Early infection of Fagus sylvatica by Heterobasidion annosum sensu stricto

Heterobasidion annosum sensu stricto is the most important damaging agent in Scots pine stands planted on the former agricultural lands in Poland. The routine action in pine stands which have lost stability because of H. annosum root rot is to change stand management, including species conversion. In many cases, the Fagus sylvatica is used for this purpose. This study was the first assessment of widespread infection by H. annosum in young F. sylvatica plantations. Disease symptoms included atrophy and yellowing of leaves, wilting and the presence of pathogen sporocarps around the root collars of young trees. Heterobasidion annosum s. s. was observed on both 4‐ and 17‐year‐old beech. Based on annual increments, the disease could be present for 3–4 years before tree death. A high incidence of H. annosum in pine stumps of previous stands (80–100%) and dry periods in recent years may be the main reasons for such common infection of F. sylvatica. This work also showed that mice and frost were not the main killing factors F. sylvatica in plantations.