About the Mediterranean Fruit Fly (Medfly)
The Mediterranean fruit fly (Medfly) originated in Africa and is found in most tropical and subtropical areas of the world. The Medfly has spread throughout the Mediterranean region, southern Europe, the Middle East, Western Australia, South and Central America and Hawaii. The first of numerous U.S. mainland infestations occurred in Florida in 1929.
The Medfly has the widest host range of any pest fruit fly and is considered the most important agricultural pest in the world. It has been recorded infesting a wide range of commercial and garden fruits, nuts and vegetables, including apple, avocado, bell pepper, citrus, melon, peach, plum and tomato.
The United States Department of Agriculture (USDA) and the California Department of Food and Agriculture (CDFA) have imposed an agricultural quarantine in the Escondido, Fallbrook and Imperial Beach areas of San Diego County, as well as the Santa Monica area of Los Angeles County, following the detection of multiple Medflies.
What Does the Medfly Look Like?
The Medfly is smaller than a house fly. It has a blackish thorax marked with silver, a tan abdomen with darker stripes and clear wings with light brown bands and gray flecks. The eggs are white, very small and elongated. Larvae are legless and white. The pupa is contained inside an elongated oval, shiny brown, hard puparium.
What is the Medfly’s Life Cycle?
An adult female Medfly will pierce the skin of fruits and vegetables to lay from one to 10 eggs inside the fruit. The eggs hatch and develop into larvae, which feed on the fruit pulp. Decaying, infested fruit usually falls to the ground where the larvae will typically leave the fruit and burrow into the ground to pupate. Adult Medflies emerge from the ground and can live up to two months.
What Kind of Damage Can the Medfly Cause?
The Medfly is among the most destructive, feared and well-publicized pests in the world. Medfly causes damage by infesting fruit, vegetables and nuts with eggs. As the larvae develop and feeds on the pulp, the fruit decays and falls to the ground, thereby destroying the crop. The Medfly has been recorded infesting more than 300 cultivated and wild fruits, vegetables and nuts. The host list includes:
- Almond with husk
- Apple
- Apricot
- Avocado
- Bell Pepper
- Cherry
- Citrus
- Coffee
- Eggplant
- Fig
- Grape
- Grapefruit
- Kiwi
- Lemon
- Lime
- Mango
- Nectarine
- Olive
- Orange
- Papaya
- Peach
- Pear
- Persimmon
- Plum
- Pomegranate
- Tangerine
- Tomato
- Walnut
What Could That Damage Mean to the Economy?
Tropical fruit flies such as the Medfly are a major threat to California’s agriculture. The damage caused by infestation makes the fruit or vegetable unfit for human consumption. Introduction of the Medfly causes economic losses from destruction and spoiling of the foods, costs associated with implementing control measures and loss of market share due to quarantine of host foods. Many crops in California could be affected by Medfly, and those crops comprise a significant portion of the total agricultural output for the state. A permanent infestation would result in estimated annual losses of $1.3 to $1.8 billion with the loss of 14,000 jobs.
What’s the Mediterranean Fruit Fly Quarantine and Eradication Process?
When Medfly adults or larvae are detected in the continental United States, every effort is made to eradicate the infestation as quickly as possible. The USDA’s Animal and Plant Health Inspection Service, along with State departments of agriculture, maintains trapping programs in high-risk areas of States susceptible to Medfly establishment. If an infestation exists, Federal and State quarantine regulations are imposed to help prevent the spread of the pest.
Three kinds of treatment are used alone or in combination to eradicate the Medfly: bait spray, the sterile insect technique (SIT) and/or directed insecticide applications. Currently, application of insecticide to the soil is used only when larvae are detected. The preferred and most popular eradication strategy is an integrated approach combining all three treatments, with emphasis on the use of SIT.
Where is the Mediterranean Fruit Fly Found in California?
Currently, Medfly quarantine is in effect in the Santa Monica area of Los Angeles County and the Escondido, Fallbrook and Imperial Beach areas of San Diego County. Eradication activities are underway in San Diego County. The most current eradication and quarantine projects can be viewed at: http://www.aphis.usda.gov/
plant_health/plant_pest_info/fruit_flies/quarantine.shtml.
What Can We Do?
Do not bring or mail fresh fruits, vegetables or plants into the U.S. unless agricultural inspectors have cleared them beforehand, as Medfly and other pests can hide in a variety of produce. Never remove fresh produce from your property when your area is under Medfly quarantine.
It’s also important to cooperate with any quarantine restrictions or rules that might be imposed because of a Medfly find in your area, and allow authorized agricultural workers access to your property to inspect fruit and Medfly traps for signs of an infestation.
Resource List [not a comprehensive list]
Mediterranean Fruit Fly Pest Profile
California Department of Food and Agriculture
http://www.cdfa.ca.gov/phpps/PDEP/target_pest_disease_profiles/
mediterranean_ff_profile.html
Fruit Fly Quarantine Information
California Department of Food and Agriculture
http://www.cdfa.ca.gov/phpps/PE/InteriorExclusion/current_ff_erad.html
The Mediterranean Fruit Fly
United States Department of Agriculture, Animal and Plant Health Inspection Service
http://www.aphis.usda.gov/publications/plant_health/content/printable_version/
fs_phmedfly.pdf
Fruit Fly Control Programs
United States Department of Agriculture, Animal and Plant Health Inspection Service
http://www.aphis.usda.gov/plant_health/ea/fruitfly.shtml
