In the Wake of the Fruit Fly Invasion, CDFA Assesses Crisis Response

Brian GermanIndustry, Pest Update

Secretary Karen Ross of the California Department of Food and Agriculture (CDFA) is reflecting on the coordinated response to the fruit fly invasion with hopes to lift quarantines soon. 

In the summer of 2023, invasions came as an alarm to agriculturists as four species of exotic fruit flies infested regions in Southern and Northern California. The pests lay eggs in fruit, causing produce to rot, and had the potential to infest over 400 types of crops in the state unless action was taken immediately. Eradication techniques risked being disruptive to local crop production and threatened economic stability. 

Fruit Fly Invasion

“It was a very frightening situation and still is,” Secretary Ross said, “It was all hands on deck: county, state, and federal governments working very closely together to be a seamless operation.” 

The various eradication methods of Oriental fruit fly (the largest of all fruit fly outbreaks), Mediterranean fruit fly, Queensland fruit fly, and Tau fruit fly included local quarantines across California, crop stripping to disrupt fruit fly life cycles, foliar sprays, and removal of infected trees.  

Ross said that while the Mediterranean fruit fly is a traditional pest of the Los Angeles Basin, the Tau and Queensland fruit flies “are frightening because those are species that have not been found in this hemisphere.” 

To further mitigate the spread of the pests, CDFA partnered with county governments, “engaging with the public and making sure that we had outreach in all the languages we needed, that people knew what was going on,” Ross said. “The federal and state government made investments in the current fiscal year to make sure we could keep the [eradication] programs going.”  

Some of the eradication methods are outdated, Ross explained. “We have allocated resources on high-risk pathways for us and the counties on the same kinds of information that came out of studies from 30 years ago,” she said. The CDFA hopes to learn from the current exotic fruit fly invasion.  

“There’s something different going on, and we really need to understand that and prepare ourselves as best we can,” said Ross. 

The secretary is hopeful that with continued efforts and resourcefulness, quarantines in Southern California will be reduced soon, “which would be astounding when you looked at the situation we were in,” she said.

As of July 11, the Mediterranean fruit fly quarantine in Los Angeles County extends across 159 square miles from Los Angeles to Redondo Beach. The Oriental fruit fly quarantine is in the southern region of San Bernardino and northern Riverside Counties, extending 554 square miles. The Queensland fruit fly quarantine surrounds 90 square miles between Moorpark and Agoura Hills. The Tau fruit fly quarantine was lifted July 1, but formerly consisted of 110 square miles in the Santa Clarita area. 

More information about invasive fruit flies and ongoing quarantines in California is available at

Contributing Author:
Lauren McEwen
AgNet West Intern