Coniothyrium stem canker of Eucalyptus in South Africa
The occurrence of a new disease of Eucalyptus grandis in South Africa had been reported in Reporting Service 516/03 (1991-10). Further details on this pest have now been presented at the 6th International Congress of Plant Pathology in Montreal. A previously undescribed Coniothyrium sp. is causing stem canker which is characterized by small, circular, necrotic lesions on the young green bark that ultimately result in considerable stem malformation. Atypical, large, irregular lesions can also develop on highly susceptible cultivars. Pathogenicity tests have shown the pathogenicity of the fungus as well as the varying susceptibility of Eucalyptus species, clones and hybrids. The authors concluded that Coniothyrium stem canker has become within three years one of the most serious and debilitating diseases of Eucalyptus in South Africa. They assume that the pathogen has evolved in the country and that its distribution is restricted to South Africa. If this is so, the authors conclude, Coniothyrium stem canker could pose a serious threat to both native and exotic Eucalyptus spp. elsewhere in the world.
Sources
Kemp, G.H.J.; Wingfield, M.J. (1993) Coniothyrium stem canker disease of Eucalyptus in South Africa.
Presentation at the 6th International Congress of Plant Pathology, Montreal, CA, 1993-07/08-27/06.