STAR-BULLETIN FILE PHOTO / 2001 A coqui frog is small, but its shrill cry makes it a big nuisance. This one was caught last July in Wahiawa Heights.

Lime water to be
tested against frogs

The state abandoned using caffeine
because of too much red tape

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By Rod Thompson
rthompson@starbulletin.com

HILO >> State officials will use a new weapon today in the battle to quiet noisy coqui frogs: lime water.

Workers will spray hydrated lime in one acre of non-native forest on the edge of Hilo as a test of how well the watery solution works.

The frogs, native to Puerto Rico and no bigger than a quarter, have ear-piercing screeches and often screech all night.

"We've had calls from people who were practically in tears saying, 'I'm going crazy,'" said Randy Bartlett, chairman of the Maui Invasive Species Committee. "That's just from one frog."

The frogs can reach concentrations of 10,000 per acre.

For a while it looked like the answer was a concentrated solution of caffeine, which knocks the frogs dead. But the U.S. Environmental Protection Agency attached so many conditions -- such as counting how many creatures besides frogs are killed by the caffeine -- that commercial nurseries do not want to use it.

And concentrated caffeine is expensive.

So state agriculture official Lyle Wong came up with lime as a potential new frog poison.

Hydrated lime is inexpensive, has killed coqui frogs in small tests, and is already in widespread use by farmers to neutralize acidic soil.

The purpose of today's test will be to see whether the lime kills enough frogs to lower the sound they make in a given area, Wong said.

Wong cannot recommend lime as a frog killer because the EPA has not approved it for that. If tests are successful, the state would ask the federal agency for approval, but that will take time. Approval of the caffeine took about six months.

Meanwhile, there is the question of what to do with three tons of caffeine sitting in canisters in a Hilo Harbor warehouse.

Wong said he is thinking about providing it to Bartlett's committee on Maui. Bartlett said his group has people who are qualified to use it according to EPA standards.

The Big Island had 226 frog infestation sites earlier this year, while Maui had 41, followed by Kauai with 21 and Oahu with 20.

But all islands could quickly have more. "It's just a matter of time unless someone does something about it," Bartlett said.