Control of Invaders

Abstract

Invasions of organisms have been of great concern to those involved in the various aspects of food and fiber production. In many cases, introduced species have been deliberately released, such as most of the plants used in commercial agriculture and the parasitoids and predaceous insects that are used in classical biological control attempts. However, many invaders are accidentally introduced, such as insects and pathogens, and many of these are a threat to commercially important commodities. Of the 444 species of insects and mites listed by Metcalf et al. (1951) as crop pests in the United States, it is estimated that approximately 36% of them are introductions (van den Bosch 1971). Many applied scientists, pest managers, and growers or producers spend much of their time concerning themselves with controlling pests, many of which are invading species. Usually the well-established invaders are treated as native pests and conventional control techniques are used. On the other hand, some pest management strategies have been developed to deal specifically with invading species and these are eradication and classical biological control. In many cases, the biology and ecology of the invaders is poorly understood and as a result the control programs are poorly conceived. This is particularly true with eradication programs.