|Mexican fruit fly, Anastrepha ludens (Loew). |
Image by by Hartmut Wisch. Iowa State University: BugGuide
In what was an inevitable outcome of massive international trade, a male Mexican fruit fly, Anastrepha ludens (Loew) was intercepted in Maryland for the first time at the Baltimore-Washington International Airport in September. The United States was once insulated from novel species accidental introductions by cast oceans and particular predictable long term weather patterns. Unless intentionally introduced and cultivated until established, species did not simply wander in. Today, the size and scope of international trade provides the perfect pathway for repeated unintentional introductions of non-indigenous species a few of which get their green cards quickly and begin to proliferate causing harm to commerce and to ecosystems. We call these few invasive species.
The skill and proficiency of USDA APHIS and ARS scientists and professionals collaborating with U.S. Customs and Border Protection work to prevent the introduction of unwanted, unknown and potentially harmful organisms. Finding one fruit fly at one airport should give us pause to consider the likelihood that a Mrs. Anastrepha managed to escape detection.
The Mexican fruit fly is at home in Mexico and much of Central America as far south as Costa Rica. It has migrated into the cultivated citrus sections of the west coast of Mexico and northward toward Texas, Arizona and California.
In January 2012, the USDA-APHIS announced that the Mexican fruit fly was eradicated from the last county in Texas in which it had been present. However only three months later on March 9, 2012, the Animal and Plant Health Inspection Service (APHIS) established a Mexican fruit fly (Mexfly) quarantine area in the San Benito area of Cameron County, Texas applying restrictions on the interstate movement of regulated articles from this area in order to prevent the spread of Mexfly to non-infested areas of the United States.
The really big question is why you care. Out visitor reduces the amount of all varieties of citrus that you can buy, lemons and sour limes excepted. The Mexican fruit fly loves grapefruit most of all but is comfortable competing with you for oranges, white sapote and mango. Closer to home in Maryland are pears, peaches and apples are eagerly sought after by our new acquaintance. And if this were not enough, A. ludens has been shown, according to the University of Florida's Featured Creatures website, to sample avocado, cherimoya, custard apple, mamey, pomegranate, quince, rose apple, yellow chapote, cacti, figs, bananas, tomatoes, peppers, squash and beans.
Invasive species do matter, and they do cost. More than a decade ago invasive species were estimated to impact the United States to the tune of 130 billion dollars a year. Do you think this cost has gone down, or given the reduction in the scope and funding of the federal government and the increase in global trade, gone down?
 USDA APHIS handout to the Maryland Invasive Species Council November 2012.
 Featured Creatures provides in-depth profiles of insects, nematodes, arachnids and other organisms. The site is a cooperative venture of the University of Florida's Entomology and Nematology Department and the Florida Department of Agriculture and Consumer Services' Division of Plant Industry. [accessed November 23, 2012]http://entnemdept.ufl.edu/creatures/fruit/tropical/mexican_fruit_fly.htm
 From February 27 to March 7, 2012, seven unmated and one mated adult female Mexflies were detected in grapefruit and orange trees located in a commercial grove in the San Benito area of Cameron County, Texas. APHIS, in cooperation with the Texas Department of Agriculture (TDA), is responding to the detection. .. The establishment of this quarantine area is posted on the following APHIS website, which contains a description of all the current Federal fruit fly quarantine areas: http://www.aphis.usda.gov/plant_health/plant_pest_info/fruit_flies/index.shtml [accessed November 23, 2012] http://www.pestalert.org/oprDetail.cfm?oprID=515
 Economic and environmental threats of alien plant, animal, and microbe invasions (2001)
David Pimentel, S. McNair, J. Janecka, J. Wightman, C. Simmonds, C. O’Connell, E. Wong, L. Russel, J. Zern, T. Aquino, T. Tsomondo [ACCESSED nOVEMBER 23, 2012] http://www.invasivespeciesinfo.gov/economic/us.shtml#.UK9-O4c8CSo