ROD THOMPSON / RTHOMPSON@STARBULLETIN.COM|
Puna resident Clive Cheetham pours bags of hydrated lime into a 1,000-gallon tank, preparing a lime-and-water mixture used to kill noisy coqui frogs. Neighbor Fattah Day help with plumbing at the base of the tank.
HILO » The Puna coast soil is sweet with lime, and the screeching coqui frogs are dead.
"I'm just thanking God every minute it's quiet," said a woman known simply as Tao, whose land was infested.
In the late 1990s, as Big Island populations of the non-native, night-shrieking frogs threatened the natural environment and human sleep, caffeine and citric acid were proposed to kill them. Both were expensive and had drawbacks.
Now hydrated lime is the frog killer of choice, following experimental testing by an informal partnership of state officials and community residents.
Treating an acre with citric acid to kill the frogs costs $1,000, said Clive Cheetham, Tao's neighbor in the Koae area of Puna. Lime does the job for $75, he said.
The lime, commercially derived from limestone, is normally sold to sweeten soil, or reduce its acidity.
"All of my ornamentals are better than ever because the soil has been sweetened," said Tao, whose Koae property became a test site for Cheetham and others.
But except for research, using hydrated lime to kill frogs is illegal.
The U.S. Environmental Protection Agency authorizes "labels" for chemicals outlining permitted uses. No label approves lime for killing frogs. A manufacturer who sells lime knowing it is used to kill frogs faces heavy fines, said state agriculture official Bob Boesch.
State officials found just one hydrated-lime manufacturer with a label for lime as a disinfectant. The state now hopes to piggyback on that, obtaining a "special local need registration" for frog eradication. A ruling could come within 90 days after paperwork is submitted, Boesch said.
One concern is the possible effect of lime on whelping hoary bats, bats with "pups," Boesch said. The label would have to include a warning about them, he said.
Legal restrictions have meant slow going for lime while coquis literally flood the Big Island. Recent heavy rain washed them miles down stream beds, starting new infestations.
The idea of lime as a frog killer started at least two years ago. State Department of Agriculture staffer Kyle Onuma noticed the stuff irritated his sweaty skin while he used it on his ginger farm.
By summer 2002, University of Hawaii researcher Arnold Hara showed it killed frogs on test plots.
Cheetham heard about lime at a community meeting in March 2003. "I said, 'Let's rock and roll, let's do something,'" he said.
Cheetham bought a 1,000-gallon, globelike tank and a trailer. Hara obtained research money. Some neighbors kicked in $1,000 each. The county Fire Department donated a hose. It was still research on a shoestring, about $8,000 in all.
Next came the plumbing. Hydrated lime, a white powder, does not dissolve in water.
"It settles like cement to the bottom," said Cheetham's partner, Fattah Day. "The first time we used it, it went right into the pipes and clogged everything."
Finally the pipes and pumps worked, producing the "drench" they needed.
The frogs were wearing Tao out. "I couldn't sleep. I was wearing earplugs every night. I was on antidepressants," she said.
The drench killed most of her frogs. She killed survivors by throwing dry powder at them.
"I come out white. There's white powder on my face," she said.
Frog eggs hatched and the frogs came back. Cheetham expected a second application would be needed.
"It's a long-term thing. You don't just go out and magically get rid of it," he said. "The goal is to convince the deep pockets of the federal government that it's doable."
Cheetham recently conducted another drenching in thick elephant grass using a new technique. He and friends listened at night and marked frog areas. But instead of drenching at night, they applied lime during the day.
Only one screeching frog survived.
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Steam scheme kills
Big Isle infestation
HAWI, Hawaii » West Hawaii resident John Tanaka found he couldn't powder his coqui frogs, so he steamed them.
Tanaka owns five acres in North Kohala, covered until recently with a 3-foot-thick blanket of California grass infested with coquis.
Last year, Tanaka used a borrowed machine to blow 120 bags of lime powder into the grass. He still had frogs. He sprayed 35 bags of citric acid dissolved in water. He still had frogs.
"You've got to make a direct hit" to kill them, he said. With five acres, that's hard.
Finally, in December, he bulldozed the entire property, pushing the frog-laden grass into a pile.
Then he took a steam-producing machine, like the kind that cleans car engines, but bigger, and pumped steam and hot water for two hours. When he saw steam coming out of the top of the pile, he stopped.
The coquis were dead. "But we are continuing our vigilance, not relaxing," he said.