Fruit Flies

The discovery of a wild Mexican fruit fly in Downey has prompted state officials to expand an agricultural quarantine zone from 60 to 100 square miles of Southeast Los Angeles County. An unmated female Mexican fly was found in a trap just a half-mile outside the existing quarantine area in Downey on Feb. 13, bringing the number of flies found since last November to 17.

State agricultural officials have begun the second of four treatments in the north-central portion of the Valley to eradicate the season's first Oriental fruit fly infestation of the season. The county uses a "male annihilation treatment" to combat the flies, said Bob Donley, deputy director of the Environmental Protection Bureau of the county Agricultural Commissioner's Department. The spraying is done from trucks.

Fruit flies have the rudiments of consciousness, according to a study published online in the journal Nature Neuroscience. Bruno van Swinderen and Ralph Greenspan of the Neurosciences Institute in San Diego presented flies with various images. The flies responded with a characteristic burst of brain activity.

The federal government on Friday expanded the size of an agricultural quarantine area in Los Angeles County by 70 square miles because of the discovery of more Oriental fruit flies, officials said. The quarantine restricts shipment of fruits and vegetables. Oriental fruit flies can damage 200 types of citrus fruits, vegetables, nuts and berries but do not pose the same danger as the Mediterranean fruit fly.

Two Oriental fruit flies have been trapped, one in Azusa and the other in Glendora, prompting officials to order ground spraying of a pesticide on utility poles and trees in a 13-square-mile area. One fly was found Tuesday in the 700 block of Gladstone Street in Glendora, and the other was discovered Wednesday in the 18000 block of Bellefont Drive in Azusa, the county Department of Agriculture reported Friday.

For the first time, Oriental fruit flies have been discovered in Riverside County, prompting an eradication campaign that will cover about nine square miles around the community of Beaumont. Unlike the eradication effort against the Mediterranean fruit fly, the Oriental fruit fly campaign will not require malathion spraying. Oriental fruit flies are destroyed using the virtually unnoticeable treatment of spraying pesticide-laced bait on utility poles and trees.

Fruit flies that are stressed by shock or shaking emit a chemical odor that warns away other flies, researchers from Caltech reported in this week's issue of the journal Nature. One of the main ingredients of the repellent is carbon dioxide. That surprised researchers because carbon dioxide is one of the primary chemicals that attract mosquitoes to humans.

Five male peach fruit flies, usually found in India and Southeast Asia, have been found in traps in residential back yards, state agriculture officials said Friday. Three of the insects were found in a single trap in a pineapple guava tree and the others were found in traps in avocado and orange trees, located on nearby streets.

Mexican and U.S. officials have controlled an outbreak of Mediterranean fruit flies in Tijuana, but they are not yet declaring the pests eradicated. No larvae have been found since Oct. 20, and no adults have been found since Oct. 26, said Nicholas Gutierrez, a U.S. Department of Agriculture official.