Oriental fruit flies found in Sacramento, county says. Here’s the plan to eradicate them

A local infestation of oriental fruit flies, an exotic invasive species that attacks over 230 different fruits, vegetables and plants, has been found in Sacramento, county officials said Tuesday.

To date, 14 flies have been found at a handful of residences near the intersection of Stockton Boulevard and Elder Creek Road, according to a news release from Sacramento County. The flies are mostly males, but one female fly was found, leading officials to believe there will be additional breeding.

Juli Jensen, the county’s agricultural commissioner, said local at-risk products include grapes, pears and orchard crops. This isn’t the first time these flies have been detected in the county and it’s also not the first infestation. The last oriental fruit fly infestation was in 2007, in North Highlands.

But this infestation will likely be more challenging, Jensen said.

“There are a lot of backyard fruit trees and hosts,” she explained. “There’s a lot of host material out there. Much more than there was in the North Highlands area where that infestation was.”

Crops are made inedible once a female fruit fly lays its eggs inside a fruit. These eggs then hatch into maggots, which “tunnel through the flesh of the fruit,” according to the news release.

The infestation has triggered both a treatment protocol as well as a quarantine.

Jay Van Rein, a spokesperson for the California Department of Food and Agriculture, said residents who live in the quarantined areas should not move their fruits and vegetables — all produce should be consumed on site, it should not be shared or sold. Individuals who sell produce grown in the quarantined area will have to sign a compliance agreement saying they will not sell.

The quarantine will take effect in the next day or two, Van Rein said, but the CDFA is already enforcing compliance agreements “with the residents and businesses in the immediate area where the infested properties are.”

The eradication treatment will consist of the application of 600 bait stations, attached to utility poles and trees. These stations will contain a mix of methyl eugenol, which attracts male flies, and insecticide. The CDFA’s website explains these stations kill fruit flies before breeding can take place.

Map of fruit fly quarantine and treatment areas in Sacramento County
Source: Calif. Dept. of Food and Agriculture
The Sacramento Bee

A ground treatment may also be used if there is a residence with a breeding population on its premises. Such a residence may also be subject to fruit removal, at which time all host fruit in a 100 meter radius around the site of breeding may be removed and disposed of.

Residents impacted by bait sprays or a potential fruit removal will be notified 48 hours in advance, according to the CDFA.

Jensen strongly urges residents with crops in the affected areas not to remove the “host materials” from their property and instead call the county’s Agricultural Commissioner’s Office.

“Don’t put it in your green waste so that it gets picked up by the county,” she said. “They need to double bag it in plastic bags and we will come by and pick it up and properly dispose of it so it does not spread. We don’t want this to be any bigger than it already is.”

The county press release also states a quarantine in a 4.5-mile radius will be established.

According to the department, the establishment of an oriental fruit fly population could potentially result in the economic loss of hundreds of millions of dollars through the destructive of native plants and fruits.

These flies are “widespread” in Southern Asia, Sri Lanka and Taiwan, the release explains, and pests typically enter the state by “hitchhiking” in the fruits and vegetables illegally brought back by travelers returning from infested places.

The fruit flies, which do not pose a threat to human health, were detected through the commissioner office’s detection program, which traps on a regular basis in an effort to find invasive species as early as possible. Once a species, like the oriental fruit fly, is first detected, the office adds additional traps in the area.

On Thursday, a meeting for growers will be held to discuss the quarantine at the Walnut Grove Library from 5-7 p.m.

The CDFA will inform affected residents through initial outreach consisting of door knocking.

“When we detected the flies, our staff began walking/driving the immediate area around the detection sites to inform residents in person, set additional traps, take fruit samples to look for fruit fly larvae, and make preparations for the coming quarantine,” Van Rein said.

Once the initial rounds are completed, the department will announce the quarantine and produce a detailed map.

“The county is also taking the lead on informing and meeting with farmers in the region,” Van Rein said. “We are also advising farmers market managers, and working with related businesses such as fruit handlers/packers/shippers, plant nurseries and landscaping companies who may be covered by the quarantine restrictions.”

Anyone with questions may call the commissioner’s office at 916-875-6603.