Weed-busting African Tulip Beetles Arrive In Tonga

A cohort of 210 African tulip beetles (Paradibolia coerulea) has arrived in Tonga ready to start the important job of controlling the invasive African Tulip Tree (Spathodea campanulata).

As the technical lead for the Pacific Regional Invasive Species Management Support Service’s (PRISMSS) Natural Enemies - Natural Solutions (NENS) Programme a team from Manaaki Whenua – Landcare Research delivered beetles to their colleagues at Tonga’s Ministry of Agriculture, Food, and Forests (MAFF). The beetles will be mass reared at the Vaini Research station in Tongatapu before being released at several sites around Vava’u.

Programme lead for the PRISMSS NENS team that is spearheading natural enemy weed control work across the Pacific, Lynley Hayes says the beetles have been extensively tested to ensure no other plants are at risk from it and have already been deployed in the Cook Islands.

“These are leaf-mining beetles. Adult beetles eat holes in the African tulip leaves and their larva mine through them,” says Lynley. “The beetles have been approved for release in Tonga and will ramp up efforts to help reduce the spread and density of the African tulip tree.”

Tonga’s National invasive species co-ordinator Viliami Hakaumotu says the beetles will be released on Vava’u where another specialist enemy of the African tulip tree, a gall-forming mite (Colomerusspathodeae) was released in December 2023. “The mites and beetles will work together in areas where the weed is too widespread for management through conventional methods,” he says.

The African tulip tree invades indigenous forests and arable land causing reductions in natural biodiversity and agricultural productivity. Originally from West Africa, it was introduced into the Pacific as an ornamental plant but has now naturalised and become problematic. Both the beetle and mite were found in Ghana and developed with the assistance of Rhodes University in South Africa.

The Secretariat of the Pacific Regional Environment Programme (SPREP) Invasive Species Adviser, Mr. David Moverley commented, “African tulip is a common problem across the Pacific and it is great to see these two helpful natural enemies being relocated to the Kingdom of Tonga.”

“Whilst the impacts of African tulip to productive land are more immediately obvious, the impacts on native biodiversity and ecosystems are often out of sight as they grow and spread in shady areas under the forest canopy. Many catchments in the Pacific are impacted by this species by displacing native plants and reducing catchment stability and resilience.”

This project is part of the Restoring Island Resilience Programme administered by SPREP, and funded by New Zealand’s Ministry of Foreign Affairs (MFAT) and the Global Environment Facility, to better manage invasive species in the Pacific and enhance the resilience of Pacific communities to climate change.

PRISMSS is a coordinating mechanism designed to facilitate the scaling up of invasive species management in the Pacific. PRISMSS brings together experts to provide support within the Pacific region with a focus on protection of indigenous biodiversity and ecosystem function and provides a comprehensive suite of support services in a cohesive, effective, efficient, and accessible manner to Pacific Island countries and territories.

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