About the project
The weed Tradescantia (Wandering Willie) is a significant problem in Northland and causes massive damage in natural areas by smothering native seedlings and preventing bush regeneration. The weed is currently managed on farmland by grazing stock often on margins of land near waterways, wetlands and in natural bush/forest areas. Allowing stock to graze these areas results in nutrients and sediment entering waterways and native seedlings being eaten or trampled. Living Water is partnering with Landcare Research and Northland Regional Council to test the effectiveness of three different species of Brazilian beetles to control Tradescantia, giving landowners a cost-effective alternative control method while they continue stock exclusion fencing to restore native forest remnants.
Cost effective weed control for farmers in fenced native forest remnants
Much reduced competition for native plants promoting regeneration
The three-year trial began in December 2015 with the release of 300 beetles in five sites across the Hikurangi Flood Plain.
Initial results show beetle larvae are stripping leaves bare and remaining leaves are being well-chewed by adult beetles.
Anecdotal evidence suggests that rainbow skinks (Australian invasive species) may be eating some beetles - attempts to confirm and measure the impact of this are underway.
The February 2019 survey indicated a healthy population of beetles probably due to the warm dry summer weather.
Project Concept and Planning
Completed December 2015
Project Implementation and Monitoring
Started in December 2015 and due to end in 2019
This three-year project has been fully completed. Manaaki Whenua/Landcare research has provided a final report on the biocontrol trial release of three species of beetles at sites within the Hikurangi Floodplain of the Wairua River.
Results indicate the beetles have reduced tradescantia cover, although the experiment needs to continue for several years before noticeable ecological benefits are seen.
Report include guidelines on collecting and establishing populations of these biocontrol beetles in the hope that others will take up the challenge to control this very invasive weed