IMPACT AND SYMPTOMS OF ARMILLARIA-LUTEOBUBALIULA IN REHABILITATION PLANTINGS OF EUCALYPTUS-SALIGNA IN FORESTS OF EUCALYPTUS-MARGINATA IN SOUTH-WESTERN AUSTRALIA

Armillaria luteobubalina was found in two of the nine surveyed plantin gs of Eucalyptus saligna near Dwellingup, established in the early 197 0s to rehabilitate cleared areas in forests of E. marginata that had b een degraded by infection by Phytophthora cinnamami. A. luteobubalina was present in 5 dead trees in one planting, and in 17 dead trees and 23 living trees with basal lesions at one end of a second planting. Wi thin the diseased area of the second planting dead and infected trees tended to occur near old stumps. Trees with basal stem lesions grew mo re slowly than trees without, but the differences were not statistical ly significant. In five trees of E. saligna excavated, a basal lesion occurred where the stem of one tree had grown against an old stump of E. marginata colonised by A. luteobubalina, and in a second tree, infe ction originated from contact between lateral roots and an old infecte d root of E. marginata. Susceptibility of E. saligna to infection decr eased with age as no tree have died during the period 1988-1993 and co nfined basal lesions had callused over. Adequate removal of inoculum i n stumps and roots would be important in minimising damage by A. luteo bubalina in plantings established on sites in south-western Australia that were formerly indigenous forest.