Photo Credit: Manaaki Whenua Landcare Research
The PRISMSS Natural Enemies, Natural Solutions (NENS) team (Dr Quentin Paynter and Dr Lynley Hayes) was in Rarotonga in mid-June to monitor the spread of the African tulip beetle (Paradibolia coerulea). This beetle was introduced in 2022 in an effort to control the African tulip tree which is considered one of the world’s 100 worst invasive species and is widespread in Rarotonga. After conducting their monitoring checks, the PRISMSS NENS team were delighted to report that the African tulip beetle is exceeding their expectations. Signs of the beetle were found at all five release sites, with a lot more damage than in June 2024 when the NENS team were last on island. Every sized scale of the African tulip tree, from small plants to large trees, in the sun and the shade, are being attacked. There was an especially noticeable increase in the number of adult beetles and damage at Ngai Taporoporo o Takitumu, also known as the Takitumu Conservation area (TCA). Moderate damage was common on all plants inspected up to 500m away from the release point. The beetles are dispersing well as the NENS team found signs of them on most plants checked all around the island, even on isolated plants around town. Given most of the beetle releases were only made in 2022, their performance at this early stage bodes extremely well for successful biocontrol of African tulip tree (Spathodea campanulate). Damage from the gall mite (Colomerus spathodeae), which is also extremely common, is complementing the beetles. Galling ranges from slight to heavy with some significant damage to growing tips observed.
PRISMSS NENS Programmatic lead for the Pacific, Mrs. Lynley Hayes of Manaaki Whenua Landcare Research (MWLR) highlighted that “the Cook Islands is leading the way with using natural enemies to control African tulip tree in the Pacific. The release of the African tulip beetle in Rarotonga in 2022 was a world first. The beetle is exceeding expectations in terms of how quickly they are dispersing around Rarotonga and building up damaging populations, which augers well for successful control of African tulip tree in coming decades”. Hayes also noted that MWLR have plans to release the beetle in Fiji, Samoa, Tonga and Vanuatu before the end of 2025.
The Pacific Regional Invasive Species Management Support Service (PRISMSS) supports countries and communities to take action to address invasive species threats to Pacific Island ecosystems and resilience. PRISMSS, which is managed by the Secretariat of the Pacific Regional Environment Programme (SPREP), engages with experienced partners in the region and in-country staff to deliver activities aimed at restoring island resilience by managing invasive species. Manaaki Whenua Landcare Research of New Zealand is the PRISMSS partner who leads the Natural Enemies, Natural Solutions program, which focuses on using species as natural solutions to manage other invasive plants or animals.
See the Natural Enemies Natural Solutions Facebook page for updates on biocontrols across the Pacific: https://www.facebook.com/PacificNENS
