The state is working to understand the full extent of a little fire ant infestation after detecting a new population at Kauai’s Wailua River State Park.

The current estimated size of the infestation is 13 to 35 acres, according to surveys by the Kauai Invasive Species Committee and the state Department of Agriculture, although it is still being studied.

The infestation is primed to spread, the DOA and state Department of Land and Natural Resources said in a joint news release today.

“The location of this LFA population is concerning because of its proximity to the Wailua River,” Curt Cottrell, administrator of the DLNR’s Division of State Parks said in a statement. “LFA can ‘raft’ along waterways allowing them to spread far greater distances.”

With no ant species native to the islands, the state has prioritized the detection and containment of the LFA, which has caused extensive economic damage — ranging from loss of agricultural productivity to costs to control populations — since making its way to Hawaii island more than 20 years ago.

“Our current priority is to find a solid perimeter of the infestation,” said Tiffani Keanini, KISC manager, in a statement. “After we identify the size and terrain, we begin to develop a response plan, brainstorm management strategies, and list resources needed to address the population.”

Prior to this year, the ant species was established on Kauai in three locations: 11 acres in Kalihiwai in 1999; 2.5 acres in Kilauea in 2019; and 12 acres in Moloaa in 2020. The populations at Kalihiwai and Kilauea have been controlled, and treatment is ongoing in Moloaa.

KISC is asking Kauai residents to collect ants on their properties by “using a smear of peanut butter on several chopsticks.” The peanut butter attracts ants, and the sticks should be collected and sealed in a zip-top bag and frozen for 24 hours to kill the ants.

The bags should then be dropped off or mailed to the KISC office.