Landscape Plants

Kauri dieback: This is a serious disease of the kauri trees of New Zealand which is caused by a soil borne fungal-like microorganism, Phytophthora agathidicida.  (agathidicida: Latin, agathid, for Agathis, the kauri genus, and -cide, derived from cadere to kill; hence a “kauri killer”).  It is not known when the microorganism arrived in New Zealand, but a high tree mortality rate and rapid speed of the disease since 2016 suggests a recent arrival.  Disease symptoms can include rot in roots and around the tree base, bleeding resin, yellowing of leaves, defoliation, and finally, death.  There is no established treatment for infected trees.  To reduce the spread of the microorganism some kauri forests have been closed to the public.  The disease is threatening kauri with extinction, and the loss could occur within three decade.  The indigenous people of New Zealand, the Māori, know this tree as Tāne Mahuta, lord of the forest, and it has a pivotal role in their creation story and its loss is considered a threat to Māori identity itself.  The Māori are leaders in the conservation and protection of the species, hopeful that such efforts will buy time for the development of a cure.