Integrated pest management
Box 2 | Integrated pest management in the Australian apple industry
Australia's apple industry is affected by a number of potentially damaging pests, including the codling moth, the light-brown apple moth and the two-spotted mite. In the past, the industry has relied mainly on pesticides to control such pests.
In the late 1940s, a new synthetic insecticide called dichloro-diphenyl- trichloroethane (DDT) was used to control codling moth. Despite early success against the codling moth, it had some drawbacks. For a start, it led to an increase in the light-brown apple moth and the two-spotted mite, probably because it removed beneficial species that had previously kept these pests under control. Eventually, the codling moth also became resistant to DDT, so farmers switched to other insecticides. Scientists began looking for non-chemical alternatives, and a small number of farmers became interested in integrated pest management strategies.
But the turning point for the apple industry probably came in 1989, when research revealed that daminozide, a chemical used to regulate the shape and maturity of Red Delicious apples, was a potential carcinogen (cancer-causing agent). This rocked the industry, which almost immediately started developing a strategy to reduce the level of all chemicals used in apple production including pesticides.
Towards integrated pest management in the apple industry
A key challenge has been to find a way of reducing codling moth populations without destroying beneficial insect predators at the same time. A biological control called the codling moth granulosis virus was investigated. Although successful in Europe, this virus has so far proved disappointing in Australia. Other techniques tested with varying degrees of success include mating disruption, biological control with a parasitic wasp, and more effective timing of pesticide applications due to improved monitoring.
With the reduced use of insecticides for the control of codling moth come other benefits. For example, the introduced predator of the two-spotted mite is able to survive, multiply and eventually reduce the population of the two-spotted mite.
More research on integrated pest management in the apple industry is currently underway. The situation is complicated by the fact that there is more than one significant pest. Researchers and farmers face the challenge of integrating techniques to ensure that attempts to control one pest don't prejudice attempts to control another.
Posted March 1999.