The International Camellia Society [ TOPICS ] [Pests & Diseases ] [ Camellias and Fungi ]

• Exobasidium camelliae -- leaf gaul -reasonably benign.
• Glomerella cingulata (Stone) Spaud -- Shoot and plant die-back.
• Armillaria species -- severe root-rot problems.
• Phytopthera and Pithium species -- severe root-rot problems.
• Ciborinia camelliae -- called Camellia flower blight.
• Botrytis species -- causes a similar flower blight.

Glomerella cingulata is a problem with some species including C. williamsii, C. japonica, C. sasanqua and C. saluenensis. Only some cultivars are prone to infection, C. williamsii 'Donation' being very difficult to grow in the Sydney climate. The summary of his research by Dr. A.L.Bertus in the I.C.S. Journal number 7, November, 1975 says all that needs to be said as to con- trol measures.

Armillaria species are, perhaps, the most difficult to control. It is not a problem of potted plants but is common in gardens, particularly those established in former woodland. By the time the infection has been identified there are many infected and dead infected roots and stumps in the ground. I have used Trichoderma species of anti-fungal fungi against the Armillaria lutobubulina in my garden which has probably protected uninfected plants but has done nothing for those already infected or prevented the fruiting of the Armillaria from the dead roots or the severely infected trees.

Phytopthera and Pithium species cause root-rot both in pots and in the ground. Potting in sterilised soils and using uninfected water with the soil being free draining could be one answer to the problem. Some Camellia sasanqua and Camellia hiemalis are resistant to these pathogens. Most of the camellias grown by Camellia Grove Nursery in Sydney are on C. hiemalis 'Kanjiro' stock, either by grafting on struck stock or as cutting grafts. Here are several treatments for infected soils or plants. 'Fongarid' made by Ciba-Geigy is effective as a soil drench, particularly for potted plants and an anti-fungus fungi 'Trichoderma species' available from J.H. Biotech of PO Box 7943. Ventura, California 93006. U.S.A. IS POSSIBLY MORE EFFECTIVE as it has a 6 monthly protection, at least, against the 8 to 14 days of the 'Fongarid'. A further treatment which has been successfully trialed is the use of phosphorus acid in the Jarra forests of Western Australia.It appears that the phosphite is taken up from the trees by the phytophtera in error for the phosphate and is then unable to metabolise it, building up high concentrations at the expense of the phosphate it needs. The attached article by Roger Armstrong will give further information.

Ciborinia camelliae is a flower blight fungus similar to the one affecting azaleas. When the infected flower falls to the ground, if the conditions are right, it forms a sclerotium which ,at flowering time fruits and releases the spores to infect the flowers. It is not present in Australia but has taken hold in New Zealand so I refer you to the article by T.M.Stewart from the NZ Camellia Bulletin Issue 118, July, '94. (Note: You will jump to a different path. To come back here, click the browser's back button).

Botrytis causes a similar flower blight to that caused by the Ciborinia. The difference in appearance is that the Botritis shows grey mould amongst the petals, whereas the Ciborinia will ususlly show a collar or a partial collar of mould at the base of an infected flower under the calyx. Usually, spraying with 'Triforine', 'Bayleton', or as suggested for Ciborinia could help stop the spread of the fungus. As with any sclerotia forming fungi, if the Trichoderma has been used it could inhibit these and break the cycle.

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