Officials battle 'highly aggressive' red imported fire ant infestation in Southern California

Agricultural officials in Southern California are battling an active infestation of red imported fire ants that are "highly aggressive in nature," and pose a risk to California's agricultural economy.

The infestation occurred at a private property in Montecito, in Santa Barbara County, according to a recent press release from the Santa Barbara County Agricultural Commissioner’s Office.

Located over 90 miles north of Los Angeles, Montecito is best known as a celebrity enclave with Oprah Winfrey, Ellen DeGeneres, Prince Harry and Meghan Markle among the town's residents.

Officials did not name the owners of the private property.

Venom released from the ants' stings can cause "painful pustules on the skin, and can be particularly dangerous, even fatal, to sensitive groups or those with an allergy to the venom," officials said in the July 18 release.

Red imported fire ants, Solenopsis invicta, pose "an immediate threat" to California's agricultural economy because they require a quarantine of nursery products, officials said.

The ant species is native to South America but has established populations in parts of Southern California, particularly in Los Angeles, Orange, and Riverside Counties. The first recorded presence of the species in California was in 1984.

Siavash Taravati, an entomologist and integrated pest management advisor with the University of California's Cooperative Extension offices, noted the distinction between this species of ants and ants native to California.

Native fire ants and argentine ants appear similar to red imported fire ants in size and color but the quickest way to differentiate them is by their "aggressive behavior," Taravati told ABC News.

The ants' stinging behavior is hazardous to fieldworkers and infestations can clog irrigation systems and damage electrical wiring, Taravati said.

The presence of red imported fire ants is known to increase the cost of fruit picking in the region, according to Taravati, due to the health dangers associated with the species.

The ants can also threaten wildlife and displace native ant species, Taravati said.

This is the only known active infestation in Santa Barbara County, according to officials, who said there are currently no red imported fire ant quarantines in place.

The infestation is believed to have originated from a nursery stock shipped from Riverside County in September 2023, which was infested by the red ants and spread to the surrounding property.

Santa Barbara County Agricultural Commissioner’s Office staff are conducting regular surveys of the impacted property and determining appropriate treatments by a licensed and registered pest control business, according to the release.

Officials are working in collaboration with the California Department of Food and Agriculture, the University of California Cooperative Extension (UCCE), and Riverside County Agricultural Commissioner’s Office staff.