A 93-square-mile area of Hacienda Heights, Los Angeles County, has been quarantined after the detection of citrus greening disease in a single residential lemon/pummelo tree last week.
The quarantine is centered near the Pomona Freeway, also known as Highway 60, and Hacienda Boulevard, according to a news release.
The area is part of a much larger quarantine already established for the Asian citrus psyllid, the insect that transmits the citrus greening bacterium.
The bacterium can stunt and even kill citrus trees, but it is harmless to humans and other animals.
The new quarantine prohibits movement of all nursery stock out of the area. In addition, it includes existing provisions that only allow movement of commercially cleaned and packed citrus fruit.
Fruit that is not commercially cleaned or packed, including residential or dooryard citrus, cannot be removed from the property on which it is grown. It can, however, be processed or consumed on the premises.
Because citrus greening can remain dormant in citrus trees without causing symptoms for up to two years, the quarantine is expected to last at least that long.
The California Department of Food and Agriculture, the U.S. Department of Agriculture and the Los Angeles Couunty Agricultural Commissioner's office continue to investigate the source of the tree, survey for greening and test for the disease.
In Florida, where greening is endemic, it has caused at least $1.3 billion in lost grower revenue and $3.6 billion in lost economic activity, according to a University of Florida report.