3 ab | 2.5 b | 2.9 | |
| Pendula | 1 | 4.0 a | 5.0 a | 5.0 a | 4.7 | |
| F. pennsylvanica | Ovata | 1 | 1.0 d | 1.0 b | 2.0 b | 1.3 |
| Boscii | 1 | 2.0 cd | 1.0 b | 2.0 b | 1.7 | |
| species | 17 | 2.2 cd | 1.9 b | 2.9 ab | 2.3 | |
| Honeyshade | 4 | 3.5 b | 2.0 b | 2.5 ab | 2.7 | |
| Newport | 1 | 3.0b cd | 1.0 b | 4.0 a | 2.7 | |
| subintegerrima | 29 | 3.4 bc | 2.4 b | 3.1 ab | 3.0 | |
| Summit | 8 | 5.0 a | 1.4 b | 2.6 ab | 3.0 | |
| austinii | 2 | na | 2.5 b | 4.0 a | 3.3 | |
| Niobrara | 5 | 3.8 b | 5.0 a | 4.4 a | 4.4 | |