California state inspectors have trapped two additional Mediterranean fruit flies in San Diego County, prompting state officials to expand the quarantine to 304 square miles.
It had been 106 square miles.
Inspectors also found two properties with larvae on them, according to a news release.
A map of the quarantine can be found at http://pi.cdfa.ca.gov.
The latest infestation, which is centered around Mira Mesa, comprises 27 wild Medlifes.
The California Department of Food and Agriculture has begun an eradication program, which involves releasing sterile male flies over a 13.3-square-mile area.
The theory is the sterile males will inundate the area. Wild females will mate with the sterile males, producing no offspring. Eventually, the population dies out due to a lack of reproduction.
In addition, inspectors will treat properties within 200 feet of a find with spinosad, an organic insecticide.
As part of the quarantine, home owners cannot move host material from the area.
Commercial operations must follow specific protocols to move their produce or plants.
The Medfly can infest more than 260 different crops.
Should Medfly become established, the state estimates it could cause losses of $1.3 billion to $1.8 billion in crop loss, additional treatment expenses and loss of markets.