Pathogens of the Araucariaceae: How Much Do We Know?

Purpose of Review The Araucariaceae is a family of ancient conifers containing iconic tree species from diverse parts of the world. Thirty-eight extant species are present in three genera. Extensive reduction of natural populations has occurred for many species of Araucariaceae, largely due to anthropogenic disturbances. This has occurred to the extent where most species are classified at some level of extinction risk. In recent decades, several diseases have emerged on trees in the family, which has highlighted a general lack of knowledge regarding the factors impacting the health of Araucariaceae. We addressed this by compiling all available literature regarding pathogens and diseases of the Araucariaceae. Insights are given into how globalization and climate change may have, and will potentially, play a role in the emergence of current and future disease threats. These threats are considered from both an ecological and economic perspective. Recent Findings A total of 227 disease reports were found for the family (58 for Agathis , 161 for Araucaria and eight for Wollemia ), of which 88% related to only eight tree species. Consequently, there was a considerable number of species in the Araucariaceae for which no disease reports were found. The most prevalent pathogens reported were species of Phytophthora , root rotting basidiomycetes such as Phellinus or Armillaria , and pathogens within the Botryosphaeriaceae. However, only 25% of the pathogens found have had their pathogenicity confirmed through tests, and only 22% have had their identity confirmed through DNA sequencing, making evident the limited amount of research carried out on this topic. Summary There is a general lack of baseline information on diseases for trees in the Araucariaceae. The effects that pathogens have had, and may have in the future, in this iconic family of trees are concerning as most of the species have been declared at some level of risk of preservation. Both globalization and climate change have indicated the potential effects they can have, and how unpredictable they can be. This lack of a solid baseline understanding may become an important constraint on attempts to preserve these species, and thus, it is evident that research efforts on these topics are much needed.