Bay of Plenty Regional Council has released the first biological control to attack the invasive weed woolly nightshade.
Council staff have released 300 lace bugs on a badly-infested forestry block in the Tauranga area.
The bugs feed on the leaves of the plant, stunting its growth.
Woolly nightshade is well-established in the North Island.
It can take over pasture and crowd out other vegetation, is thought to be poisonous to stock and can also make people sick.
The bugs were imported from South Africa and bred in New Zealand for three months before their release.