Farm Forestry New Zealand
PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Aulographina Leaf Spot of Eucalyptus
Forest Pathology in New Zealand No. 1,
1. Aulographina Leaf Spot of Eucalyptus.
Compiled: 1983, minor update 1990
Revised 2009
Fungus: Aulographina eucalypti (Cooke & Massee) von Arx & E. Müller
Type of injury
Leaves become disfigured but tree growth is not usually affected. However, heavy infestations may cause premature leaf drop or reduce photosynthesis.
Fig. 1 - Aulographina eucalypti on Eucalyptus fastigata .
Diagnostic features
Brown, roughly circular (2-15 mm in diameter) spots with a raised, crusty centre, and a dark margin on both sides of leaves and petioles. Spots on one side of the leaf are only rarely visible on the other side.
Minute (up to 2 mm long), black flecks (the fruiting bodies of the fungus) scattered on the leaf spots.
Hosts
Eucalyptus botryoides, E. delegatensis, E. fastigata, E. ficifolia, E. fraxinoides, E. globulus subsp. globulus, E. globulus subsp. maidenii, E. nitens, E. pilularis, E. regnans, E. saligna.
Distribution
Aulographina eucalypti is found throughout New Zealand.
Disease development
Initially small, circular, shield-like fruiting bodies of the asexual state develop on the surface of the lesion. These are followed by black, elongated fruiting bodies of the sexual state which are often branched and open by splitting along their length. The spores which initiate new infections are wind-dispersed and are discharged during periods of high humidity. Infection on new hosts occurs primarily in the lower crown. Young, expanding leaves are not susceptible. Infection of the new season’s foliage does not become evident until late summer.
Economic importance
Trees badly affected by A. eucalypti may have over 90% of their leaf area covered with lesions. This level of infection has been seen in E. regnans and E. delegatensis in some locations in the central North Island. Aulographina eucalypti is one of the suite of fungi associated with the foliage disease known as Barron Rd Syndrome. Other hosts are less affected with infection primarily occurring in the lower crown.
This fungus has been reported as causing serious defoliation of E. nitens in Victoria, Australia.
Control
Not considered necessary.
Bibliography
Dick, M. 1982: Leaf-inhabiting fungi of eucalypts in New Zealand. New Zealand Journal of Forestry Science 12: 525-537.
Dick, M.; Gadgil, P.D. 1983: Eucalyptus leaf spots. New Zealand Forest Service, Forest Pathology in New Zealand No.1.
Gadgil, P.D. 2005: Fungi on trees and shrubs in New Zealand. Fungi of New Zealand Volume 4. Fungal Diversity Research Series 16: 1-437
Ridley, G.S., Dick, M. 2001: An introduction to the diseases of forest and amenity trees In New Zealand. Forest Research Bulletin 220, Rotorua, New Zealand
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