Various species: Several species of fruit flies are important pests in the United States. These include the apple maggot (Rhagoletis pomonella), Caribbean fruit fly (Anastrepha suspensa), Mexican fruit fly (Anastrepha ludens), walnut husk fly (Rhagoletis completa), and the Mediterranean fruit fly (Ceratitis capitata). The apple maggot (see Apple Maggot) is a pest of apples, plums, cherries, and pears. The Caribbean fruit fly and the Mexican fruit fly spoil the fruit of citrus. The walnut husk fly tunnels into the flesh of walnuts and peaches. The Mediterranean fruit fly, commonly known as the medfly, is potentially one of the most damaging fruit flies, infesting more than 250 species of plants including fruits, vegetables, and nuts.
The medfly: The Mediterranean fruit fly 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. Like other fruit flies, the medly is usually transported as a larva in infested fruit. Many new infestations are the result of travelers bringing home infested fruit and vegetables.
Because it is not possible to eradicate the larvae of fruit flies once they have infested the fruit, most control measures involve prevention. To avoid infestations, harvest fruit as soon as it matures, and pick up and dispose of fruit that falls from the tree.
Quarantine laws: The spread of most fruit flies is controlled by quarantine laws. They are constantly monitored by detection traps operated by state and federal departments of agriculture. Fruit shipped from areas with fruit fly infestations must be fumigated or otherwise treated. Travelers are prohibited from bringing fruits and vegetables into the United States; many states also have restrictions. Despite these precautions, the insects sometimes gain entry to new areas. Because of its wide range of host plants, the medfly is especially threatening. Late spring to fall is the most likely time to detect the medfly. If you live in an infested area or an area where infestations have occurred, you should learn to identify the medfly and notify the local County Extension Agent (see County Extension Agents) if you suspect an outbreak in your neighborhood.
