KEY POINTS:
Scientists will trial a promising new compound in the battle against the invasive pest algae didymo early next year after gaining resource consents for two test sites in Southland.
The formulation devised by National Institute of Water and Atmospheric Research scientists in Christchurch has proved effective against didymo, or rock snot, in laboratory tests.
Biosecurity New Zealand, the lead government agency tackling the highly invasive Northern Hemisphere pest, has been awaiting consents before trials with the copper-based compound.
In the laboratory, the formulation has proven to be effective in killing slimy didymo cells while having a low toxicity to fish and little effect on other organisms.
Since first being found in a Southland river in October 2004, didymo has infected 27 South Island waterways. It has not yet been detected in the North Island and Biosecurity NZ is determined to keep it contained in the south.
Biosecurity NZ spokesman Phil Barclay said receiving resource consent for the trials from Environment Southland last week was the "highlight of the year" in the battle against didymo.
Trials at two sites would start next month.
Scientists had been pleased with dye trials on a dispersion method for the formulation that had been done in a river near Rotorua.
"The next stage is testing the formulation in a river environment to make sure it's as effective as they hope it may be, and also that it doesn't have a harmful impact on other organisms," Mr Barclay said.
Scientists have emphasised the formulation should not be seen as a "silver bullet" and is unlikely to eradicate didymo, but it may become an effective control mechanism.
Environment Southland consents manager John Engel confirmed that consents had been granted for two sites in the Waiau catchment - a tributary of the Mararoa River and a tributary of the Waiau River, the main river immediately east of Fiordland National Park.
- NZPA
