Action: American bullfrog control: Application of a biocide
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- One replicated, controlled study in the USA found a number of chemicals killed American bullfrogs, including caffeine (10% solution), chloroxylenol (5% solution), and a combined treatment of Permethrin (4.6% solution) and Rotenone (1% solution).
Biocides may offer a tool for localised eradication or population reduction of American bullfrogs, provided potentially negative effects on native species are carefully managed.
Supporting evidence from individual studies
A replicated, controlled laboratory study from 2008 to 2009 at the University of California, USA (Snow & Witmer 2010) reported that a number of chemicals killed American bullfrog. Caffeine (10% solution), chloroxylenol (5% solution), and a combined treatment of Permethrin (4.6% solution) and Rotenone (1% solution) each achieved 100% mortality. Dosed on their own, Permethrin (4.6% solution) and Rotenone (1% solution) each achieved 40% mortality. In the trial, approximately 4 ml of treatment solution was sprayed on the entire dorsal surface of randomly-selected groups of bullfrogs using a handheld plastic spray bottle. There were five bullfrogs in each group. Water was used as the solvent for all materials. To improve solubility, a small amount of sodium benzoate was added to the caffeine solution, and a small amount of alcohol was added to the chloroxylenol solution.