Advances in the control of locusts (Orthoptera : Acrididae) in eastern Australia: from crop protection to preventive control

Locusts can form dense bands and swarms that can cause substantial damage to pastures and crops. For many years, State Departments of Agriculture aimed to protect crops by conducting locust control programs in their agricultural areas but in recent years the Australian Plague Locust Commission (APLC) has conducted preventive control programs that begin in locust source areas in the interior. The current preventive control programs are the culmination of more than 70 years of continuous research, conducted for many years by CSIRO and State Departments of Agriculture and more recently, by the APLC. Early research followed the sequence of outbreaks in agricultural areas but by the 1960s, there was increasing evidence that locusts commonly bred in the interior and then migrated to agricultural zones. These migrations covered long distances, often from one state to another and in 1974 the APLC was established with the specific mandate to control locusts that posed an interstate threat. The rationale was for the APLC to control locusts both at source in the interior as well as in the agricultural zone. Controlling locusts in the interior had never been attempted before and an intense research program was initiated as part of APLC operations that has culminated in the current preventive locust control programs. Preventive control involves early intervention, where treatment begins with localised populations present early in breeding sequences and continues every generation thereafter. To rapidly locate and control localised locust infestations over a large part of eastern Australia, a Decision Support System for locust management was developed that integrates data from a wide variety of sources to help operations staff determine when and where to concentrate survey and control efforts. When threatening locust populations are detected, control teams can be rapidly deployed to wherever treatment is required. An integral part of locust control programs is limiting environmental and monetary costs so that an important component of APLC research has been to focus on reducing chemical use by using the lowest effective dose and by using products that can be applied in barriers 300-500 m apart so that only a small proportion of the area is sprayed. Increasing constraints on insecticide use, including the production of organic beef in locust source areas, has led to the development of a biological alternative. The latter program led to nearly 25 000 ha of locusts being treated with the biological agent Metarhizium during the 2000-01 locust season, the first large-scale operational use of this biopesticide anywhere in the world.