HILO, Hawaii >> Businesses on the Big Island are coming up with their own ways to keep the population of a tiny but noisy frog down. Big Isle firms zero in
on coqui
Star-Bulletin staff
The state recently delayed its plan to use a caffeine spray to eradicate the annoying coqui frogs, whose shrieks, scientists say, can reach up to 100 decibels, as loud as a leaf blower.
Authorities, meanwhile, have been concentrating on the movement of nursery plants and materials as a way of reducing the dime-sized frog's spread.
Coqui frogs are native to Puerto Rico, where they are much beloved, and likely ended up in Hawaii -- where they are an invasive species -- in shipments of tropical plants. Major infestations have been reported on the Big Island, and separate colonies have been found on Maui, Oahu and Kauai.
Last month, two shipments of foliage plants that arrived on Oahu infested with coqui frogs were sent back to the Big Island after workers handling the cargo heard the frogs and alerted agriculture inspectors.
At least a half-dozen other plant shipments have been held on the Big Island because of the frogs, said Melvin Enriques of the Hilo office of the state Department of Agriculture's Plant Quarantine Branch.
At Wal-Mart in Hilo, the frog's now-familiar calls can be heard from the plant department.
The store sprays for the frogs monthly and asks the nurseries that supply the store with plants to make sure the frogs aren't contained in the shipments, said store manager Boyd Schneider.
"We're doing what we can," he said, adding that he and other employees also hand-pick the frogs off plants when they can.
The tiny frogs hide on the ground and in leaf litter during the day, but at night they climb trees and bushes to start their nocturnal calls.
Leslie Hill, owner of Paradise Plants, said she and her employees watch carefully for the little frogs.
"We're being diligent," she said. Periodically cleaning walkways with bleach to stop mold growth may also be keeping the frogs at bay, she said.
Jeff Enriques-Ikeda, manager of Garden Exchange, said his workers use ammonia to clean the floor of their plant area. That agitates the frogs, which makes them more visible and easy to collect.
Enriques-Ikeda said he also wrote to his suppliers to ask them to ensure the plants are frog-free.
"I told them if we get to be known to have coqui it will directly impact them," he said.
The efforts have apparently paid off -- no coqui calls could be heard during a nighttime visit to their nursery areas.
Substances being used on the frogs include hydrated lime, a soil additive which can be mixed with water to form a slurry. Officials say citric acid is also showing promise against the frogs.
A concentrated caffeine spray is also effective against frogs. EPA approval of its use on coqui expires today but may be reinstated later.
Researchers plan to begin field tests on citric acid as a possible alternative pesticide. Laboratory tests in Hilo showed that the acid is an effective and inexpensive pesticide for controlling the coqui.
County of Hawaii
Department of Agriculture
