Oriental fruit fly invasion prompts quarantine for slew of South Bay cities, officials say

SAN FRANCISCO (KGO) -- A slew of South Bay cities are under quarantine following an infestation of the Oriental fruit fly, according to the California Department of Food and Agriculture.

It's a multi-billion dollar pesky problem that's posing an economic and environmental threat to Santa Clara County.

According to the state, eight flies have been detected in Santa Clara and Sunnyvale. This prompted a widespread quarantine on 112 square miles across the county -- including Santa Clara, portions of Cupertino, Milpitas, San Jose and Sunnyvale.

The quarantine prohibits any shipment of fruits and vegetables out of these areas until next June.

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"Now that we have an established infestation, we're going to be on lockdown of any movement of fruits or vegetables so we don't spread the fly," said Joseph Deviney, Santa Clara County's agricultural commissioner. "It's a serious threat."

Deviney says the Oriental fruit fly infestation has doubled statewide in recent years.

"The female deposits, usually ten to 100 eggs and per fruit. So when you go to pick your fruit off your tree, you open it up, it'll have ten to 100 maggots," said Deviney. "A single female fly can lay 1,500 eggs easy."

To prevent the spread, the county asks residents in the quarantined areas not to move homegrown fruits and vegetables from their property. Instead, the county suggests eating or processing the food on the property where it was grown -- whether that's in the blender or down the garbage disposal. You can also double bag the food and dispose of it in regular trash bins not in green waste bins.

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The California Dept. of Food and Agriculture says it will treat the area where the flies were trapped using an organic pesticide administered through an application device. This process is expected to continue through March of next year.

"So we don't go into backyards, nothing from helicopters, it's just a splat all through the neighborhoods in this area," Deviney said.

A pesky problem that's not cheap. According to the state, the value of California crops threatened by the fruit fly in 2020 was $19.3 billion.

"Our exports will suffer," Deviney said. "Farmers are trying to get away from the use of pesticides, but now they will have to spray even more to prevent their fruit from being infested. So it's definitely going to affect everybody from the homeowner to the entire state's economy."

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"Really devastating for many of the growers, especially the small growers...it pretty much destroys any possibility for them marketing their produce for that year," said James Carey, a professor of entomology at UC Davis, who's been studying fruit fly invasions across the state since 1980.

According to Carey, outbreaks of this fruit fly have occurred in California annually for the past 50 years. He says he's tracked infestations across a total of 254 cities, from San Diego to Redding.

"Nowhere else in the U.S. or the world does this occur. This pest is established in the state, including throughout the Bay Area," Carey said. "Although this is only the third outbreak year for the city of Santa Clara, there have been 15 outbreak years for San Jose."

Carey added since 1983, outbreaks have occurred in the cities of Cupertino, Gilroy, Los Altos, Los Altos Hills, Los Gatos, Milpitas, Morgan Hill, Mountain View, Palo Alto, San Jose, Santa Clara, Saratoga and Sunnyvale.

According to the county, the most common ways for the Oriental fruit fly to enter the state involves residents accidentally bringing in prohibited fruits and vegetables back from their travels or due to receiving packages of prohibited homegrown produce through the mail.

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