Prospects for the future development and application of the sterile insect technique

Abstract

Science-based modern agriculture and international trade in agricultural commodities have achieved that, even though the world population has doubled in the last 40 years, the absolute number of people in poverty and hunger has been falling steadily. The major challenge in the immediate future is to consolidate these positive gains, while simultaneously expanding environment-friendly agricultural practices. Within this context, the sterile insect technique (SIT), as part of area-wide integrated pest management (AW-IPM) programmes, will continue to gain momentum for application against certain key insect pests. This is in response to the demands for cleaner food and a better environment, the need to facilitate increasing international trade by overcoming pest related trade barriers to the movement of agricultural commodities, and the imperative of dealing with the increasing invasion of exotic pests. As the use of the technology increases, changes will continue to be made to improve the overall efficiency of the technique for those species where the SIT is already being used, and to expand the use of the technique to new key species. Modern biotechnology may also contribute to improving efficiency and, even though there are as yet no transgenic strains of pest insects that could be used in AW-IPM programmes, transgenic technology may eventually benefit these programmes in terms of strain marking, genetic sexing, molecular sterilization, and disease refractoriness; however, first the regulatory hurdle to allow their use will have to be overcome. There appears to be much promise in improving sterile male performance by exposing male insects to hormonal, nutritional, microbial, and semiochemical supplements. Furthermore, the management of mother colonies will be significantly improved to reduce the effects of colonization and to slow down mass-rearing effects on key behavioural parameters that often result in rapid colony deterioration. Progress will also need to be made in the cost-effectiveness of all components of SIT implementation, from cage design to facility design, and from programme planning to evaluation. The trend of increasingly using sterile insects for routine pest suppression rather than eradication, particularly in commercially important commodities, will favour the involvement of the private sector and hence accelerate these improvements. Commercial producers of beneficial insects will probably be the natural investors, in view of the complementarities with sterile insects, experience in managing living organisms, and understanding the biological control market. As programme implementation is logistically complex, management will remain the key issue determining the success or failure of any area-wide approach to insect control. Thus, in spite of the many successes achieved and to be expected, in many least-developed countries the SIT may be a technology that is ahead of its time and beyond the animal and public health as well plant protection infrastructures. Failures in SIT application, mostly confined to such countries, have not been due to science but the implementation of systematic large-scale operations. Increased involvement of the private sector in such countries probably would assure effective implementation.