Mechanisms of intertree transmission of Ceratocystiswageneri in young Douglas-fir

Publisher Website
Google Scholar
Abstract
Root-feeding insects are known to vector black-stain root disease in Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). Intertree spread through root grafts and limited growth through soil is demonstrated as well. In potted seedling experiments, contact between roots of inoculated and healthy seedlings was either allowed or prevented. Transmission occurred in both treatments but was significantly more frequent (P = 0.01) when intertree root contact was allowed. In the root-contact treatment, 67% of the receptor seedlings died as a result of successful transmission. In the noncontact treatment, 35% of the receptor seedlings died. Evidence points to wounds on fine roots as principal infection courts. Root graft transmission of C. wageneri was verified through field excavation and microscopic examination of 23 root grafts from three widely separated sites.