Credibility of an IPM approach for locust and grasshopper control: The australian example

Abstract

In Australia, locusts are controlled using an Integrated Pest Management (IPM) system that aims to find and rapidly treat most gregarious locust populations. Many outbreaks have significant breeding in the arid interior of Australia during summer and treatments begin in the interior, to keep locust invasions of the agricultural zone to manageable levels. This preventive control program relies on IPM: moderately accurate forecasting and rapid response survey, followed by treatments of bands and swarms with a range of proven readily available products. IPM begins with a Decision Support System that uses data on weather and previous locust distributions to model locust development and possible migrations, so as to provide moderately accurate forecasts as to when and where locusts are likely to be present. When locusts are reported or forecast as likely to be in a region, surveys are conducted to locate any infestations and if bands or swarms are found, they are rapidly treated using a variety of techniques. Bands are commonly visible from an aircraft flying overhead and when bands are seen, the areas containing bands are normally treated using "barrier" treatments of fipronil, where synthetic insecticide is applied every few hundred meters. Swarms are located by helicopter and sprayed, using fast-acting organophosphorous compounds like fenitrothion. But an increasingly important part of IPM in Australia is having an environmentally friendly option. Locusts can then be treated even if they are found where synthetic insecticides cannot be used such as near waterways, where there are rare and endangered species, or on organically managed properties. It was the switch to produce organic beef for Japan by a number of properties in locust breeding areas in the interior that was an initial driver for the development of an alternative to synthetic pesticides for locust control in Australia. The result of an intensive research and development program was the mycopesticide Green Guard, which has as its active ingredient the FI-985 isolate of the fungus Metarhizium anisoplae var.acridum. Green Guard has played an important part in the IPM of locusts and grasshoppers in Australia, including large-scale control operations, with more than 100,000 ha treated since operational use began in 2000. However, while Green Guard plays an important part in the IPM of locusts and grasshoppers, it still accounts for only about 10% of the area treated. Green Guard costs more than synthetic insecticides and locust and grasshopper mortality is delayed when temperatures are mild. An additional factor limiting its use is a lack of biological control products for most other pests, so that synthetic insecticides are still used in most cropping systems, resulting in residues being present in most products and in most environments. As restrictions on synthetic pesticides generally increase and biological alternatives become more available, it is expected that Green Guard use should expand to become an increasingly important component of locust and grasshopper IPM.