Mycosphaerella diseases of juvenile foliage in a eucalypt species and provenance trial in Victoria, Australia.
The incidence of mycosphaerella leaf diseases and disease severity caused by 7 species of Mycosphaerella were assessed on the juvenile foliage of 14 species and 44 provenances of Eucalyptus in a 2-3 yr old trial in Australia. Significant variation was observed between the 14 host species, with E. cypellocarpa and E. nitens recording the highest disease incidence and E. elata and E. oreades having no assessable disease. The other 10 species included in the trial were E. botryoides, E. brookerana, E. fraxinoides, E. globulus, E. grandis, E. quadrangulata, E. saligna, E. sieberi, E. smithii and E. viminalis. While wide variation was observed between provenances within species, variation was significant only between provenances of E. nitens. Seven species of Mycosphaerella were recorded on diseased leaves collected from the trial. M. cryptica and M. nubilosa were the most damaging, with M. cryptica being the most common and having the widest host range; the other 5 species studied were M. grandis, M. gregaria, M. marksii, M. parva and M. swartii.