In the vibrant heart of the Pacific, Papua New Guinea (PNG) is home to some of the world’s richest biodiversity but beneath the canopy and across the gardens, a quiet threat is spreading. Invasive weeds, fast-growing, aggressive plants which are not only growing “a mile-a-minute” but are undermining livelihoods, impacting ecosystems and costing the economy.

For communities who rely on subsistence farming, invasive weeds are relentless as they invade food gardens, smother crops and force farmers to spend hours clearing land that once flourished naturally as grazing lands are overrun, livestock suffer, and traditional practices are disrupted. Biological control of weeds in PNG has made significant strides, particularly in tackling invasive species like Chromolaena odorata, a fast-spreading weed that affects plantations, food gardens and grazing lands.

PNG has been a regional leader in the use of natural enemies to suppress invasive weeds and over the years, 19 biocontrol agents have been released to target species like broomweed (Sida spp.), giant sensitive plant (Mimosa diplotricha), lantana (Lantana camara), salvinia (Salvinia molesta), and water hyacinth (Pontaderia crassipes).

Over the past decade, PNG’s progress in invasive species management slowed due to shifting national priorities and constrained funding but is now reigniting its leadership in this space through renewed engagement with the Secretariat of the Pacific Regional Environment (SPREP) led Pacific Regional Invasive Species Management Support Service (PRISMSS), specifically its Natural Enemies – Natural Solutions (NENS) programme. Group photo

This is supported by the PRISMSS Restoring Island Resilience (RIR) project, funded by New Zealand’s Ministry of Foreign Affairs and Trade (NZMFAT) and the United Kingdom’s Foreign, Commonwealth & Development Office (UK FCDO).

The Manaaki Whenua Landcare Research (MWLR) group of the New Zealand Bioeconomy Science Institute leads the NENS programme which provides support to Pacific Island Countries and Territories to restore ecological balance using safe, targeted biocontrol agents from the weeds’ native range.

In September, MWLR hosted a scoping mission and a one-day National Stakeholder Workshop in Port Moresby, bringing together 30 participants from eight key organisations including the Department of Agriculture and Livestock (DAL), National Agriculture Research Institute (NARI), Conservation and Environment Protection Authority (CEPA), University of PNG, Binatang Research Centre, youth awareness groups Eda Davara and Mastermind, and the Women and Youth in Agriculture networks. Workshop

Mr Heai Steven Hoko, Deputy Secretary, Departments of Agriculture and Livestock (DAL), PNG commented, “Papua New Guinea is working towards making agriculture the engine of socio-economic growth, with a goal of creating one million jobs and generating K30 billion by 2033.”

“To achieve this, we must adopt innovative and sustainable practices that improve food security, raise incomes, and drive commercialisation of agriculture and livestock.”

“Weeds, like insect pests and diseases, directly reduce yields and threaten these ambitions but the NENS programme offers a vital, sustainable approach to protect crops, strengthen production, and build capacity across our agriculture and natural resource sectors. We look forward to working in partnership to deliver long-term solutions for PNG.”

Ms Anastacia Kawi, Regional Plant Protection Officer reflected, “during my work from 2008 to 2016 on the mass rearing and release of Puccinia spegazzinii to control mile-a-minute, I saw first-hand how invasive weeds directly impact farmers and communities.”

“Biocontrol offered real solutions then, and the NENS programme now provides an important pathway to protect crops, improve production, and safeguard our agriculture into the future.”

“With my knowledge, skills, and years of experience in biological control of invasive weeds, I look forward to collaborating with NENS through the PNG project to share expertise, impart skills, and mentor the next generation of plant protectionists in PNG and across the Pacific.”

PRISMSS NENS Technical lead for the Pacific, Ms. Lynley Hayes said, “the level of engagement and enthusiasm at the workshop was very encouraging and we thank DAL for their support and extend our gratitude to all the organisations that participated in this event. We look forward to working with them in the future.”

“This workshop was an important step in reconnecting partners, reviewing previous work and prioritising weeds for future biocontrol action,” added NENS Co-ordinator Ms Annette Mwayawa.

“The top 6 weeds identified as priorities for NENS in PNG were pig weed (Mimosa pigra), mile-a-minute (Mikania micrantha), African tulip tree (Spathodea campanulata), Koster’s curse (Miconia crenata), spiked pepper (Piper aduncum), and molasses grass (Melinus minutiflora).”

The SPREP Invasive Species Adviser, Mr David Moverley commented that, “the work of the PRISMSS NENS programme is providing opportunities for many Pacific island states.”

“This is particularly evident with the work on African tulip tree, which is widespread across the region and is problematic everywhere it has been introduced, but by addressing it through a regional focus, we are confident that the cost per state of natural enemy introduction can be minimised.”

“Invasive weeds don’t just threaten crops they threaten Pacific cultures. When land becomes unusable, traditional knowledge, food practices and community cohesion suffer but by investing in smart, scalable weed management, PNG can protect its heritage and build resilience against climate change through the PRISMSS NENS programme.” NENS

With PNG expressing interest in the NENS programme, the number of countries involved rises to ten including the Cook Islands, Fiji, Marshall Islands, Niue, Samoa, Solomon Islands, Tonga, Tuvalu, and Vanuatu.

The PRISMSS NENS programme with its partners will continue to support Pacific island countries by providing technical expertise, capacity building, coordinating regional weed management strategies, scaling up proven biocontrol solutions and empowering communities to lead local action.

About PRISMSS: The Pacific Regional Invasive Species Management Support Service (PRISMSS) is a coordinating mechanism designed to facilitate the scaling up of operational management of invasive species in the Pacific. PRISMSS, which is led by the Secretariat of the Pacific Regional Environment Programme (SPREP) brings together experts to provide support within the Pacific region with a focus on protection of indigenous biodiversity and ecosystem function. As a service provider, PRISMSS provides a comprehensive suite of support services in a cohesive, effective, efficient, and accessible manner to Pacific Island countries and territories.

Restoring Island Resilience (RIR): The PRISMSS - Restoring Island Resilience (RIR) is a New Zealand-PRISMSS collaboration project that aims to improve Pacific Island Countries and territories livelihoods and resilience to climate change by reducing the impact of invasive species on natural and agricultural ecosystems through the six PRISMSS programmes.

PRISMSS Powered by: New Zealand Foreign Affairs & Trade, UK International Development, GEF, United Nations Environment Programme & SPREP.

PRISMSS Partners: Birdlife International, Earth Sciences New Zealand, New Zealand Department of Conservation, Island Conservation, Manaaki Whenua Landcare Research group of the New Zealand Bioeconomy Science Institute, the Pacific Community and SPREP.

PRISMSS Programmes: Natural Enemies Natural Solutions (NENS), Predator Free Pacific (PFP), Protect Our Islands (POI), Protect Our Marine Areas (POMA), Resilient Ecosystems Resilient Communities (RERC), War On Weeds (WOWs).

For additional information please contact Mr Dominic Sadler, PRISMSS Manager on dominics@sprep.org or Mr Nitish Narayan, PRISMSS Communications & Liaison Officer on nitishn@sprep.org