Often known as ‘cutty grass,’ pampas is an invasive weed from South America, which threatens NZ’s native toetoe. The weed also poses a threat to forestry and kiwifruit farms because of its aggressive nature and ability to affect ecosystems.

Landcare Research is now carrying out further testing at their biocontainment facilities to assess the suitability of the fungus and insects, including whether they will only affect pampas.

MPI Acting Director Aquaculture, Growth and Innovation, Alice Marfell-Jones, says this initiative, supported through the Sustainable Farming Fund, is a worthy investment as the research benefits the primary industries. “We are very aware that pampas is a shared problem, and saw value in committing $335,000 in to the project. The weed affects forestry and kiwifruit growth and it’s important we (MPI) play a role in protecting and growing these industries.”

Landcare Research traced the pampas back to its South American origins in what Science Team Leader, Lynley Hayes, refers to as a ‘needle in a haystack’ search. “We were quickly able to confirm that New Zealand purple pampas (Cortaderia jubata) comes from Ecuador/Peru. However, finding the origins of common pampas (Cortaderia selloana) was more difficult, but we eventually managed to find an exact genetic match with some plants next to a soccer field in Chile. Surveys in these regions of South America revealed three potential control options worthy of further study; a black smut fungus and two planthopper insects.

“The black smut fungus attacks the pampas flowers, affecting reproduction. The planthopper insects damage the plants leaves, and secrete a honeydew that impairs the plants ability to effectively photosynthesise.”

Although the Sustainable Farming Fund project has come to an end, the initial objective of finding possible biocontrols for pampas has been achieved. Further testing on both potential options is continuing.

“If our further research can answer some lingering questions and the agents continue to show promise, we will seek further funding for the process of introducing them to New Zealand. We are grateful for the Sustainable Farming Fund grant we received for this project as it was vital and extremely valued,” Hayes said.

The Ministry's Sustainable Farming Fund invests in applied research and extension projects that tackle a shared problem or develop a new opportunity in the Primary Industries.

The total cost of the project was close to $600,000 and was co-funded by Future Forests Research, National Biocontrol Collective, Forest Health Research Collaborative, NZ Transport Authority, Kiwifruit Industry, LINZ and Treescapes.

Photo: Image on the left shows the effect of black smut fungus on pampas. Image on right is a planthopper insect on pampas grass.