Beyond Pesky Flies

On June 2, county officials announced a quarantine on areas of Mira Mesa after finding four adult Mediterranean fruit flies and 14 larvae in the neighborhood.

“They were all found in residential yards,” says county agricultural commissioner Bob Atkins.

One of the adult medflies (a mated female) was discovered in a trap in a loquat tree at a residence on Flanders Drive in the Miramar area. The other three (one of which was a mated female) were found in a trap in a calamondin orange tree on a street named Embry Point. Fourteen medfly larvae were discovered on May 31 in the fruit of a calamondin orange tree at a residence on Bacadi Drive.

Mated female fruit flies are especially destructive, as they can lay eggs at any time during their lifespan. The genetic type of the flies, known as “AAAB,” was consistent with the previous medfly discoveries earlier this year in the El Cajon area.

“The AAAB type is consistent with populations that are distributed in Central America and most of the previously recorded detections in Southern California,” says Atkins, noting that the type has also been found in Africa and the Mediterranean region.

How did the flies end up in Mira Mesa?

“Because the eggs and young maggots are invisibly located within the fruit, the people who ship or carry fruit to friends and family don’t realize the damage they are doing,” says Atkins. “They think the government is trying to protect the big agri-business producers from competition, rather than protecting all growers -– from the backyard to the large orchard –- from new pests.”

Medflies are known to infest up to 260 species of fruits and vegetables. Mira Mesa is a neighborhood that is abundant in fruit trees. The discovery of the flies and larvae has prompted the County and the California Department of Food and Agriculture to conduct extensive trapping in the area. In addition, sterile medflies have been released into Mira Mesa to mate with the female flies. The trees and fruit from the affected and surrounding areas are also being treated.