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Hundreds of mites sent to Tonga to tackle invasive plants

BUGS WITH BENEFITS: Mites form leaf galls, known as erinea, and stunt new growth and reduce the competitive ability of African tulip trees.Pictures supplied by Manaaki Whenua
CLUSTER: Each gall can contain hundreds of mites.
READY TO GO: Mites packaged and sealed by AsureQuality ready for the journey to Tonga.
BIOCONTROL: The package was delivered by national invasive species coordinator Viliami Hakaumotu, right, on arrival to representatives of Tonga’s Ministry of Agriculture Food, Forests & Fisheries.

Researchers at Manaaki Whenua Landcare Research (MWLR) successfully shipped a courier package containing a tree cutting infested with gall mites to Tonga

The shipment will ramp up weed-busting work in Tonga by introducing the gall mites to help reduce the spread and density of the invasive African tulip tree.

Manaaki Whenua Pacific Natural Enemies — Natural Solutions (NENS) coordinator Temo Talie said the shipment was an important milestone for Tonga.

“The gall mites are a specialist natural enemy of the African tulip tree and form leaf galls known as erinea, which stunt new growth and reduce the invasive plant’s competitive ability,” Mr Talie said.

The African tulip tree is considered one of the 100 worst alien invasive species in the world and one of the top 30 terrestrial invasive plants.

Introduced to many Pacific islands as an ornamental plant, the trees pose a huge threat to island biodiversity.

Native to Africa, the fast-growing evergreen tree infests rainforests, out-competes native vegetation and impacts agricultural production.

After the gall mites were brought to New Zealand from Ghana, via South Africa, in 2016, they were mass-reared in the MWLR containment facility in Auckland before being transferred to a containment facility in Lincoln to prepare the mites for the shipment to Tonga.

The mites had to be hand-transferred on to new plants to ensure the new population was free of any contaminants and pests, said entomology technician Arnaud Cartier, who looked after the mites in Lincoln.

The gall mites have been extensively tested to ensure no other plants are at risk and have been approved for release in Tonga.

“The gall mites will be reared by Ministry of Agriculture staff on Tongatapu, and then released in all parts of Tonga where they are needed,” Tonga’s national invasive species coordinator Viliami Hakaumotu said.

Work to control the African tulip tree was one of many projects being supported by the Global Environment Facility and New Zealand’s Ministry of Foreign Affairs to better manage invasive species in the Pacific.

Manaaki Whenua, the Secretariat of the Pacific Regional Environmental Programme and the New Zealand Department of Conservation have joined forces to support Pacific Island countries and territories to take stronger action against invasive species, and thereby build resilience to climate change.

  1. Konrad Englberger says:

    Hi, I have been working in Pohnpei, Micronesia for over 20 years in Plant Protection, Biosecurity and Invasive Species.
    In Pohnpei African Tulip is a major problem and is spreading very fast.
    Our Invasive Species Taskforce of Pohnpei (iSTOP) has a great interest in the mite for biocontrol. What can we do to get help?
    Kind regards,
    Konrad Englberger