Damage to Surface Roots of Eucalyptus marginata Trees at Sites Infested With Phytophthora cinnamomi

Abstract

Large surface roots from naturally occurring Eucalyptus marginata Donn ex Smith trees at two sites, part of each site being infested by Phytophthora cinnamomi Rands, were excavated to determine whether the number and/or size of pathogenic lesions could account for known differences in growth rate. There were no differences in the number of insect galleries, rots, number of phloem lesions or total lesion length per metre root length within different areas of the same site infested or uninfested by P. cinnamomi. Three P. cinnamomi and nine Cryphonectria cubensis (Bruner) Hedges lesions were found on more than 300 m of root length. It was concluded that these lesions are unlikely to result in significant differences in tree growth.