They have since spread and are now found from the southern tip of Florida to Virginia. Until recently it was thought the RIFA's range extended only as far west as New Mexico. However, recently established colonies have been found in California s Orange, Los Angeles, Riverside and San Diego counties. Federal quarantines try to prohibit movement of RIFAs by requiring all items from infested areas containing soil or mulch to be treated with an insecticide before transporting them to non-infested areas. However, colonies may move inadvertently in untreated items.
Workers are aggressive when the nest is disturbed and can deliver a painful sting.
Victims typically react to RIFA venom by forming pustules six to twelve hours after the bite. Nest mounds, which can be four foot wide and eighteen inches high, damage yards and athletic fields. RIFAs sometimes damage crops, and can injure livestock as well as wild mammals such as deer, rodents and birds. RIFAs have shown a tendency to nest in electrical boxes, and their nesting activities can damage connectors and cause power outages. An estimated 10.5 million dollars a year are spent by homeowners in Texas in an effort to control the RIFA, and additional 7.9 million is spent annually on medical expenses for the treatment of stings.