Lightbrown apple moth biological control

Lightbrown apple moth is attacked by a wide range of predators, parasitoids, and some diseases. However, these benefical species have never been the primary method of control in commercial orchards. This is because lightbrown apple moth is a quarantine pest and must be controlled to extremely low levels. Natural enemies are rarely effective in controlling pest populations at these low densities. However, with the introduction of more selective insecticides, such as insect growth regulators, and the increase in organic production, the natural enemies of lightbrown apple moth and other leafrollers have become more important. Classical biological control of lightbrown apple moth (an Australian species) in orchards was attempted in New Zealand in the 1920s through the introduction of the parasitoid Goniozus jacintae from Australia, although it is now thought that it was already present in the country. More recently, the objective of introducing natural enemies from Australia has been to reduce the large populations of lightbrown apple moth occurring on its more than 250 host plants in the environment. This could minimise immigration of moths into orchards and reduce the need for chemical control. A major programme of introducing natural enemies from Australia was conducted in the 1960s and 70s.

Insect pathogens, such as bacteria and viruses, offer an alternative method of biological control. They can be formulated as sprays and applied to apple trees using conventional spray machinery. The bacterium Bacillus thuringiensis is widely used for control of lightbrown apple moth. A nucleopolyhedrosis virus of lightbrown apple moth has also been field tested.

Another biological method of controlling lightbrown apple moth is mating disruption, which uses high concentrations of the insect pheromone to prevent mating.