Gladiolus aureus is a geophyte species endemic to the South African Cape Peninsula. Pressures including land-use change and invasion by alien plants have caused severe population declines, leading to its classification as Critically Endangered (CR). Kirstenbosch National Botanical Garden (NBG) maintains the largest ex situ collection of this species. During plant health surveys conducted as part of a sentinel plant research pr...

The globally important plant pathogen Phytophthora cinnamomi was first reported in South Africa in 1931, where it caused substantial damage to avocado orchards. Surprisingly, 40 years passed before the pathogen was recognised as a significant threat to South Africa’s natural ecosystems. This first became evident when P. cinnamomi caused a “quick decline” of the iconic silver trees ( Leucadendron argenteum ) in the Cape Florist...

The soilborne fungus Dematophora (= Rosellinia ) necatrix and causal agent of white root rot, has a wide host range that includes many tree species of economic importance. The pathogen has a worldwide distribution, including reports from commercial orchards in South Africa since the 1970s. During tree health surveys conducted as part of a sentinel plant project, we detected the pathogen on two symptomatic individuals from the...

Purpose of Review Human-caused global change is fundamentally altering natural forest ecosystems. More trees are exhibiting a wide range of symptoms indicative of poor vigour, particularly stressed species at the edge of their native ranges and stands growing on marginal sites. This review will focus on complex tree diseases (declines) caused by native pathogens and the key environmental drivers that contribute to this phenome...