Redlands Out From Underneath
Oriental Fruit Fly Quarantine

The California Department of Food and Agriculture has declared an end to the Oriental fruit fly quarantine in the Redlands area following eradication of the invasive species.
On September 27, 2023, the Animal and Plant Health Inspection Service (APHIS) and the California Department of Food and Agriculture imposed a quarantine in San Bernardino and Riverside counties. The quarantine covered 102 square miles of San Bernardino County. Redlands, which is one of the communities in San Bernardino County which has preserved significant portions of historic agricultural property, was at the epicenter of the infestation.
According to APHIS, 1,200 acres of commercial agriculture production of citrus, apples, avocados, peaches and other stone fruits were affected.
The California Department of Food and Agriculture, known by its acronym CDFA worked in coordination with the United States Department of Agriculture (USDA), the Riverside County Agricultural Commissioner, and the San Bernardino County Agricultural Commissioner in arresting the migration of the pest, doing so with the cooperation of the local populace, which complied, for the most part, with orders to refrain from removing fruit from trees and further demands that they not move any produce from their property. If fruit fell from trees, residents were urged to double-bag it and place it in a trash bin rather than green waste bins or other organic refuse designations.
Work crews consisting of a combination of California Department of Food and Agriculture and U.S. Department of Agriculture employees, California Conservation Corps crews, and private contractors specializing in fruit removal then methodically worked their way from one end of the target area to the other, going on to private property to pick up the contaminated, or potentially contaminated, fruit, disposing it into containers from which it was impossible for the flies, larvae or maggots to escape.
California and its fruit industry have been buffeted over the years by several pests, including Mediterranean, Mexican, Tau, melon, peach and guava fruit flies. Oriental fruit flies are most easily distinguished from other flies by their yellow color.
The oriental fruit fly, previously known by the scientific name, Dacus dorsalis and now referred to as Bactrocera dorsalis, is a species of tephritid fruit fly that was endemic to Southeast Asia. It is a major pest species, with a broad host range of cultivated and wild fruits. Having left its native Asia, it is a highly invasive pest that now has a presence in at least 65 countries. It is believed to have invaded Hawaii in 1945 as a contaminant of military material returning from the western Pacific war zone, in particular Taiwan and the Mariana Islands. Fruit imported to the mainland from Hawaii is generally fumigated to prevent the pest from coming her. But fruit brought by travelers, most likely from Hawaii but also from Southeast Asia and other Pacific islands likely allowed the flies to get into California it is believed for the first time in 1960, at which point it began to immediately ravage fruit and vegetables. Eradication efforts by the California Department of Food and Agriculture and the United States Department of Agriculture have been an ongoing struggle since then.
According to the California Department of Food and Agriculture, female flies lay eggs in groups of three to 30 under the skin of host fruits. Larvae tunnel through the host and emerge approximately ten days later. Flies mature into adulthood in ten to twelve days and usually live up to ninety days. Adult flies are strong fliers and can travel as far as thirty miles for sustenance. This aggressive search for food allows the pest to infest a region quickly
The lifting of this quarantine signals the successful completion of a nearly 11-month-long collaborative effort to eradicate four unique invasive fruit fly species (Tau, Queensland, Mediterranean and Oriental) from seven quarantine areas across seven California counties — San Bernardino, Riverside, Los Angeles, Ventura, Santa Clara, Sacramento and Contra Costa.
“This was an unprecedented situation for California to experience this many active invasive fruit fly quarantines at one time,” said Victoria Hornbaker, director of CDFA’s Plant Health and Pest Prevention Services Division. “The response to these destructive invasive species was an enormous effort, and thanks to the cooperation of residents, the agricultural industry, and our government partners at the local and federal levels, we’re incredibly proud to have successfully lifted all active invasive fruit fly quarantines in the state of California.”
Officials said the USDA made critical investments in the response with personnel and funding, and that commitment underscores the importance of ongoing investment in pest exclusion activities.
According to the California Department of Food and Agriculture, “It’s important to remember that the threat of new fruit fly introductions remains. Left unchecked, they can endanger the state’s natural environment, agriculture, and economy. Agricultural officials urge residents to follow simple precautions and stay vigilant for signs of invasive species. To help prevent any future introductions, residents should:
– Cooperate with agricultural officials and allow them access to your garden to place traps, inspect plants, conduct necessary treatments or remove potentially infested produce.
– Buy fruit trees and vegetable plants from licensed California nurseries. Purchasing agricultural goods from uncertified sources can spread invasive pests. Source your plants locally and responsibly. To find a licensed nursery near you, visit CDFA’s Directory of Licensed Nurseries.
– Inspect your garden for signs of invasive fruit flies or maggots and report any findings to CDFA at 1-800-491-1899 or your local county agricultural commissioner’s office.
– When entering the United States from another country, avoid bringing agricultural products — including fruits or vegetables. Help us protect our agricultural and natural resources and California’s unique biodiversity from invasive fruit flies — please Don’t Pack a Pest (www.dontpackapest.com) when traveling or mailing/receiving packages.”
More can be learned about this invasive species and how to protect the county’s fruits and vegetables at CAFruitFly.com, rivcoawm.org or awm.sbcounty.gov.