Hi'iaka's Healing Herb Garden

Coqui Experts Gather in Hilo

Coqui frog experts gathered in Hilo Feb. 7 through 9 for the First International Conference on the Coqui Frog. Sponsored by the Hawai‘i Island Coqui Frog Working Group, this conference drew together scientists and other experts from as far away as Pennsylvania and Australia. Other problematic amphibians were also discussed, such as the Cuban tree frog and the highly invasive Bufo, or cane toad. University of Hawai‘i at Hilo researchers and other Big Island experts presented specific findings about population density in Hawaiian forests, skin hydration, sound levels, parasites that might be helpful in controlling their numbers, and techniques for controlling this noisy pest.

Representatives from the various islands’ invasive Species Committees were also in attendance. During a panel discussion with members from O‘ahu, Kaua‘i and Maui, encouraging reports were presented regarding the success of eradication efforts on these islands. Keren Gunderson of the Kaua‘i Invasive Species Committee reported that early detection of a coqui invasion near Lawai was contained in 2005 after the formation of a Coqui Frog Working Group. Land was cleared, traps were employed, and spraying of both lime and citric acid was done. Dr. William Mautz of UH-Hilo summed it up by saying, “rapid response to new invasive species is key.… These synergistic conversations will make a difference in our ability to manage this frog and other invasive species.”

Comparisons of the coqui in its native Puerto Rico are helpful in learning about this creature in Hawai‘i and understanding its habits so we can better control it here. Forests in Puerto Rico are very different from those in Hawai‘i because Hawai‘i has far more “understory plants,” or low shrubs that cover the forest floor under large trees. Such an understory provides perfect daytime cover for the coqui, and by keeping areas cleared of this foliage, we can be instrumental in keeping the frog away from our homes better than if we allow the underbrush to choke out the open ground. As was said, “choke shrubs, choke coquis.” Since most of the understory in Hawai‘i consists mainly of invasive plants, this is an important practice for homeowners to attend to—it keeps the non-native plants at bay AND controls potential invasions of coqui frogs. The leaf litter created by some invasive species such as trumpet trees (Cecropia obtusifolia) provides excellent habitat for the frogs, so keeping your yard well raked is a good way to discourage the frogs from taking up residence. Another trick that Hawai‘i homeowners can use is to fill cracks in a‘a lava with cinder. The practice of “ripping” your lava, which essentially turns a pahoehoe flow into an a‘a flow, only encourages coquis by providing a habitat for them.

The Conference did not focus on control or eradication: It included primarily reports of the scientific research conducted by the world’s experts. Knowledge is power and if we can learn more about coqui frogs and other bothersome invaders, we can learn to control them without the use of citric acid, lime, or other types of chemical controls.

Chemical controls were discussed, however. David P. Davis, Ph.D.of Ono Loa Orchards in Kurtistown presented a poster about a new product he has developed that is effective in controlling the frogs. This new product (ACS-P) is made from Acidic calcium sulfate which is a nontoxic agent that is approved for use by the Food and Drug Administration and the USDA. Its ingredients are generally regarded as safe (GRAS) and it is effective because of its high concentration of hydrogen ions and its low corrosive effect on human skin. But when applied to a Coqui frog, it is quickly absorbed and very lethal. Dr. Davis believes that the EPA might approve ACS-P for emergency use as a “minimal risk pesticide for use against coqui frogs.” For more information email him at coquicontrol@gmail.com.

Dr. Mautz helped to conclude the Conference with a Hawaiian expression: “I kahiki no ka hao, o ke ki‘o ana i Hawai‘i nei,” or “In kahiki [faraway lands] was the iron, in Hawai‘i the rusting.” In other words, certain species might be beneficial in their native lands, but when they come here they can become a nuisance. The coqui frog is not evil: it is merely taking advantage of our favorable environment to sustain its survival.

Chinese philosopher Sun Tzu, author of the 2,300-year-old treatise The Art of War, warned, “If you know yourself but not your enemy, for every victory gained you will also suffer a defeat.” This definitely applies to environmental pests such as the coqui frog and is a major reason why conferences like this are valuable in teaching us how to safeguard our precious ‘aina and way of life.

On the Web:
ctahr.hawaii.edu/coqui/conf08.asp#ConferenceDescription hear.org/starr/hiplants/images/thumbnails/html/cecropia_obtusifolia.htm
antiwar.com/pena/?articleid=9755