The medfly program in Guatemala and Mexico–multiple uses of the Sterile Insect Technique in a successful area wide control program

The Joint Guatemala-Mexico-USA Medfly Program was established in 1977 to prevent the unmitigated spread of Mediterranean fruit fly (Medfly), Ceratitus capitata Wied. (Diptera: Tephritidae), from the areas in Central America it gradually invaded since 1955, into the Medfly-free areas of Mexico, Belize, Guatemala and the United States. Primarily operating throughout Chiapas, the southern-most state of Mexico, and the northern parts of Guatemala, the Program has been successful in maintaining a functional barrier for 30 years. Even though the Program integrates a variety of control tactics, the Sterile Insect Technique (SIT) is used as the primary tool for the mitigation of the target pest. The Program’s technical managers in Guatemala have developed new approaches centred on the use of sterilized male adult fly releases using the temperature sensitive lethal (tsl) VIENNA-7 Medfly strain first developed by the International Atomic Energy Agency (IAEA) in Vienna, Austria. In order to maintain an effective barrier, SIT releases are used in the Medfly Program to accomplish three distinct operational goals. These include preventative releases in areas considered to be Medfly-free, suppression work in infested areas and actual eradication in low prevalence areas. When sterile male releases are carefully combined with such activities as aerial and ground Spinosad bait spray applications, parasitoid releases and fruit stripping, the short term effect is the significant suppression of pest populations. The area-wide integration of these same activities, if systematically continued uninterrupted for a sufficient amount of time, will eventually result in the complete eradication of outbreaks along the barrier.