Posted on: Sunday, September 7, 2003
Assault on O'ahu coqui planned
Associated Press
State and federal officials are planning to use up to 900 gallons of a citric acid solution this week to rid O'ahu of its only wild colony of the noisy coqui frogs on nine acres in Wahiawa.
Tomorrow night, workers will use 100-gallon motorized sprayers to spray the frogs with a 16 percent citric acid solution in what will be the largest coqui frog kill on the island. Citric acid has been successful in killing the frogs on other islands.
"This is the only wild population on O'ahu," said Scott Williamson, invasive species technician with the Department of Land & Natural Resources' Forestry and Wildlife Division.
Officials hope to eradicate the frogs on O'ahu and avoid what happened on the Big Island. In 1999, there were three known locations of the quarter-size frogs on Maui and five on the Big Island. Today the noisy frogs have colonies at more than 200 spots on the Big Island, 40 or more on Maui and one on Kaua'i.
The Puerto Rican frogs likely ended up in Hawai'i in shipments of tropical plants.
The frogs have turned up in other areas of O'ahu — at nurseries in Hale'iwa, Kahalu'u and Waimanalo — but have been contained, officials said.
In Wahiawa, where the frogs have infested an area that runs from the residential area of Wahiawa Heights to East Range at Schofield, the citric acid will be sprayed at night on trees and on foliage.
The acid solution is about double the strength of lime juice and is considered safe, causing minimal damage to plants. Williamson said officials hope to get the coqui frog numbers down so agencies can control the population using backpack sprayers.
In February, the frogs were reduced to "practically nothing" in one area by hand-picking, said Nilton Matayoshi, chief of the Chemical/Mechanical Control Section of the Department of Agriculture's Plant Pest Control Branch. But not all were killed, their eggs hatched, and the population rose to more than 100, he said.
"It's like controlling weeds," he said.
