Kirramyces leaf diseases

Pale green leaf spots of Kirramyces infection on eucalypt leaves eventually turn yellow
© Queensland Government

Some leaf spots enlarge and eventually may cover the leaf
© Queensland Government

Kirramyces leaf blight can distort and buckle leaves
© Queensland Government
Kirramyces leaf diseases are a group of fungal leaf pathogens that infect mature and immature foliage in some eucalypts. They can cause severe defoliation in young trees and may become a significant problem in some hardwood plantations.
Four species of Teratosphaeria are known, some of these were previously referred to as Kirramyces species. They have different hosts, disease symptoms and known distribution.
Scientific name
Description
Teratosphaeria epicoccoides
- Initially, small purple angular leaf spots are obvious on upper leaf surfaces. These expand and coalesce, eventually covering the entire leaf surface.
- Lesions on the lower surface turn yellow to yellow-brown, forming angular blotches delimited by leaf veins.
- Brown to black spores may cover the underside of the leaf, giving a 'charcoal' appearance.
T. viscidus
- Circular or irregular necrotic (disease) spots appear on both leaf surfaces, with red borders on the upper surface.
- Severe shape distortion in young leaves.
- Conidia (spore masses) appear as crusty black masses.
- Infection begins in the lower canopy and spreads to the top, in some cases resulting in more than 90% defoliation.
T. psuedoeucalypti
- Necrotic (diseased) leaf spots (2–15mm diameter) appear on both leaf surfaces.
- Spots are single or joined, light to medium brown with red-purple margins.
- Crusty black masses are formed by conidia (spore masses) accumulating on lesions.
T. corymbiae
- Leaf spots are yellow-brown to tan and occur on both leaf surfaces.
- Usually affects fully expanded foliage on trees older than 2 years.
Distribution
Teratosphaeria epicoccoides
- Widespread throughout the tropics and subtropics.
T. viscidus
- Only identified from Mareeba in North Queensland
- Possibly more widespread in tropical Australia.
T. psuedoeucalypti
- Current distribution unknown but may prefer subtropical and tropical climates.
T. corymbiae
- Widespread in subtropical areas of Queensland and New South Wales.
Hosts
Teratosphaeria epicoccoides
- Eucalyptus grandis
- E. grandis hybrids
- E. pellita.
T. viscidus
- Eucalyptus grandis (damage was limited to lower foliage in the Copperload provenance)
- E. grandis x E. camaldulensis.
T. psuedoeucalypti
- Eucalyptus grandis hybrids
- Full host range unknown but observations suggest that Corymbia species are not susceptible.
T. corymbiae
- Corymbia species.
Damage
Teratosphaeria epicoccoides
- Affects older leaves in the lower canopy but sometimes throughout the crown.
- Infects older leaves causing premature senescence (deterioration with age) and leaf-loss spreads upwards from the lower canopy.
- Common in warmer and wetter months, and seasonal.
- Severe infection can result in complete defoliation.
T. viscidus
- Severe impact has been seen in Eucalyptus grandis x E. camaldulensis hybrids originating from South America where infection in new shoots and young foliage resulted in 75% defoliation.
T. psuedoeucalypti
- Severe defoliation (>75%) has occurred in central and south-eastern Queensland.
- Repeat infections have made some areas no longer viable for commercial plantations of susceptible species.
- Greatest impact on Eucalyptus grandis hybrids.
T. corymbiae
- Rarely severe enough to cause defoliation.
Monitoring and action
Teratosphaeria epicoccoides
- No specific chemicals have been registered for this pathogen.
T. viscidus
- No management required, as Eucalyptus grandis hybrids are not planted commercially in Far North Queensland.
- Relatively low disease in Australian E. grandis (Copperload) suggest some resistance.
- Tree germplasm developed overseas in the absence of Australian pests and diseases is potentially more susceptible.
T. psuedoeucalypti
- Avoid planting E. grandis hybrids, particularly germplasm developed overseas.
T. corymbiae
- None required.
Resources and research
- Carnegie, A, Lawson, SA, Smith, T, Pegg, GS, Stone, C, and McDonald, J 2008, Healthy hardwoods: a field guide to pests, diseases and nutritional disorders in subtropical hardwoods, Forest and Wood Products Australia, Victoria.
- Pests and diseases image library (PaDIL)
- Australian Pesticides and Veterinary Medicines Authority (APVMA)
- Last reviewed: 12 Dec 2018
- Last updated: 12 Dec 2018