In southern California, imported fire ants have been found in Orange, Los Angeles, Riverside, and San Bernardino counties. In Orange County, the heaviest concentrations have been in the north and south areas. In Riverside County, the heaviest concentrations are in the Coachella Valley. In the Central Valley, imported fire ants have been found mostly in almond groves in Madera, Merced, Fresno, and Stanislaus counties. A couple of sightings have been reported in Sacramento. The most recent expansion in southern California has been eastward from Los Angeles and Orange counties into Chino Hills and Ontario of San Bernardino County.
The following eXtension website may be useful:
Fire Ants in California
