Discovery of 2 Fruit Flies Nears Limit

Two more sexually mature male Oriental fruit flies have been found in the La Mesa area, the San Diego County agricultural commissioner said Tuesday. This brings the total found in the last month to five.

Should just one more adult fly be found, the county would have to declare that an infestation exists and quarantine produce from the area, Commissioner Kathleen Thuner said.

The Oriental fruit fly, slightly larger than a common house fly and with yellow and black markings on its abdomen, attacks 150 varieties of fruit trees and poses a threat to avocado, citrus and apple orchards. They spoil the ripening of fruit by laying eggs under the fruit’s skin, Thuner said.

“These latest finds confirm we do have something there but we haven’t found any females or larvae in the fruit from the area,” Thuner said. “The warm weather we’ve had lately is good fly weather but we are hoping there will not be a sixth fly.”

Since the latest finds were in orange and grapefruit trees within the 18-square-mile area already under treatment by the county Department of Agriculture, the treatment area will not be expanded, Thuner said. However, the treatment period will be extended.

“The treatment period will be continued . . . for how much longer has not been determined yet,” Thuner said.

The sector being treated with a mixture of molasses-based bait and insecticide includes parts of East San Diego, La Mesa, Lemon Grove, Del Cerro, Allied Gardens, Grantville and Lake Murray. Spraying is at heights of 8 to 10 feet from the ground, so as not to harm pets and children.

After the first find on Aug. 7, county crews increased the number of traps in the La Mesa area. After the Aug. 13 find of a second sexually mature male fly, spraying was begun in East San Diego, La Mesa and Lemon Grove, then expanded by six square miles when a third fly was found five days later.

The next spraying will take place at the end of this week, Thuner said.