Watch CBS News

Fruit quarantine in Contra Costa, Santa Clara counties due to fruit fly could affect 2024 production

Oriental Fruit Fly found in parts of Contra Costa County could affect 2024 production, AG commission
Oriental Fruit Fly found in parts of Contra Costa County could affect 2024 production, AG commission 04:07

Agriculture officials are scrambling to deal with a dangerous pest after a large number of Oriental Fruit Flies were found in Brentwood.

Now, 99 square miles in Contra Costa County and 112 square miles in Santa Clara County have been quarantined from transport of fruit out of the area.  And the public has a role to play as well.

It was two weeks ago that AG officials first found an Oriental Fruit Fly in a trap in a Brentwood neighborhood.

"Over the weekend, we didn't find anything else, so we were thinking we were doing pretty good, didn't find them," said Contra Costa County AG Commissioner Matt Slattengren.  "And then, just a couple days in a row we found a whole bunch more flies.  So, that got us quite worried."

Now, the State has imposed a quarantine area of more than 200 square miles in Contra Costa and Santa Clara Counties. The problem for Brentwood is that the infected area is less than two miles from the farm fields that make the region so popular during U-pick harvest season.

Fruit fly quarantine map
California Department of Food and Agricultural

Robert Kenoyer lives just a stone's throw from some of the orchards.

"It's going to impact the ranchers, definitely. You know, the fruit stands," he said.  "It's going to be a hardship. I mean, this is sort of their livelihood here, so, it's going to be tough for them."

No fruit of any kind will be allowed to be sold or shipped from the area unless it can be processed on site, like tomatoes intended for canning. Luckily this happened after most of the area's stone fruits — such as peaches, apricots and nectarines — were already harvested.

Now, the state will begin applying a poison-laced pheromone called "Spinosad" to attract and kill male flies. It's fairly effective, but the ban can only be lifted after the insect has completed three life cycles, which could be 10 months or longer.

"Some people might decide not to produce next year," said Slattengren. "This is pretty, pretty bad for us and for agriculture out here. If this had happened in peak cherry season, everybody could have lost all their crops and stone fruits would be gone. We're lucky it was the time it was."

"Now, it's been a problem in Southern California off and on," said UC Davis entomology professor Dr. Lynn Kimsey.  "I think this may be the first time it's shown up in the Bay Area. But, yeah, we're aware of it. It's potentially a major problem."

Dr. Kimsey said the Oriental Fruit Fly deposits eggs inside just about any kind of fruit, making it easy for it to be transported undetected. That's why the discovery could have international ramifications.

 "It is a 'Number One' quarantined pest for all of our trading partners," she said.  "So, if we have this thing in California, it means that our shipments of fruit from regions inside the quarantine are now stopped.  We can't sell fruit to anybody.  It's potentially a devastating pest from that standpoint."

But the flies were found in a residential neighborhood, so AG officials are pleading with the public not to take any fruit from their trees off of the property.

They said the produce can be eaten, but any fruit that is thrown away should be double-bagged and placed in the container for garbage, rather than green waste.  They said it will only take a moment of carelessness to create an infestation that could last for years to come.

For more information about the eradication effort or to view maps of the two quarantine zones, visit

View CBS News In
CBS News App Open
Chrome Safari Continue
Be the first to know
Get browser notifications for breaking news, live events, and exclusive reporting.