Ceratocystis wilt on <I>Eucalyptus</I>: First record from South Africa

Abstract

Wilt and death of an E. grandis × E. urophylla variety was recently observed in the Zululand region of KwaZulu-Natal, South Africa. Symptoms on the dying trees included a streaking pattern of discolouration in the sapwood and cambium of stems and roots. A fungus resembling a Ceratocystis sp. was consistently found sporulating on diseased material and isolated from the symptomatic root and stem tissue. DNA sequence analyses of the
Ceratocystis isolates, including multiple gene regions, identified the isolates as C. eucalypticola. Multiple ITS types were identified among the isolates sequenced, similar to those found in other, closely related, Ceratocystis species. Artificial inoculations under field conditions confirmed the pathogenicity of the isolates. This is the first report of a Ceratocystis sp. causing a wilt disease of Eucalyptus in South Africa.

Keywords: canker, Ceratocystidaceae, emerging disease, root infection, vascular wilt