Quantitative assessments of the incidence and severity of Mycosphaerella leaf disease were made on nine provenances (encompassing the four subspecies) of Eucalyptusglobulus Labill. over three seasons in 1990 in a trial in Victoria, Australia. Defoliation was also assessed and tree height and diameter measured. Mycosphaerella leaf disease increased rapidly from winter to spring with disease incidence reaching 100% in most provenances by summer. There were highly significant differences in disease severity among provenances, with provenances from E. globulus ssp. globulus Kirkpatrick and E. globulus ssp. bicostata (Maid, et al.) Kirkpatrick being the most severely affected, while provenances from E. globulus ssp. maidenii (F. Muell.) Kirkpatrick and E. globulus ssp. pseudoglobulus Kirkpatrick were only slightly affected. There were also highly significant differences among provenances within E. globulus ssp. globulus and E. globulus ssp. pseudoglobulus. There was a high correlation between disease severity in summer and defoliation, suggesting that Mycosphaerella leaf disease was the main causal agent in leaf fall. There was also a high negative correlation between disease severity and growth rate. This study shows the potential benefits of selecting resistant provenances of E. globulus to maximise production from plantations in areas where Mycosphaerella leaf disease is a problem.

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Caliciopsis pleomorpha sp. nov. is described from a severe stem canker disease of cultivated Eucalyptus cladocalyx 'Nana' (dwarf sugar gum) in Australia. The fungus is a pleomorphic ascomycete (Coryneliales), with pycnidial (pleurophomalike) and hyphomycetous (phaeoacremonium-like) morphs, and differs in these respects and in ITS sequences from other Caliciopsis spp. The fungus was also found associated with cankers on other Eucalyptus species growing in native habitats, and was successfully inoculated under glasshouse conditions into a wide range of Eucalyptus species on which it caused cankers of varying severity.

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Neither metalaxyl (100 mL of a solution of 2.0 g a.i./L, applied as a root drench to 10-L pots) nor phosphonate (foliar spray at 1.0 g a.i./L, applied to runoff) controlled Phytophthora cinnamomi stem infection of Leucadendron laureolum x L. salignum hybrid when applied 10 days after inoculation. Both fungicides were most effective when applied prior to inoculation. Neither fungicide was able to kill P. cinnamomi within established infections. The fungus survived within the vascular tissues of treated plants. Infection was confined to cortical tissue by wound periderm when the rate of tissue invasion by P. cinnamomi was slowed by the fungicides. The results confirm observations made in protea growers' fields that with highly susceptible species, systemic fungicides can have poor curative properties and should be used as a prophylactic, in conjunction with other disease control methods.