Ink disease: possible confusion
If an observer is to determine whether a chestnut tree is affected by blight, it is essential to observe one or more of the symptoms that characterise the disease. Unfortunately, these are not specific and can be caused by various other biotic and abiotic causes:
Symptoms |
Elements for ink diagnosis |
Elements for other diagnoses |
Shoot wilting and/or mortality |
Generalized dieback Observation of root or collar necrosis. No rhizomorphs. |
Canker disease: sectorial mortality, subcortical mycelium, orange fruiting bodies. Nutritional deficiency, water stress: no necrosis Armillaria: root infections, subcortical rhizomorphs |
Defoliation |
Leaves reduced |
Cynips: galls and leaf deformation |
Black discharge |
Cortical necroses observed under the discharge after stripping. |
Galleries of wood-eating insects: no necrosis Frost: splitting of the wood |
Root necroses |
Infected or destroyed fine roots, infected taproot or large roots sometimes up to the collar. |
Armillaria: rhizomorphs |
Trunk necroses |
Trunk necroses are caused by root necroses |
Javart: lesions not related to the roots |