APHIS Factsheet

Plant Protection and Quarantine April 2015

The Mediterranean 

Fruit Fly

 The Mediterranean fruit fly (Ceratitis capitata), 

commonly called medfly, or Moscamed in Spanish, is 

one of the world’s most destructive agricultural pests. 

The female medfly attacks ripening fruit, piercing the 

soft skin and laying eggs in the puncture. The eggs 

hatch into larvae (maggots) that feed inside the fruit 

pulp and make the fruit inedible. The medfly’s host 

range includes more than 300 plant species.

Potential Damage

In the United States, the medfly could attack 

apples, apricots, avocados, citrus, cherries, figs, 

grapes, guavas, kumquats, loquats, mangoes, 

nectarines, papayas, peaches, pears, peppers, 

persimmons, plums, tomatoes, and several types 

of nuts, among many other crops.

If the medfly were to become established here, 

consumer prices would go up and produce would 

become less available. Also, pesticide use would 

increase in backyard gardens and commercial farms.

The estimated annual market value of U.S. commodities that could host exotic fruit flies is more than 

$7.2 billion. That dollar figure is the sum of potential 

damage to our Nation’s economy from export sanctions, lost markets, treatment costs, reduced crop 

yields, plant deformities, and premature fruit drop.

Distribution

The medfly is found in most tropical and subtropical areas of the world. Originating in Africa, the 

pest has since spread throughout the Mediterranean, 

Southern Europe, the Middle East, Western 

Australia, South and Central America, and Hawaii. 

Most recently, it was also detected in the Caribbean. 

In general, the medfly’s presence in the United 

States has been limited. The only State with an 

established medfly population is Hawaii, where it has 

been present since 1910. No eradication program 

is underway in Hawaii. On the U.S. mainland, the 

first infestations occurred in Florida in 1929. Several 

infestations have been found and eradicated on the 

mainland since then. These efforts have kept the 

medfly from becoming established in the mainland 

United States. 

In 2015, the medfly was discovered in Punta 

Cana, Dominican Republic, and Cabo Rojo in Puerto 

Rico. The Caribbean had previously been free of 

this pest. In 2014, the medfly was also detected in 

Riverside County, CA. These detections are currently 

being eradicated.

Appearance and Life Cycle

The adult medfly is slightly smaller than a common housefly and is very colorful. It has dark blue 

eyes; a shiny, black thorax (back); and a yellowish 

abdomen with silvery crossbands. Its wings, normally 

drooping, display a blotchy pattern with yellow, brown, 

and black spots and bands.

 The life cycle of the medfly has five phases:

1) The adult female deposits eggs under the 

 fruit’s skin.

2) The eggs hatch and produce wormlike 

 larvae (maggots).

3) The larvae feed on the fruit’s pulp before 

 dropping to the ground, where the larvae 

 burrow into the soil.

4) The larvae transform into pupae in the soil.

5) The pupae mature into adults (flies) and 

 emerge from the soil.

 Under tropical summer weather conditions, the 

medfly completes its life cycle in 21 to 30 days.

The Exotic Fruit Fly Strategic Plan

The U.S. Department of Agriculture (USDA) has 

a robust plan in place to protect American agriculture 

from medfly and other exotic fruit fly pests. The 

2011–2015 Exotic Fruit Fly Strategic Plan brings 

together all exotic fruit fly programs, including 

Mediterranean, Mexican, and Oriental fruit flies. The 

plan combines surveillance activities, control programs, 

and regulatory actions. It offers an integrated, multifaceted approach for State and Federal officials and 

partnering foreign governments to fight against fruit fly 

pests effectively. 

The main goals of the plan are to:

•	 Prevent individual fruit fly introductions from 

becoming established populations;

•	 Reduce the imminent threat of introduction 

or spread of med- and mexfly from existing 

populations in Central America;

•	 Mitigate the impact of some fruit flies already 

established in portions of the United States;
•	 Encourage the development of exotic fruit fly 

detection and management programs in 

the Caribbean Basin and Central America to 

act as an early warning system and further 

reduce the risk of introduction in the United 

States; and

•	 Provide technical support for activities to 

reduce fruit fly populations worldwide and 

further decrease the risk of fruit fly entry in 

our country.

Eradication Efforts

When fertile medfly adults or larvae are detected 

in the continental United States, USDA works closely 

with State agriculture officials to eradicate the infestation as quickly as possible. We treat the area around 

the detection with a mixture of insecticide and bait to 

reduce or eliminate the adult stage of the insect. We 

also place traps in the field to determine the extent 

of the infestation. After completing the bait-treatment 

schedule, we release sterile medflies in and around 

the treatment zone to interrupt the breeding cycle. 

