Sterile Insect Technique (SIT) for Fruit Fly Control – The South African Experience

Abstract

Development and implementation of the Sterile Insect Technique (SIT) in South Africa began in the mid 1990s with Phase 1 to evaluate the feasibility of eradicating Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), in export table grapes in the Hex River Valley, Western Cape Province. Since then the SIT programme has progressed through a further two phases. During these phases the scale and cost-effectiveness of the production of high-quality sterile male flies for release has improved significantly. Additional areas with different fruit crops have been incorporated and the relative efficacy of aerial and ground releases evaluated. Overall, C. capitata SIT in South Africa has been more successful in some areas than in others, but the programme continues to evolve based on the many valuable lessons that have been learnt. For SIT to be effective there must be sustained funding, no compromise in quality, and good management, communication and training for the staff involved. There must be buy in from the growers to ensure that SIT runs alongside other management strategies and orchard sanitation. Rather than eradication, the programme focus is now population suppression in a limited number of production areas. In the long term we aim to increase the area under SIT, returning to aerial releases of sterile C. capitata, creating areas of low fruit fly prevalence, and possibly fruit fly-free areas. This could lead to a sustainable international fruit market without the need for fruit fly trade restrictions.