State scrambles to contain little fire ant infestation on Kauai covering at least 13 acres

The Kauai invasive species council says this is the fourth known infestation.
Published: Oct. 13, 2022 at 5:53 PM HST|Updated: Oct. 13, 2022 at 6:01 PM HST
Email This Link
Share on Pinterest
Share on LinkedIn

HONOLULU (HawaiiNewsNow) - Invasive species experts on Kauai are working to get a handle on an emerging threat as an infestation of little fire ants has been found at the Wailua River State Park.

The ants are tiny, measuring about one-sixteenth of an inch, but they pack a serious punch and are one of the state’s most serious invasive threats.

Colonies can feature millions over a large area and work is underway to limit the spread.

“From my experience, they’re much more difficult to control than any of the other species I’ve worked with in the past,” said Casper Vanderwoude, who heads the state’s Hawaii Ant Lab.

Vanderwoude, who has more than 30 years of experience studying the tiny pests, said the little fire ants likely came to Hawaii about 20 years on an object shipped or flown in.

Unlike other ants, these love shade, live on the ground and tree canopies.

They also have the ability to multiply quickly.

“The sheer number of fire ants in a particular site can be overwhelming,” Vanderwoude explained. “If you can imagine, an acre of land could have as many as 80 million ants, so it’s very hard to get away from.”

Hence the urgency in Wailua.

The Kauai Invasive Species Council says this is the fourth known infestation and while its still trying to figure out the exact size, this one is already the largest ― covering at least 13 acres.

“We are surveying the area and that’s a little bit difficult because of the terrain,” said KISC project manager Tiffani Keanini. “It’s very steep terrain, requires skilled rappelers to go down the terrain to search for little fire ants to see how far down the valley it has gone.”

Once the size is determined, treatment can begin.

Complete eradication is costly, however.

In the past, the council and Ant Lab have had success with a solution that’s safer than pesticides and does the job.

“It’s a bait that’s more like mayonnaise than it is like dry granules and we can shoot that stuff into the trees,” Vanderwoude said. “It sticks to the vegetation where the ants can then harvest it and then again, bring those nutrients and the toxins back to the nest.”

Residents are also encouraged to check their backyards.

“You’re not gonna detect them unless you’re testing you’re yard for them,” Keanini said. “That’s also concerning because by the time we know where they are are at, it’s already a larger infestation to go after and treat.”

Exercise caution around the ants as their bites are painful and can result in significant swelling.

For more information on how to test for ants and submit samples, click here.