PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Cyttaria galls on silver beech
Cyttaria galls on silver beech
Forest Pathology in New Zealand No. 9
Based on P.D. Gadgil (1985)
Causal organisms
Cyttaria gunnii Berkeley, C. nigra Rawlings, C. pallida Rawlings
Fig. 1 - Fruiting bodies of Cyttaria gunnii , covering and obscuring the small gall on which they
are borne. The immature fruiting bodies are lighter in colour than the honeycombed, mature
fruiting bodies.
Type of injury
Development of perennial galls on branches and stems leading to malformation and occasionally
to death of branches.
Diagnostic features
The fungi produce galls on branches and stems of silver beech ( Nothofagus menziesii ); these
galls are perennial and produce crops of fruiting bodies each spring (September -November).
The distinguishing features of the three species are as follows:
Cyttaria gunnii (Fig. 1, 2)
• Branch galls roughly spherical, rarely more than twice the diameter of the host branch, and
usually occupying about two-thirds of its circumference.
• Stem galls usually in the form of encircling bands.
• Gall surface under the bark contorted and projected into sharp spines.
• Fawn to bright yellow fruiting bodies, pear-shaped, up to 2 cm in diameter.
Cyttaria nigra (Fig. 2)
• Galls roughly spherical, usually considerably more than twice the diameter of the host branch
or stem. On larger trees, galls 1 m or more in diameter are common.
• Gall surface under the bark has bluntly rounded projections and a few, very short spines.
• Slack or black and gold fruiting bodies, pear-shaped with black incrustations, up to 2 cm in
diameter.
Cyttaria pallida (Fig. 2)
• Branch and stern galls long and spindle-shaped, sometimes several feet long.
• Dirty white fruiting bodies, spherical, somewhat flattened, up to 1.5 cm in diameter.
Host
Nothofagus menziesii
Distribution
The fungi are present throughout New Zealand, wherever the host tree is found.
Disease development
Germinated spores invade the tissues of new shoots and produce chemical substances which
cause proliferation of the host tissue and lead to gall formation. With C. gunnii and C. nigra the
fungus travels only a short distance in the host, producing localised galls. With C. pallida ,
however, the fungus grows down the branch or stem and the gall increases steadily in length for
many years.
Fruiting bodies arise from the spines produced in the wood of the host by the action of the
fungus. These spines, consisting of fungal hyphae and woody tissue, project through the bark
nearly to the exterior. Spores are discharged in visible clouds from ripe fruiting bodies.
The galls are perennial and keep growing as long as the host branch or stem is alive.
Fig. 2 - Left: Fruiting bodies of Cyttaria nigra . Note the large size of the gall in relation to the
diameter of the branch. Centre: Fruiting bodies of Cyttaria pallida produced on long, spindle-
shaped galls. Right: Fruiting bodies of Cyttaria gunnii .
Economic importance
Cyttaria galls are most often found on heavily branched trees growing either on the borders of
clearings or in open stands. Girdling galls may lead to the death of upper parts of the branch or
stem. Galls of C. pallida cause twisting of the branches, which often break in high winds.
The effect of Cyttaria spp. on timber production in managed N. menziesii stands has not been
studied.
Control
No control measures are known.
Notes: Species of Cyttaria grow only on Nothofagus spp. and are also found in South America
(6 species) and Australia (2 species). In South America, the galls are used for making ornaments
and the fruiting bodies are eaten.
Bibliography
Gadgil, P.D. 1985: Cyttaria galls on silver beech. New Zealand Forest Service, Forest Pathology
in New Zealand No. 9.
Rawlings, G. B. 1956: Australasian Cyttariaceae . Transactions of the Royal Society of New
Zealand 84: 19-28.
Compiled: 1985: Revised 2010.
