Plant Health

The Pacific’s fragile ecosystem is constantly at risk from invasive species, pests and diseases. It is therefore vital that sustainable and appropriate management practices are developed and utilized to ensure   sustained productive use of the land. Plant Health aims to promote these practices by utilizing its three main units, entomology, pathology and weeds in undertaking regular surveys of pests and diseases, providing information, creating awareness among farmers,  updating information databases and assisting in eradication activities. 

Stakeholder consultation to develop a sub-regional project on invasive weeds
Wednesday, 04 December 2013 07:54
International experts on the biological control of invasive weeds met in Nadi (25–27 November 2013) to review current regional work on the management of troublesome weeds in agricultural and natural environments, with the aim of developing a sub-regional project for the Melanesian countries – Fiji, Papua New Guinea, Solomon Islands and Vanuatu.

The three-day consultation will lead to the development of a proposal for funding by the Australian Centre for International Agricultural Research (ACIAR). The project is expected to be launched next year by the Secretariat of the Pacific Community and the Queensland Department of Primary Industries, in collaboration with national stakeholders in the four countries.

The proposal to develop a sub-regional project follows on from the successful completion of a pilot project on the biological control of the invasive mile-a-minute weed (Mikania micrantha) funded by ACIAR and implemented by SPC for PNG and Fiji. The project identified and released a biological control (a fungal rust species) which is now established – a success story in releasing a natural enemy to manage an invasive weed.

In his opening remarks, Richard Markham, ACIAR Program Manager for Pacific Crops, said that sustainable weed management is critical to maintaining the integrity of agrobiodiversity and the productivity of cropping systems in Pacific islands.

'In biological control, much of the work of our profession is concerned with screening biological control agents, looking at their effectiveness in controlling the target species but also, and perhaps above all, minimising the risk of these new and intentionally introduced species causing damage to non-target species.

'The principle and process of introducing natural enemies has sometimes been perceived as bringing biological control practitioners into conflict with conservationists. Experience in South Africa has, however, shown that classical biological control can serve almost as the proverbial silver bullet to selectively knock out, or to reduce the vigour of, invasive species that are threatening biodiversity in vulnerable native plant communities.'

Richard said it is equally important, after releasing a biocontrol agent, to go back and assess the socio-cultural and environmental impact of the biocontrol effort. Unfortunately, not all projects make provision for this vital follow-up.

Workshop facilitator, Michael Day, Senior Entomologist with Queensland Department of Agriculture, Fisheries and Forestry, had previously collaborated with SPC on the Mikania project, alongside Mr Warea Orapa, former SPC weed specialist and now deputy director at PNG National Agriculture and Quarantine Inspection Authority. A proposal for a regional biological weed control project was first flagged at that time.

New Zealand assistance in the past has helped with capacity development in biological control. In 2009, New Zealand hosted a large gathering of regional expertise on biological control of weeds, providing the platform for this new effort. Colleagues Sarah Dodd and Quentin Paynter reported the launch of an NZAID-funded weed biological control project targeting eight weed species in Cook Islands. In addition, the project aims to conduct DNA testing to identify the origins of a spreading invasive weed, Merremia peltata, which is also a problem in the Melanesian countries and could become a target of the new effort.

Hawaii Department of Agriculture representative, Darcy Oishi shared his experiences as an international leader in the use of biological control for positive economic and environmental outcomes. Some of Hawaii’s prominent work in biological control started in the early 1900s with lantana weed. Thirteen insect species were released to control the weed and nine established. It cannot be said that the lantana problem has been entirely solved but at least this weed is much less of a nuisance.

David Moverly and Posa Skelton from the Secretariat of the Pacific Regional Environmental Programme (SPREP) shared their experiences working on a Global Environment Facility-funded multi-country weed management project that is currently under way in the Pacific. The presence of SPREP at the consultation highlights the significance of weeds as a problem causing economic losses in agriculture and forestry: invasive plant species in natural habitats also pose a threat to native biodiversity.

Prospects for the biological control of the African tulip tree were presented by Stefan Naser, who was contracted by SPC a few years ago to conduct biological exploration in the area of origin of this species – equatorial Africa. Brought to the Pacific islands as an ornamental many years ago, the African tulip tree has spread far and wide, invading farmland and pasture areas. Farmers in Pacific islands find the thickets of trees that form on fallow plots very hard to clear when they are ready to plant their crops. In Africa, many insects feed on the tulip tree, keeping its population in check. Carefully introducing a few of these insects that are adapted to feed only on the African tulip tree could help to tame this plant's excessive vigour and invasive properties in the Pacific. Stefan also shared a wealth of knowledge on various biological control projects he had worked on in South Africa.

A leading Fiji environmental advocate group, Nature Fiji, represented by Dick Watling, provided a conservationist view of the impact of introduced biological control on native fauna and flora. He remarked that many researchers have found that the Pacific islands provide a wonderful natural laboratory for scientific enquiry – but the consequences for the environment have not always been positive. He cautions international stakeholders to take heed of due process when planning releases of biocontrol agents. He pointed out that, although the African tulip tree (Spathodea campanulata) is considered invasive and takes over native flora in natural habitats, it provides valuable ecosystem services, including the initial reforestation of hillsides denuded by incautious burning.

Casting the net at the consultation to gather views from a wide range of stakeholders, and understanding and accommodating their concerns, contributed to arriving at decisions based on scientific evidence and consensus-building. A list of top priority weed pests for national activities and another list of priority pests for long-term research were drawn up at the end of the three-day consultation.

For more information, please Emil Adams ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it ).


Effective management can help maintain productivity of land resources,stregthen food security, safeguard the environment and increase revenue. Plant Health strives to improve awareness on environmental implications of agricultural practices and offering safer environmentally friendly options.