In this age of jet transportation, this “beautiful” pest can travel from one part of the world to some distant place in a matter of hours. Because the fruit flies are fairly small creatures about the size of large aphids, they are almost impossible to detect with just a glance. They originate in sub-Saharan Africa, and as with moths, it is the larvae that cause the real damage.

Photo Credit: Scott Bauer

A male Med fly is shown resting on a leaf.

The Med fly may be a major pest of citrus, but it often is a more serious pest of some deciduous fruits, such as peaches, pears, and apples. The Med fly attacks more than 260 different fruits, flowers, vegetables, and nuts and is one of the most destructive pests known to man. The Med fly causes damage by laying its eggs just beneath the skin of ripening fruit. The larvae feed upon the pulp of the fruit, sometimes tunneling through it and eventually reducing the whole to a juicy inedible mass.

The Med fly became established in Hawaii in 1910 and is still a major problem today. The Department of Agriculture’s (USDA) Pacific Basin Agricultural Research Center (PBARC), located in Hilo, Hawaii with research sites at Manoa and Aiea, Oahu and at Kapaa, Kauai, is currently working on new ways to find natural enemies of the Med fly. It is also raising millions of sterile Med flies for Med fly control in Southern California.

Infestation
The first U.S. mainland infestation occurred in Florida in 1929. Several infestations have occurred on the mainland since then. The latest sighting of this brightly colored adult fly and its larvae in September, 2004 in Tijuana, Mexico, has led to the implementation of emergency response measures to protect U.S. agricultural resources from this destructive and costly pest. In California, Med fly battles have cost taxpayers nearly $500 million during the past 25 years. A 1997 attack on Med fly in Florida's Tampa Bay region lasted nine months and cost $25 million.

In 1993, APHIS estimated that annual losses attributable to the Med fly in the continental United States would be about $1.5 billion annually if this exotic pest were to become established. These losses would come in the form of export sanctions, lost markets, treatment costs, reduced crop yields, deformities, and premature fruit drop.

Photo Credit: Scott Bauer

A female Med fly lays eggs into the soft outer layers of a ripe coffee berry.

Because this pest is so potentially injurious to crops, year-round trapping is maintained as an early warning system in Florida, Texas, Arizona, California, and in Northern Mexico and Baja California. The instant detection is made, eradication and regulatory restrictions are set in place to prevent the fly from moving into other areas.

Adding to the problem of detection is that the pest is not detectable to the naked eye. Fruit must be cut to determine whether larvae are present.

Emergency interim measures in effect until further notice
U.S. Customs and Border Protection (CBP) and the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA/APHIS) have implemented emergency interim measures at all land border ports in California, Arizona, New Mexico and El Paso, Tex.

All commercial agricultural shipments from Mexico entering land border ports in California, Arizona, New Mexico and El Paso, Tex. with commodities on the Med fly host list require a Mexican phytosanitary certificate. In addition, the cargo must come with a special declaration stating that the cargo originated outside the Tijuana, Baja California area and was not packed in or transported through that area.

All materials carried by pedestrians and vehicles entering from Mexico at the ports of entry at Otay Mesa, San Ysidro, and Tecate on the Med fly host list will be confiscated. CBP agriculture specialists will cut the seized fruit fly host material and note the source and origin of any pests that are found.

CBP airport and seaport operations handled by the port of San Diego, Calif., are focusing on small yachts and private aircraft coming from the Tijuana area.

Med fly alert signs have been posted at pedestrian and vehicle crossings to alert the public to the current outbreak. CBP officials are also working with local, state, and Federal agencies and with industry stakeholders to coordinate efforts to stop the spread of this dangerous and costly pest. CBP officers and Border Patrol agents will be provided color posters of Med fly host fruit to help identify host material.

Approximately two weeks before the crackdown, 448 Quarantine Material Interceptions (QMIs) were made at the land border port of Calexico, Calif. Two weeks after the crackdown, 2,224 QMIs were made. At the port of Otay Mesa, 26 trucks with Med fly host material that didn’t meet the phytosanitary certificate requirements were rejected in the first two weeks of the alert.

Border Patrol’s efforts
CBP Border Patrol agents at locations within the San Diego and El Centro sectors in California have started a unique program to increase inspections for Med flies between the ports of entry. For the duration of the emergency response efforts, Border Patrol agents in these areas will confiscate any produce found on individuals who are stopped at checkpoints and other locations. The seized produce will be placed in special bins that have been donated by the USDA, and transported several times a week to the nearest port of entry for examination by CBP agriculture specialists.

Unfortunately, the threat of an infestation of the Mediterranean fruit fly seems to be here to stay. But the efforts of CBP agriculture specialists and Border Patrol agents are going to make sure that it becomes harder than ever for this beautiful little pest to enter and make its home permanently here in the United States.