Beeches with parts of the crown showing yellow, later brown leaves, finally twigs and even branches may die off. Commonly irregular branching and growth anomalies appear. In detail: on the base of twigs with yellow leaves at first flat, dark brown to blackish discolored bark areas, later on cracking open;as a result of callusing the cankers swell and the part of the twig becomes deformed; finally the wood is exposed, surrounded by callus. In the cankers, tiny red, ball-shaped fruiting bodies appear in small groups.
Affected tree species
Occasionally important pathogen in crowns of beech; the fungus enters the tissues through wounds (mostly hail), sometimes also following attacks by bark beetles. More common in regions with drought stress than on (mountainous) sites with sufficient water supply. Old beeches infested by this canker disease are an important source of infection for beeches in the understory. Young beeches often die off, in old trees the timber quality can be devaluated.
Curative measures In old stands with >25% of infected trees, heavily cankered individuals should be removed to avoid the infestation of beeches in the understory or in the vicinity.
Neonectria ditissima: old beech showing yellowing of leaves according to numerous twig-cankers
Neonectria ditissima: old beech with yellow and brown twigs
Neonectria ditissima: beech twig with numerous cankers in different stages of development (marked in red)
Neonectria ditissima: initial stage of a canker: dark bark surface
Neonectria ditissima: several twig cankers, some with frutiting bodies, deformations
Neonectria ditissima: twig canker with fruiting bodies