Mediterranean Fruit Fly
The Mediterranean Fruitfly or Medfly (Ceratitis capitata) is a very important pest of soft fruit throughout the Mediterranean, Africa, central and southern America and Western Australia. It is not known to be established in the United States, but when it has been detected in Florida and California, each infestation initiates intensive and massive eradication and detection procedures so that the pest did not become established.
Biology
There are as many as six generations per annum in hot countries. In more temperate regions the number is usually 2 to 3 per annum. The fly can move from one crop to another so that it is not necessarily restricted to the seasonality of one crop.
Because of its wide distribution over the world, its ability to tolerate cooler climates better than most other species of tropical fruit flies, and its wide range of hosts, it is ranked first among economically important fruit fly species. Larvae feed and develop on many deciduous, subtropical, and tropical fruits and some vegetables. Although it may be a major pest of citrus, often it is a more serious pest of some deciduous fruits, such as peach, pear, and apple. The larvae feed upon the pulp of host fruits, sometimes tunnelling through it and eventually reducing the whole to a juicy inedible mass. In some of the Mediterranean countries, only the earlier varieties of citrus are grown, because the flies develop so rapidly that late season fruits are too heavily infested to be marketable. Some areas have had almost 100% infestation in stone fruits. Harvesting before complete maturity also is practiced in Mediterranean areas generally infested with this fruit fly.
In this age of jet transportation, the "medfly" can be transported from one part of the world to some distant place in a matter of hours, which greatly complicates efforts to contain it within its present distribution. Once it is established, eradication efforts may be extremely difficult and expensive. In addition to reduction of crop yield, infested areas have the additional expense of control measures and costly sorting processes for both fresh and processed fruit and vegetables.
Medfly adults are slightly smaller than a house fly and have picture wings typical of fruit flies. The eggs are very slender, curved, 1 mm long, smooth and shiny white. Larvae are white with a typical fruit fly larval shape (cylindrical maggot-shape and somewhat recurved ventrally), usually 7 to 9 mm in length. Adults are 3.5 to 5 mm in size, yellowish with a brown tinge, especially on abdomen, legs, and some markings on wings. The eyes are reddish purple. Wings, usually held in a drooping position on live flies, are broad and black, brown, and brownish yellow markings.
Complete life cycle is 21 to 30 days. A female medfly will lay 1 - 10 eggs in an egg cavity 1 mm deep and may lay as many as 22 eggs per day (typically 300 eggs during a lifetime). The number of eggs found at any time in the reproductive organs is no indication of the total number of eggs an individual female is capable of depositing, as new eggs are being formed continually throughout her adult life.
Eggs are deposited under the skin of fruit which is just beginning to ripen, often in an area where some break in the skin already has occurred. Several females may use the same deposition hole with 75 or more eggs clustered in one spot. When the eggs hatch, the larvae promptly begin eating, and at first tunnels are formed, but may keep close together in feeding until nearly full grown. Fruit in a hard or semiripe condition is better for oviposition than fully ripened fruit.
Females will not oviposit when temperatures drop below 16°C (60.8°F) except when exposed to sunlight for several hours. Development in egg, larval, and pupal stages stops at (10°C) (50°F). Medfly overwinter as pupae. During warm weather eggs hatch in 1.5 to three days. The duration of the egg stage is considerably increased by lower temperatures.
Larvae pass through three instars. The kind and condition of the fruit often influence the length of the larval stage. In citrus fruits, especially limes and lemons, it appears to be longer. Larvae leave the fruit in largest numbers at or just after daybreak and pupate in the soil or whatever is available.
Minimum duration of the pupal stage is six to 13 days. Adults emerge in largest numbers early in the morning during warm weather and emerge more sporadically during cool weather. They can fly short distances, but winds may carry them a mile or more away. Mating may occur at any time throughout the day. Newly emerged adults are not sexually mature. Males often show sexual activity four days after emergence, and copulation has been observed five days after emergence. Both sexes are sexually active throughout the day. Most females are ready to mate from six to eight days after eclosion. Oviposition may take place as early as four to five days (but more typically 10 days) after emergence during very warm weather.
Adults die within four days if they cannot obtain food. Usually about 50% of the flies die during the first two months after emergence. The Mediterranean fruit fly attacks more than 260 different fruits, flowers, vegetables, and nuts. Thin-skinned, ripe succulent fruits are preferred. Host preferences vary in different regions.
Products
Crops
Documents