A History of Five Forest Diseases in South Africa

ABSTRACT

An historical sketch of several forest diseases in South Africa was compiled after a search of accessions at the National Collection of Fungi, correspondence housed at the Forestry Branch's archives, and other published and unpublished reports. Diplodia dieback was first found in 1909 in the eastern Cape; had been reported from all forest regions by 1938; caused Pinus radiata to be abandoned as a commercial species in the summer rainfall region during the 1920s; became an important problem with Pinus patula between 1930 and 1941, before which time this host was considered highly resistant. Armillaria root rot has been found primarily in the Northern and Eastern Transvaal and in Zululand; caused growers to temporarily consider abandoning afforestation in the Northern Transvaal during the early 1930s; has been most severe in first rotation stands on sites where certain indigenous tree species (particularly, Parinari curatellifolia) previously grew; has been caused by an as yet undetermined species of Armillaria. Mycosphaerella leaf disease of Eucalyptus spp. is one possible reason why Eucalyptus globulus and Eucalyptus maidenii were abandoned as commercial forest species in South Africa. Purple root rot and Pseudophaeolus root and collar disease were considered among the most important forest diseases in the early 1930s and 1950s, respectively.