Percentage of ash yellows positive and negative trees with main stem or small branch dieback exhibiting individual decline symptoms.
| Symptoms | Ash yellows positive (% of trees) | Ash yellows negative (% of trees) | |||
|---|---|---|---|---|---|
| Main stem dieback (n = 4) | Small branch dieback (n = 7) | Main stem dieback (n = 32) | Small stem dieback (n = 102) | p* | |
| Sparse foliage | 100 | 43 | 97 | 70 | 0.46 |
| Clustered foliage | 100 | 0 | 72 | 37 | 0.75 |
| Loss of apical dominance | 100 | 57 | 22 | 10 | 0.42 |
| Basal sprouts | 50 | 0 | 53 | 22 | 0.73 |
| Epicormic sprouts | 100 | 43 | 16 | 4 | 0.01 |
| Witches’ brooms | 50 | 14 | 3 | 0 | 0.001 |
| Chlorotic foliage | 100 | 86 | 94 | 83 | 0.35 |
| Frost cracks | 0 | 0 | 3 | 2 | 0.78 |
↵*P = probability that the difference between the incidence of the symptom in ash yellows positive and negative trees is due to chance based on Chi-square analysis.