The Pheremone Breakthrough

Surveillance of white-spotted tussock moth in the first year of the eradication programme was hampered by the need to use caged live female moths in traps to attract males. A major breakthrough was the development of a synthetic pheromone (sex attractant) used for the first time in the 1997-98 high density trapping programme.

The synthetic pheromone was developed through an intensive, year-long research project by Canadian and New Zealand scientists. Field trials using the pheromone in tussock moth's native Japan netted excellent catches. While the lures were being loaded inside the scientists' car, male moths were beating on the windscreen. And male moths entered the traps even before they would be hung on trees.

The trials in Japan also provided scientists in New Zealand with excellent information about the amount of pheromone required and the density of trapping likely to yield the best results.

How do pheromones work?
Pheromones are chemicals emitted by living organisms to send messages to other organisms of the same species. They are emitted particularly by the female of the species to attract a male at mating time.

Synthetic pheromones have been developed for many insect species, particularly to identify what insect pests are present in crops.

In the tussock moth trapping programme a small amount of the pheromone is contained in a polyethylene vial within a cardboard trap. The vial will be replaced every four weeks.

What does the pheromone contain?
The tussock moth pheromone, (Z)-6-heneicosen-11-one, is identical to the naturally occurring compound found in the female white spotted tussock moth. Similar pheromones have been sued extensively both in trapping and in moth mating disruption strategies overseas.

How effective is the pheromone?

During high density trap surveillance, each new batch of pheromone was tested as it arrived in the country. These tests, conducted in a field cage and using live male moths, showed the synthetic pheromone is up to six times more effective than life females.

Is the pheromone likely to harm humans?
Similar pheromones have been tested by the Forest Science Laboratory, United States Department of Agriculture and found to be non-toxic. Auckland Healthcare's September 1997 Health Risk Assessment of the tussock moth eradication programme concluded that there would be no risk of health effects from swallowing, inhaling or touching the pheromone to be used in the Auckland programme.

Will other moths be attracted to the traps?
It is highly unlikely that moths of other species will find the chemical contents of the pheromone attractive and get caught in the traps.

Page last updated: 30 April 2008