American bullfrog control: Application of a biocide

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Key messages

  • 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).


About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. 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.

    Study and other actions tested
Please cite as:

Aldridge, D., Ockendon, N., Rocha, R., Smith, R.K. & Sutherland, W.J. (2020) Some Aspects of Control of Freshwater Invasive Species. Pages 555-87 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Control of Freshwater Invasive Species

This Action forms part of the Action Synopsis:

Control of Freshwater Invasive Species
Control of Freshwater Invasive Species

Control of Freshwater Invasive Species - Published 2017

Control of Freshwater Invasive Species Synopsis

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What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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