DAMAGE TO SURFACE ROOTS OF EUCALYPTUS-MARGINATA TREES AT SITES INFESTED WITH PHYTOPHTHORA-CINNAMOMI

Large surface roots from naturally occurring Eucalyptus marginata Donn ex Smith trees at two sites, part of each site being infested by Phyt ophthora cinnamomi Rands, were excavated to determine whether the numb er and/or size of pathogenic lesions could account for known differenc es in growth rate. There were no differences in the number of insect g alleries, rots, number of phloem lesions or total lesion length per me tre root length within different areas of the same site infested or un infested by P. cinnamomi. Three P. cinnamomi and nine Cryphonectria cu bensis (Bruner) Hedges lesions were found on more than 300 m of root l ength. It was concluded that these lesions are unlikely to result in s ignificant differences in tree growth.