South Kona farmers grow wise to little fire ants

  • Little Fire Ants drawn out to peanut butter (Courtesy photo)

KAILUA-KONA — It wasn’t long ago that the better part of West Hawaii’s agriculture industry paid little mind to an invasive pest ravaging Hawaii Island’s windward shores.

But in subsequent years, little fire ants have captured the attention of South Kona farmers.


Heather Forester, extension specialist at Hawaii Ant Lab, said the problem was prevalent five years go, but it wasn’t until the last couple flips of the calender that purveyors of West Hawaii farms took real notice.

“Nobody was willing to pay attention. They looked at it as a Hilo problem even though we were receiving positive samples,” Forester said. “People are more reactive than proactive. What I think is happening is the population has exploded so much, the ants are raining down on people. They’re getting stung and realizing they have a huge problem in their backyards or on their farms.”

Ken Love, president of Hawaii Tropical Fruit Growers, called Forester to attend the group’s monthly meeting Monday night in South Kona. He said the audience was populated primarily by otherwise infrequent attendees, highlighting the threat LFA poses to crop yield and the pervasiveness of that message after years of what seemed relatively futile circulation.

“There’s a lot more fire ant infestation now,” said Love, who’s been farming the area for decades. “They’re starting to see more infestations on Middle Keei Road.”

The Hawaii Ulu Cooperative has dealt with infestations at its nursery spilling over from a neighboring property. And Dr. Kurt Weigelt, who owns and operates A Beautiful Edge of the World B&B on an active farm said he’s found little fire ants in his coffee crop as well as several other varieties of fruit trees.

The primary threat to crop yield is a lack of pickers who are willing to suffer LFA stings day after day. Weigelt has kept a handle on the problem for his workers so far, but advocated for more cooperation and less denial throughout the agricultural community when it comes to LFA.

“Nobody wants to say, ‘Oh I’ve got it.’ It’s like having a disease,” Weigelt said. “That’s not going to solve the problem. People have got to work together and say, ‘Hey, I tried this or I tried that.’”

As an organic farmer, however, Weigelt’s views on the most appropriate way to address the problem diverge from those promoted by Hawaii Ant Lab.

The lab offers homeowners multiple solutions for treating LFA. But for farmers, there’s only one route to travel — Tango. The chemical product is the only pesticide cleared for use on crops.

Forester said a crucial element of the Tango treatment regimen is the gel bait carrier, into which the Tango is mixed and which serves as the substance that makes it appetizing to the ants. Acting as an insect growth regulator, or essentially a form of birth control, the workers take the Tango-infused bait back to the queen and the colony slowly dwindles.

“We do not have any organic bait options that are legal for use right now that are effective for fire ants,” Forester explained. “But the Hawaii Ant Lab is looking into organic options, which would be down the line. … We do recognize it’s an issue for organic farmers.”

Weigelt said he’s had some success using an organic treatment of Borax, also known as sodium borate, in controlling his LFA population. He mixes the substance with sugar and peanut butter.

“I’d rather go the cheaper, more organic route first,” said Weigelt, adding if it ultimately fails he’d resort to other options. “I like experimentation rather than just dumping chemicals.”

Forester explained that absent a bait for worker ants to carry back to the queen, control is the best anyone can hope for. Eradication would be next to impossible, especially considering the proliferation of LFA in West Hawaii over the last half decade.

The effectiveness of Weigelt’s method in returning the compound to the queen and what kind of impact it has in the nest if it makes it there is difficult to gauge as it hasn’t been formerly tested on a large scale.

Forester encouraged any farmers concerned about an LFA infestation to contact her at Hawaii Ant Lab about starting Tango treatment. The lab’s phone number is 808-315-5656. The website can be found at


Eventually, Hawaii Ant Lab plans to station a permanent employee in West Hawaii who will handle extension duties similar to those managed by Forester, as well as conduct ant identifications and surveys at green waste disposal areas and the island’s ports of entry.

However, no timeline for the establishment of that position has yet been determined.