 The med fly is one of the world's most destructive fruit pests. Female flies cause damage by laying their eggs in fruit and vegetables. The sterile insect technique, or SIT for short, is an effective way to combat these pests. At mass rearing facilities like this one in Guatemala, flies are produced and sterilized with radiation. The colonies of flies live and mate in cages where the females lay their eggs. Eggs are collected and the female ones are separated from the males. A thermal treatment is used to eliminate the female eggs at 34 degrees. The male eggs are placed in food trays where they hatch into larvae. Their food is a specially prepared mixture that mimics real fruit. Then they jump out to begin the next phase of their life cycle. They're left in a dark room where they evolve into pupae. These are collected and exposed to a mixture of fluorescent dye which marks them for future identification. Next they're prepared for the irradiator. The male pupae are sterilized with a radiation source. This damages their sperm and makes them infertile. From here they're transported to packing and release centers where they're held in preparation for the transition into adult flies. The flies are then collected and chilled to immobilize them before being placed into boxes for aerial release. In Guatemala, 37 million flies are loaded onto the plane for each release. The sterile flies are released over the med fly infested areas. Here they mate with the wild female flies but their mating produces no offspring. An increasing number of sterile males in traps compared to the number of wild ones is an indication that the technique is working. An ultraviolet light is used to identify the fluorescent dye which was added at the rearing center. This distinguishes the captured sterile flies from the wild flies. Pest-free fruit is also a good indication that SIT is effective. When integrated with other pest control methods and implemented continuously over a set period of time SIT is an effective way to suppress or even eradicate med flies over a wide area. The IAA together with the FAO and through its technical cooperation program supports the use of area-wide SIT to control the pest. With the med fly under control, farmers can produce more and healthier fruit and vegetables. Export markets can be expanded and opened and local and national economies are improved.