Resistance of Eucalyptus Spp. To Invasion by Phytophthora cinnamomi

Abstract

The resistance of 21 Eucalyptus spp. to Phytophthora cinnamomi Rands was assessed using wound inoculation methods. Aggressive lesions were observed in Eucalyptus marginata Uarrah) only. Lesion development was initially compared in E. marginata and E. calophylla (moderately resistant). Further comparisons were made of lesions in roots and stems of E. marginata, E. calophylla, E. patens and E. Wandoo growing in close proximity, in forest south-east of Perth. E. wandoo was the most resistant; the fungus failed to establish. As stems proved convenient for inoculation, summer stem inoculation trials were made to rate the resistance of 21 Eucalyptus spp. grown on a rehabilitated mine site. Lesions formed in the species of the Monocalyptus and Corymbia subgeneric groups but did not develop in species of the subgenus Symphyomyrtus. An alternative laboratory method of rating susceptibility of roots to invasion was also tested. Excised roots of three eucalypts, Banksia grandis and Xanthorrhoea preissii were inoculated and incubated at 25°C. Length of the root invaded was recorded; results were not well correlated with those from field studies.