Farm Forestry New Zealand
PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Mycosphaerella on eucalypts
Scion is the leading provider of forest-related knowledge in New Zealand
Formerly known as the Forest Research Institute, Scion has been a leader in research relating to forest health for over 50 years. The Rotorua-based Crown Research Institute continues to provide science that will protect all forests from damage caused by insect pests, pathogens and weeds. The information presented below arises from these research activities.
From Forest Health News No. 79, October 1998.
Of the 27 species of Mycosphaerella known from leaves of Eucalyptus from around the world 17 have been described since 1994. Many of these species have been described from eucalypt plantations in South Africa and South America.
Growers of plantation eucalypts in New Zealand are familiar with 2 species, M. cryptica which causes leaf spots and defoliation of hosts such as E. delegatensis, E. fastigata, E. nitens and E. regnans (and also shoot and twig lesions resulting in dieback of some hosts) and M. nubilosa on the E. globulus subspecies and related species. A third species, M. swartii , which is most frequently found on E. regnans and E. fastigata, has been around for many years but does little damage and goes largely unnoticed. Abundant material of another species has been found this year on samples of E. saligna from forests in the eastern Bay of Plenty and from one forest in Northland. It was first collected from 1 to 2-year-old trees on leaves also affected with other foliar pathogens, and subsequently found on suppressed leaves of mature trees. The Forest Health Database has one unsubstantiated record from 1983 of a similar Mycosphaerella sp. on E. saligna from the eastern Bay of Plenty. If this is the same fungus then the lengthy period between collections suggests that until very recently it has existed at extremely low levels to go undetected. A further species of Mycosphaerella, on leaf spots of E. muelleriana, was found for the first time in New Zealand in a plantation near Kaikohe early in 1998. Although the site contains a wide variety of eucalypt species this fungus appears confined to E. muelleriana. To date this Mycosphaerella has not been recorded elsewhere. Neither of these two species exactly match any of the described species of Mycosphaerella on eucalypts. It is possible that some of the current species descriptions are too narrow at present and that, with expansion of the species concepts, these two fungi will find a slot among the 27 already described. Or, if not, the number of recognised eucalypt Mycosphaerella species will increase further. Taxonomic evaluations are in progress.
(Margaret Dick, Forest Research)
This information is intended for general interest only. It is not intended to be a substitute for specific specialist advice on any matter and should not be relied on for that purpose. Scion will not be liable for any direct, indirect, incidental, special, consequential or exemplary damages, loss of profits, or any other intangible losses that result from using the information provided on this site.
(Scion is the trading name of the New Zealand Forest Research Institute Limited.)
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