93 Miles of County Quarantined Due to Fruit Fly Infestation

The Mediterranean fruit fly (or Medfly) can cause severe danger to California agriculture exports

A portion of San Diego County has been put under quarantine after four adult male Mediterranean fruit flies were found in the La Mesa area.

The Mediterranean fruit fly (or Medfly) can cause severe danger to California agriculture exports because they can infest up to 250 different types of fruit and vegetables.

The quarantine is affecting 93 miles of San Diego county, bordered on the north by Prospect Avenue, on the South by Mount Miguel Road, on the west by Fairmount Avenue, and on the East by Vista Grande Road. The quarantine will only affect growers, wholesalers and retailers of susceptible fruit in the area. 

In order to eradicate the infestation, the United Sates Department of Agriculture (USDA) is working with the San Diego County Agricultural Commissioner and the CDFA to release sterile male Medflies into the affected area.

The release of these sterile flies began on August 10th at a rate of 250,000 per week.

While it may seem counter-intuitive to release more flies into the environment in order to stop an infestation, the sterile insect rearing facility in Los Alamitos has proven that this technique works.

When sterile male Medflies are released, they mate with fertile female flies but do not produce any offspring.

As the Medflies reach the end of their life cycle, they die off without ever producing a new generation of flies to replace them, thus decreasing the entire population. This technique is used on a daily basis over the Los Angeles basin in order to keep Medfly populations low all across Southern California.

In addition to releasing sterile male flies, properties within 200 square meters of detected infestations are being treated with an organic formulation of Spinosad.

Originating from naturally-occurring bacteria found in the soil, Spinosad is being used to eliminate any mated females and reduce the overall density of the population.

The final step towards containing this outbreak is the removal of fruit within 100 meters of detected areas to prevent the spread of any fruit infested with Medfly eggs or larvae.

If you are a home gardener, it is recommended that you do not take your produce off site until the Medflies are under control.

If you believe you fruits and vegetables may be infested with Medfly larvae, you are encouraged to call the state’s toll-free Pest Hotline at 1-800-491-1899. A current map of the quarantine can be found by clicking this link.

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