Little fire ants have been detected on about 8 acres at Twin Falls in Huelo. ZACH PEZZILLO photo

Getting stung while hiking and swimming at popular Twin Falls in East Maui is what signaled the latest infestation of little fire ants on Maui, the island’s third detection this year, the Maui Invasive Species Committee reported Wednesday.

The infestation area of about 8 acres in Huelo encompasses several homes and some spots frequented by hikers and swimmers.

MISC spokeswoman Lissa Strohecker on Wednesday afternoon said that while hikers aren’t likely to spread the invasive, stinging ants, she encouraged people to “do whatever possible not to move material from an infested area,” as is recommended in any infestation site.

Samples collected downstream from the infestation’s core also show little fire ants; additional survey work will determine if the ants have spread along the waterway.

The infestation was reported in early November by an area resident living in the infested zone and a former MISC employee, both of whom had been stung during separate visits to the popular hiking and swimming spot off Hana Highway, according to MISC.

Survey work by two dozen people, along with MISC and the state Department of Agriculture staff, was done Nov. 14 to determine the size and spread of the infestation.

Strohecker said that based on saturation and spread, the infestation may be about 5-plus years old.

“Once they’re that widespread, it’s hard to trace back to a single incident,” she said. “In an area when people are actively moving things around it can accelerate it.”

A meeting will be held at 6 p.m. Dec. 5 at the Haiku Community Center to discuss what’s known about the Twin Falls little fire ant infestation and plans for eradication.

“We are fortunate to have strong community awareness; public reporting of little fire ants continues to be the most effective way to find populations,” said Adam Radford, MISC manager, in a news release.

There are 10 active sites being treated by MISC. Sites in beginning treatment are Nahiku, Waihee Valley and Twin Falls.

Greatly diminished sites (ants present but treatment efforts have been underway for months) include Kaeleku (outside Hana) and Happy Valley.

Spot treatment areas (ants left in only one or two small areas such as a single tree) are Kapalua and Huelo.

Finally, locations of no known ants but survey work is continuing to ensure they don’t return are a farm in Waihee (Maui’s first detection), in Haiku (small population linked to material moved from Huelo site) and at a South Maui plant nursery.

Visit stoptheant.org to find out more on collecting samples of ants and the status of little fire ants on Maui and throughout the state.

Suspected populations of little fire ants can be reported to the Maui Branch of the state Department of Agriculture at 873-3080 or MISC at 573-6472.

* Kehaulani Cerizo can be reached at kcerizo@mauinews.com.