Friday, July 11, 2025

Orange County had an invasive fly problem, here’s how they handled it

Dealing with a fly infestation at home is annoying. Orange County had one that spanned almost 100 square miles.

But officials have announced they’ve won the year-long battle against the oriental fruit fly, an invasive species threatening the county’s food supply.

The oriental fruit fly can lay its eggs in more than 200 different fruits, vegetables and plants. Once hatched, the larvae or maggots can quickly spread through a tree’s bounty, feeding as they go, leaving a waste of decayed fruit behind. Leading the fight against the pests was Orange County Agricultural Commissioner Jose Arriaga and his staff, whose mission is to protect local agriculture and the environment.

Officials detected the infestation when eight fruit flies were found in a network of traps regularly monitored throughout the county. Just those few were enough to trigger a quarantine that restricted what agricultural goods could be moved across county lines.

This time, the oriental fruit fly invasion was found in residential areas, but an infestation of agricultural land could have been devastating.

“Nobody’s gonna buy tomatoes full of maggots,” Arriaga pointed out.

An outbreak can ruin a whole season’s harvest. Even if a crop survives, farmers can’t export their goods and most quarantine requirements force them to destroy the harvest entirely.

An infestation can put farms out of business.

“They work the entire season to cultivate the soil, to water the plants, and then you end up finding that it’s under quarantine and you can not move it and you may have to destroy it,” Arriaga explained.

Once the fruit flies were detected, inspectors deployed some 800 traps around Orange County to track the infestation.

A dark grey gel was sprayed onto utility poles and street lights across the county — 600 times per square mile around each detection site. The gel, harmless to humans and out of reach of pedestrians and animals, contains an organic pesticide that kills the male flies.

It took vans driving city streets and spraying poles and posts for at least seven months, or until three fly lifecycles passed, for the quarantine to be lifted.

Inspectors also destroyed more than 2,000 pounds of backyard fruits possibly harboring fly larvae. Arriaga said residents were understanding, recognizing how much was at stake.

First line of defense

To defend residents and growers from invasions, officials work to stop pests at the door.

They enlist the help of Bear, a chocolate Labrador Retriever and professional detector dog. Bear works with his handler, agricultural inspector Vanessa Ochoa, to catch packages entering the county with unmarked agricultural goods, potentially dangerous hosts for invasives.

Their day starts at 6 a.m. when most mail is sorted. Bear walks through distribution centers for FedEx, UPS and other carriers, stopping packages that smell of produce or plants.

Ochoa is trained to see changes in Bear’s behavior and uses certain phrases to direct him. Bear needs to be 98% accurate.

“I have commands and words like ‘What you got?’ and he’ll show me, ‘It’s here, it’s around here,’ and I’ll motivate him and tell him he’s onto something,” Ochoa said. “Seeing his change in behavior and seeing how excited he gets is what helps me pick up speed and motivates me to find more.”

The 40,000 packages human inspectors check in a year, Bear can clear in around four days. When Ochoa intercepts an insect-infested package, she said she feels the impact her work can make in her community and for local farmers.

“We’re here to be public servants and protect the public and our industry. That really sets a purpose for me, everyday coming in and doing what we do,” Ochoa said. “And I have the best partner to do that with.”

Bear stops potentially catastrophic agricultural packages every week, Ochoa said. Recently, they intercepted a package with mangos coming from Mexico. Inside the fruit, they found Mexican fruit fly larvae, a pest not established in California and known to cause economic and environmental harm.

Bear has also caught infested kumquats shipped from China and durian from Thailand. So far, he has blocked more than 200 pests from entering the county, according to department officials.

Soon, the duo may take on a graveyard shift, working until 2 or 4 a.m. to monitor USPS facilities. But since Bear can only monitor one carrier at a time, the detector dog team plans to recruit a new canine this year.

Impacts of an invasive infestation

The county produces around $90 million in agricultural goods every year, so an outbreak can hit the economy. Just as devastating, Arriaga said, is the damage to the county’s ecosystems and natural resources.

“These pests and diseases, they don’t see a difference between a plant in a farm and a plant in the landscape and in our natural environment, and they’ll equally decimate it,” he said.

Addressing a quarantine can also lead to higher pesticide use, which takes an environmental toll and can have human health risks.

During previous regional quarantines, when nothing could be brought into Orange County, food banks that rely on imported produce struggled to stock their shelves. They called Arriaga for help.

Working with the state, Arriaga was able to allow transport from certain areas in the quarantine to Orange County food banks, bringing fresh fruits and vegetables to families. He said he is here for residents and they can always call his office with questions.

“We are a resource locally here in Orange County, to assist them to make sure that they’re not only doing what’s legal, but also what’s protecting our local environment and our food supply,” Arriaga said.

Although his office works to prevent any infestations, Arriaga said the public needs to understand how to avoid triggering a quarantine and what to do if one happens.

Residents in quarantine zones should not harvest fruit from a backyard tree or ship produce outside the county because it could contain larvae. He also warns that shopping online for plants or fruit can have consequences.

“You may inadvertently, accidentally import a disease or a pest,” Arriaga said.

Arriaga and his staff operate their network of traps yearround to detect if another infestation develops. His office is also in charge of inspecting farmers markets, organic produce, and agricultural wholesalers — 20 different programs in all.

To track quarantine areas, visit cdfa.ca.gov.

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