When enough time has elapsed for three generations 

of the insect to have matured—and if the survey has 

not identified any more medflies—we declare the area 

to be, once again, free of the pest.

Survey Programs

 USDA also works with State departments of 

agriculture to maintain trapping programs in high-risk 

areas of States susceptible to medfly establishment. 

When one or more wild medflies are collected in an 

area, USDA and State officials immediately begin a 

delimiting survey. Using the detection site as the focal 

point, field crews place extra traps to find out if an 

infestation exists and to locate and define the limits of 

the infested area.

Preventing Medfly Spread

 If an infestation exists, USDA and the States 

impose quarantine regulations to help keep the pest 

from spreading through the movement of infested 

fruit—via trade shipments or by people unknowingly 

carrying infested fruit from one place to another. 

Federal quarantine laws regulate the interstate movement of any products that may harbor the fly. State 

regulations control the movement of these products 

going to uninfested areas within a State. 

 Regulated items include all medfly-host fruits and 

vegetables present in the quarantine area. Open-air 

fruit and vegetable stands must have protective covers for the produce to prevent infestation. Commercial 

and homegrown produce may not be moved without 

inspection, treatment, and certification. 

Control Measures

Three kinds of treatment are used alone or in combination to eradicate the medfly:

•	 Aerial and ground foliar bait spray application. 

The spray contains minimal amounts of a U.S. 

Environmental Protection Agency-approved (EPA) 

insecticide and a protein/sugar bait that attracts 

the flies. Aerial sprays are used by commodity 

producers in rural growing areas.

•	 Sterile insect technique (SIT). In this technique, 

medflies are reared in large quantities, sterilized 

with a small amount of irradiation, and released 

from airplanes or by ground into host areas where 

they mate with wild medflies. These matings do not 

produce offspring. Eventually the wild population 

is eliminated through attrition. SIT is most effective 

against low-level medfly populations where it is 

possible to achieve a high proportion of sterile to 

wild flies. Also, before using SIT, insecticide bait 

spray must be applied in the area to lower the 

density of local medfly populations.

•	 Insecticide application to soil under host trees. 

This treatment is used only when larvae or mated 

female medflies are detected. These products will 

kill some larvae as they enter the soil to pupate 

and most of the adults as they later emerge. The 

preferred and most popular eradication strategy, 

however, is an integrated approach combining 

some of these treatments or all three, with 

emphasis on using SIT.

The Medfly in Mexico and Guatemala

 In 1977, the Governments of the United States, 

Mexico, and Guatemala began a cooperative effort 

known as the Moscamed Program to eradicate 

the medfly from Mexico and maintain a barrier in 

Guatemala to halt the medfly’s northern spread. This 

program is designed to suppress and eradicate medfly 

populations and reduce the risk of introduction into the 

United States from Central America. 

 The Moscamed Program operates two facilities that produce sterile medflies—one in Metapa de 

Dominguez, Mexico, and one in El Pino, Guatemala. 

 Mexico has been free of medfly since 1982, 

except for the southernmost State of Chiapas, adjacent to Guatemala where occasional outbreaks occur. 

Sometimes, people transport the pest north, causing 

outbreaks in border towns. The USDA, Mexico, and 

Guatemala have a Fruit Fly Commission that works 

toward the continued control and eradication of medfly 

in vulnerable areas of southern Mexico and Belize and 

in medfly-free areas of Guatemala. 
Protecting U.S. Agriculture

Many of the insects, weeds, and plant diseases that 

attack U.S. crops don’t exist naturally in our country. 

USDA has agricultural quarantine laws in place to help 

keep exotic plant pests and diseases out of our country 

and to control domestic pests and diseases we already 

have here. 

 Travelers returning to the continental United States 

from Hawaii or a foreign country are prohibited from 

bringing into the country fresh fruits, meats, plants, 

birds, and plant and animal products that may harbor 

pests or diseases.

Learn More

 If you have questions about the medfly or associated 

Federal restrictions, call our staff at (919) 855-7426. This is 

the central office for the Plant Protection and Quarantine 

(PPQ) Fruit Fly Policy Management unit of USDA’s Animal 

and Plant Health Inspection Service (APHIS). 

 You may also call your local Extension office 

(www.nifa.usda.gov/Extension), State Plant Regulatory 

Official (www.nationalplantboard.org/member), or your 

nearest USDA-APHIS office (www.aphis.usda.gov/

planthealth/sphd). 

 The USDA-APHIS Web site at www.aphis.usda.gov 

offers up-to-date information on various agricultural 

pests and diseases and other related topics. For general 

information about the medfly, visit www.HungryPests.com.

United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture

USDA is an equal opportunity provider and employer.

APHIS 81-35-028