Current Exotic Fruit Fly Quarantines in California

Information : If you have questions about a fruit fly quarantine/eradication, or if you think you have fruits and vegetables infested with fruit fly larvae, call the CDFA Exotic Pest Hotline at 1 (800) 491-1899.

Exotic Fruit Flies

image of the Mexican fruit fly

Exotic fruit flies are of concern to the agriculture industry in California. The larval (maggot) stage of fruit flies such as Mediterranean fruit fly, Mexican fruit fly and oriental fruit fly can damage most of the fruits and vegetables grown in our state. These and other exotic pests have not become established in California due to (1) strict federal exterior and state interior quarantines, (2) a pest detection program, and (3) aggressive eradication programs when an infestation is discovered.

Federal and state quarantines protect against the entry and spread of exotic fruit flies by requiring strict adherence to treatment and inspection procedures for hosts. Smuggled and/or illegally imported fruit is the most common pathway of fruit fly entry into California.

The California Department of Food and Agriculture (CDFA), in concert with most of the County Agricultural Commissioners, deploy and maintain over 63,000 detection traps statewide just for exotic fruit flies.

The fruit flies (family Tephritidae) of most concern are a group of small (1/5" to 1/3") to medium-sized (3/4") flies, with general body coloration that can be in the red, orange, yellow or black ranges. Their wings generally have brownish streaks and may also display scattered dark spots. There are four life stages: adult; egg; larva; pupa (puparium).

The eggs of these flies are slender, white and have an elliptical shape, and are typically laid in batches of 3 to 40, under the skin of the host fruit. The larvae (the maggots in the fruit) are cylindrical in shape, approximately ½" long and creamy white in appearance. The contents of their guts are often visible through their skin, and large numbers can colonize the flesh of individual host fruits. Some species will attack flowers and plant stems as well. The puparium (pupa case) can be colored either dull white, dark brown or black. It is just over an inch long and usually found in the soil from 2" to (rarely) 6" deep.