Mediterranean Fruit Fly

The Mediterranean fruit fly, commonly known as the medfly, is a tropical insect that infests over 250 species of plants, including many fruits, nuts and vegetables. Because of its rapid development and wide host range, the medfly is one of the most serious agricultural problems in warm parts of the world. The adult is a little smaller than a housefly, with droopwings that are banded with yellow, brown, and black.

The spread of the medfly: The medfly is a native of tropical West Africa. Since the mid-1800s, it has been spreading to many of the warmer parts of the world, including Hawaii, Southern Europe, and Central and South America. It has been found in the United States off and on since 1929, when it was first discovered in Central Florida. Since that time, outbreaks in Florida, Texas, and Southern California have been eradicated. The medfly is usually transported into the country as a larva in infested fruit. Most new infestations are the result o travelers bringing home infested fruit and vegetables.

The life circle: Egg laying begins in the spring after the weather has remained warm (over 75°F) for a week. Male and female flies congregate on fruit, where they mate. The female then finds a fruit that is beginning to ripen. She drills a hole through the skin with her ovipositor (egg-laying organ) and inserts up to 10 white eggs in a cavity. One female can produce up to 1000 eggs during her lifetime. The larvae feed on the ripening fruit, which may rot on the inside. The fruit may appear normal, but fall off the plant prematurely. The mature larvae bore an exit hole and drop to the ground. They pupate in the soil or under objects on the ground. The adults ffed on honeydew that is excreted by aphids, mealybugs, and scale insects. Medflies can fly over a mile, but usually remain near the plants in which they developed as larvae. There may be as many as 14 generations during the growing season.`