Lasiodiplodia species associated with dying Euphorbia ingens in South Africa

  • JA van der Linde
  • DL Six
  • MJ Wingfield
  • J Roux

Abstract

Various species of Euphorbia occur in South Africa, including herbaceous, succulent and woody types. The largest of the succulent Euphorbia spp. in South Africa is Euphorbia ingens. These trees have been dying at an alarming rate in the Limpopo province during the course of the last 15 years. Investigations into the possible causes of the death have included the possible role of fungal pathogens. Amongst the fungi isolated from diseased trees were species in the Botryosphaeriaceae. The aim of this study was to identify these fungi using morphology and DNA sequence data of two gene regions (TEF 1-α and ITS). Results showed that Lasiodiplodia theobromae and L. mahajangana were present, representing the first report of Lasiodiplodia species on a succulent Euphorbia species. Pathogenicity studies showed that these Lasiodiplodia species can cause infections on healthy E. ingens trees, implicating them as contributors to the decline of E. ingens.

Keywords: Botryosphaeriaceae, candelabra trees, climate change, insect infestations, tree diseases

Southern Forests 2011, 73(3&4): 165–173

Author Biographies

JA van der Linde
Department of Microbiology and Plant Pathology, DST/NRF Centre of Excellence in Tree Health Biotechnology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa
DL Six
College of Forestry and Conservation, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT 59812, USA
MJ Wingfield
Department of Microbiology and Plant Pathology, DST/NRF Centre of Excellence in Tree Health Biotechnology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa
J Roux
Department of Microbiology and Plant Pathology, DST/NRF Centre of Excellence in Tree Health Biotechnology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa
Section
Articles

Journal Identifiers


eISSN: 2070-2639
print ISSN: 2070-2620