![]() While all reasonable measures have been taken to ensure accuracy, MPI gives no warranty in relation to the accuracy, completeness, reliability or fitness for purpose of the map and accepts no liability whatsoever in relation to any loss, damage or other costs relating to any person's use of the map. The distribution map (Crown copyright) was created by Biosecurity New Zealand (Ministry for Primary Industries MPI) on 14 August 2019 based on data obtained from various sources available at that time. Red dots indicate where the presence of the P. agathidicida pathogen has been confirmed within the native range of kauri in the northern part of New Zealand. ![]() 1) and kauri are now identified as a threatened species (De Lange et al., 2018).ĭistribution of Phytophthora agathidicida across the natural range of kauri. Surveillance has revealed the widespread nature of the epidemic (Fig. The pathogen was subsequently confirmed in many locations within the natural range of kauri (Waipara et al., 2013). Kauri dieback was first reported in 1972 on Aotea Great Barrier Island in NZ (Gadgil, 1974), but was not recognized on the NZ mainland until 2006 (Beever et al., 2009). The survival of remnant kauri is now threatened by kauri dieback: a lethal root rot disease caused by the oomycete pathogen Phytophthora agathidicida (Weir et al., 2015), for which there is no known cure. In addition to this, about 60 000 ha of kauri forest that regenerated after the main period of forest exploitation also exists (Halkett, 1983) and much of the existing kauri forest is now protected (Steward & Beveridge, 2010). Before European settlement, kauri forest covered >1 million ha, but after more than 200 years of destruction by logging and burning, <1% of the original old-growth forest remains (Steward & Beveridge, 2010). Kauri are endemic to New Zealand (NZ), where they have immense cultural significance (Black et al., 2018) and are highly revered. Kauri is also one of the largest and longest-living tree species, with trunk diameters up to 4.4 m and an average lifespan of 600 years, although the oldest trees reported are well in excess of 1500 years in age (Ahmed & Ogden, 1987 Steward & Beveridge, 2010). Kauri, or Agathis australis, is one of the earliest diverging lineages of Agathis, a genus of about 17 extant gymnosperm conifer species within the Araucariaceae (Wilf et al., 2014). Kauri – an Ancient Tree Species Under Threat Key aspects of indigenous Māori knowledge, which include rich ecological and historical knowledge of kauri forests and a holistic approach to forest health, are highlighted. This review discusses current and emerging tools and strategies for surveillance, diagnostics and management, including a consideration of genomic resources, and the role these play in understanding the pathogen and how it causes this deadly disease. ![]() However, there is comparatively little known about many aspects of the biology of P. agathidicida, such as its host range and disease latency, or about the impact on the disease of abiotic and biotic factors such as soil health and co-occurring Phytophthora species. ![]() The life cycle of P. agathidicida is similar to those of other soilborne Phytophthora pathogens, with roles for vegetative hyphae, zoospores and oospores in the disease. This review brings together existing scientific knowledge about the pathogen and the devastating disease it causes, as well as highlighting important knowledge gaps and potential approaches for disease management. This disease has profound effects on both forest ecosystems and human society, particularly indigenous Māori, for whom kauri is a taonga or treasure of immense significance. The noted incidence of kauri dieback has increased in the past decade, and even trees >1000 years old are not immune. Kauri ( Agathis australis), which is one of the world's largest and longest-living conifer species, is under threat from a root and collar dieback disease caused by the oomycete pathogen Phytophthora agathidicida.
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