Native Guava (Bolwarra)

Native Guava, or it's Indigenous name, Bolwarra, is a shrub or small tree which can be mainly by found in coastal, low elevation areas between the north of Sydney, New South Wales through to Maryborough in Queensland. This plant is a survivor from the first flowering plants to appear on the supercontinent Gondwana.

Bolwarra is the Aboriginal name and has been a food source for thousands of years. It grows naturally in eastern Australia and when the fruit ripens in Winter it can be eaten fresh or used in drinks or jams. It can also be dried and powdered and used as a spice.

The pale cream white flowers are heavily scented and appear in Summer followed by urn-shaped berries which ripen in Winter. This is a plant that is native to rainforests and needs to be protected from both frosts and hot drying winds.

Bolwarra was listed by the federal government as critically endangered in December 2020 due to the effect of Myrtle Rust (Austropuccinia psidii) infection which has severely impacted the entire species across its range and its high susceptibility to this

disease. It is currently listed as one the federal governments priority species.

Myrtle rust is one of the most significant native plant diseases to enter Australia. The disease, myrtle rust, arrived in Australia in 2010 and poses a major threat to the survival of dozens of Australian plant species. The disease is highly contagious which produces trillions of microscopic spores which are carried by the wind, quickly spreading to new areas.

Myrtle rust grows best in dark and damp conditions. The fungus penetrates the plant’s cells to draw nutrients from its host, damaging the plant. Myrtle rust is often characterised by the vibrant yellow dust-like appearance of its spores. However, plants can be infected with myrtle rust without showing this symptom.

Native Guava with sign of myrtle rust.

There are at least 15 rainforest tree species at risk of extinction in the wild due to myrtle rust infection.

There is no effective or practical chemical, biological or management control currently available.

In 2022, the Australian Government established the National Myrtle Rust Working Group. The group brings together experts from across Australia and New Zealand to drive a coordinated response to myrtle rust. Only one strain of myrtle rust exists within Australia, however, other strains are present overseas. These close relatives of myrtle rust could have devastating impacts on Australian plants if they were to enter Australia. This is why biosecurity measures are essential to ensure other strains of myrtle rust do not enter Australia in the future.