Abstract
Mortality of Eucalyptus marginata seedlings following infection by Phytophthora cinnamomi was lower when planted with Acacia pulchella than when planted with Banksia grandis. The protective effects of native legumes other than A. pulchella against P. cinnamomi have not been determined. Field and glasshouse inoculation trials were set up to investigate the protective potential of five Western Australian native Acacia species for B. grandis. In the field only A. pulchella protected B. grandis against P. cinnamomi infection. Mortality of B. grandis planted with A. pulchella was as low as uninoculated B. grandis planted alone. Mortality of B. grandis planted with A. urophylla, A. extensa, A. latericola or A. drummondii was high and similar to inoculated B. grandis planted alone. In the glasshouse none of the Acacia species definitively protected B. grandis. Mean mortality due to infection by P. cinnamomi of B. grandis planted with A. pulchella or A. latericola was less than the control. However the remaining B. grandis seedlings died following infection by an unidentified fungus, hence protection could not be concluded.