The shade-tolerant Tradescantia fluminensis prevents native regeneration by smothering a forest floor.
Weed Action is fortunate enough to have a thriving nursery site of ‘shiny’ (Neolema ogloblini) a bio-control agent for the invasive ground cover Tradescantia (Tradescantia fluminensis), located at Reotahi. In January 2020, we arranged another round of distribution where members of the community could ‘pick their own’ small population and translocate them to areas where Tradescantia is a problem. People collected around 100 leaf-eating beetles with the hope that they feel at home in their new surrounds, proliferate and gorge themselves silly to keep this weed in check. The bio-control agents are particularly popular with residents and although they are not a silver bullet or a tool for eradication, there are a couple of benefits of utilising them. For one, Northlander’s can do with all the help we can get when it comes to weed control. We live in paradise and we aren’t the only organism that prefers life in this Goldilocks zone either. Many pest plants have found the conditions in Northland ‘just right’ and have managed to spread in a relatively short period of time creating devastation in our native bush and costing communities time and money with control efforts. We are happy to receive any tool in the arsenal in this constant battle. We are also keen to reduce the amount of herbicide we put on our land, with Tradescantia being difficult to manually control. Weed Action views herbicide as a necessary evil at times and are constantly looking to improve control methods to empower and educate our community to lessen the impacts to environment and self. The bio-control beetle would be of benefit in a situation where the terrain is steep, or the site has limited access or if you have a large property where Tradescantia is just one of many environmental pest plants present.
‘Shiny’ bio-control beetle.
When the newly translocated beetles are released at their new homes, in autumn we expect to see them quieten down to the point where they could be mistaken for not being present or dead. However, when the weather warms, we will be able to see them happily sitting on top of the leaves and it’s not long before damage from leaf browsing will appear. If they are situated in a relatively warm area, the population will increase, the Tradescantia will lose vigour and the beetles may migrate to near by patches of the weed.
We also have another nursery site for another beetle that likes to feed on Tradescantia: ‘knobbly’ (Lema basicostata). This beetle was released at the end of autumn last year and we are patiently waiting for the numbers to build before they are ready for distribution at the Heads. If you are interested in your own population of shiny – the leaf eating beetle then email Weed Action WH at info@weedaction.org.nz or call our Project Coordinator Kelly Maxwell o 021 0233 2005 to be placed on the waiting list until summer.
