Officials in Northland are trying to reduce guava moths by exhausting and confusing the males with female pheremones.
The guava moth is thought to have blown across the Tasman in the 1990s, and ruins nut crops and fruits such as feijoas.
Residents in an eight-hectare area in Whangarei are involved in the 14-month trial in efforts to disrupt the moth's mating cycle.
They are attaching twisty ties impregnated with female hormone to their fruit trees.
Northland Regional Council's senior biosecurity programme manager, Don McKenzie, says it's hoped the hormones will confuse the male moths into chasing a mythical female until they become exhausted - and die.
Mr McKenzie said the ties are not expected to kill off the populations, but could reduce their number.