The California Department of Food and Agriculture has expanded the Asian citrus psyllid quarantine by 234 square miles in Tulare and Kern counties.

The quarantine expanded by about 197 square miles in Tulare County in the Exeter and Lemon Cove areas and parts of an unincorporated area southeast of Porterville, according to a news release.

A detection of several of the citrus pests in Porterville also expanded the quarantine into Kern County by about 17 square miles.

The total citrus psyllid quarantine for all of central and Southern California comprises 888 square miles, according to the release.

In a related action, the state has extended the preharvest application time period for approved insecticides to 10 days from seven days.

Growers have the option of removing all stems and leaves in groves within a quarantine zone, or they can treat with an approved insecticide and begin harvest within 10 days of application.

If growers opt for the latter, they must send the fruit to a packer or processor that is approved by the local county agricultural commissioner.

The concern over the Asian citrus psyllid is the insect can carry citrus greening or huanglongbing.

Although harmless to humans and animals, HLB can weaken and even kill citrus trees. It is incurable.

Citrus greening is endemic in Florida, where it has cost the citrus industry billions of dollars in losses.

One positive tree has been in California, and that was in the Hacienda Heights area of Los Angeles County. It has since been destroyed.