The California Department of Food and Agriculture has quarantined 178 square miles of Tulare County after Asian citrus psyllids were trapped in three locations near Porterville.
The quarantine in the heart of the state's citrus-producing region prohibits movement of nursery stock out of the area. It also requires that all citrus fruit be cleaned of leaves and stems before moving out of the area, according to a news release.
An exception is made for nursery stock and budwood grown in U.S. Department of Agriculture-approved structures designed to keep psyllids out.
Residents with dooryard fruit within the boundaries are barred from taking it out of the quarantine area.
In addition to Tulare County, Asian citrus psyllid quarantines are in place in Ventura, Santa Barbara, San Diego, Imperial, Orange, Los Angeles, San Bernardino and Riverside counties. More than 45,000 square miles fall within those quarantines.
The concern is Asian citrus psyllids can carry citrus greening, also known as huanglongbing, a lethal citrus disease. But the bacterial disease is harmless to humans or animals.
So far, only one psyllid has tested positive for the disease, and it came from the Hacienda Heights area of Los Angeles County.