Bay of Plenty Regional Council has released 300 lace bugs to attack the invasive weed woolly nightshade in a badly-infested Tauranga forestry block.
The South African species feed on the leaves of the plant, stunting its growth.
Widespread in the North Island, woolly nightshade can take over pasture, and potentially make livestock and people sick.
It is the first time biological control has been used for the plant, which has infested about 70ha of a forest in Welcome Bay.
The regional council manager of land management Warwick Murray said the council hoped the 5mm lace bugs - native to South America - lay up to 900 eggs each.