Pheromones To Manage Pests

CSIRO research has reported that 90% of chemical insecticides have been eliminated from commercial orchards as commercial stone fruit growers use the pheromone method to disrupt the mating of insects.

Insects such as the oriental fruit moth are guided to their mates by chemical sex attractants called pheromones, released by the opposite sex. Scientists are identifying the unique pheromone for the insect pest they want to control, and the amount of pheromone needed to disrupt mating or entice moths into traps for monitoring.

The pheromone is loaded into different types of tubing, which can either be tied to orchard trees or placed in simple traps made from milk or orange juice cartons coated with a sticky substance. As the pheromone permeates through the walls of the tubing it is carried on air currents through the orchard. The male either becomes confused and doesn't know which direction to turn for the female, or he becomes desensitised to the lower levels of pheromones naturally given out by the female and has no incentive to mate with her.

Although it is still not clear how mating disruption actually works, the male moths do not find the females nor do they mate, and any eggs the female lays are infertile.

There are a number of advantages in using pheromones to disrupt mating, especially with many insect pests becoming resistant to pesticides. In the absence of the insecticide that controlled the moth, the natural enemies of the two spotted mite were able to control this pest as well.

Pheromones can be used to trap, monitor or control insect pests. Pheromone traps are extremely sensitive and can be useful in detecting the entry of unwanted exotic pest species as well.

Currently, a detection system using pheromone traps is in place for the Asian Gypsy Moth. The traps have now been set up in ports and other potential points of entry around the east coast of Australia, and along the south coast as far as Western Australia.

In an effort to reduce the use of pesticides, CSIRO researchers are continuing to explore ways of using pheromone to control the insect pests.