6533b7d8fe1ef96bd1269832

RESEARCH PRODUCT

Infection and spread of root rot caused byHeterobasidionspp. inPinus contortaplantations in Northern Europe: three case studies

subject

description

This study investigated the origins and spread patterns of Heterobasidion root disease in three Pinus contorta Dougl. ex Loudon plantations established on forest and agricultural land and subjected to three different management scenarios. Trees with decline symptoms and stumps remaining from the previous rotation were sampled for fungal isolations. Ten isolates of Heterobasidion parviporum Niemelä & Korhonen and 425 of Heterobasidion annosum (Fr.) Bref. were tested for clonality through somatic compatibility tests. The following conclusions were reached: (i) P. contorta is highly susceptible to H. annosum and H. parviporum and both pathogens cause dieback of P. contorta; (ii) H. annosum from previous-rotation P. sylvestris stumps can effectively transfer to P. contorta; (iii) the pathogens may form constantly expanding territorial clones; (iv) basidiospores of both pathogens colonise stumps of P. contorta (primary infections); (v) H. parviporum clones expanded more slowly than clones of H. annosum; (vi) clonal spread proceeded more quickly from stumps with established secondary infections than from stumps with primary infections; (vii) H. annosum can persist in pine stumps for at least 26 years; and (viii) stump treatment should be considered to control Heterobasidion primary infections.