Pesticide for SE Texas 'crazy' ants approved by EPA

Help may be on the way for Houston-area residents driven to wits' end by the relentless attack of crazy Rasberry ants, which have caused damage estimated at $30 million in Harris and six other Southeast Texas counties.

Acting on a request by the Texas Department of Agriculture, the U.S. Environmental Protection Agency on Tuesday approved a crisis exemption for use of fipronil (Termidor SC) on crazy ant infestations. The crisis exemption is in effect until the EPA rules on the state's request for a specific exemption so the pesticide could be used for three years.

Crazy Rasberry ants, called "crazy" because of their zigzag march and named after Tom Rasberry, the Pasadena exterminator who discovered them in 2002, now infest Harris, Brazoria, Galveston, Jefferson, Liberty, Montgomery and Wharton counties.

The rice-grain-size ants, which can bite but not sting, have a penchant for infesting electrical devices and have been blamed for the failure of computers, sewage pumps and electric gate motors.

Agriculture spokesman Bryan Black said only licensed exterminators can apply the liquid pesticide, which kills by short-circuiting the insect's central nervous system and is approved for treating termite infestations.

Jason Meyers, a Texas A&M University doctoral candidate who is considered an expert on the ants, said the poison likely will be an effective management tool of the pests but "not an end-all."

"It should be useful for individual homeowners," he said, "but it's not going to eradicate the ants from any area. Not by any means."

Some studies have shown the poison can wipe out 95 percent of specific insect populations in three days. The EPA considers fipronil moderately toxic and a possible human carcinogen.

allan.turner@chron.com