How to Stop Coqui Frogs in Hawaii With Lime & Citric Acid

The coqui frog has been distinguished as an unwanted species in Hawaii since 1988. The University of Hawaii College of Tropical Agriculture and Human Resources (CTAHR) calls the coqui frog a threat to the Hawaii ecosystem. According to CTAHR, the frogs are a danger to the survival of Hawaii's insect species and they compete for the same food supply of endemic birds and other native fauna. The Hawaii Department of Agriculture and CTAHR are part of a multi-agency campaign against the frog, which has no natural enemies to keep it in check.

Things You'll Need

• Citric acid
• Water
• Applicator/sprayer

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Instructions

• 1

  Assess the scope of the problem. If there is a large infestation on your property and you reside in Hawaii, contact the State Department of Agriculture or the CTAHR for their advice, input and any new advisories.

• 2

  Prepare the area targeted for spraying. In order for the spraying to be the most effective, remove dense shrubs, weeds and dead foliage. This will increase the likelihood that the spray will contact the frogs and their eggs.

• 3

  Determine the size of the infested area to be sprayed. Knowing the scope of the problem and the area to be covered will provide the basis for determining how much spray will be required.

• 4

  Use a citric acid solution as a spray. Although the EPA issued a temporary exemption for the use of hydrated lime in sprays in 2005, the currently accepted and recommended spray (as of late 2010) is a citric acid solution. Hydrated lime usually leaves spots on leaves. The preferred and recommended method is the citric acid solution. The EPA considers citric acid safe for use.

• 5

  To mix your own spray, add 1.3 pounds of citric acid per 1 gallon of water. Citric acid is packaged in 1, 5 and 50 pound bags. It is generally available from garden shops but can also be found at chemical supply stores. Some stores sell a premixed 16 percent citric acid solution, which would be an alternative for those who do not want to mix their own.

• 6

  Mix the spray by mixing 1.3 pounds of citric acid per 1 gallon of water. For average yards, a homeowner can use a pump sprayer/applicator. Pressure is created by using a hand pump and the spray is applied with a hand-held applicator. They are commonly available in 1 to 5 gallon capacities at most garden shops.

• 7

  Spray the citric acid solution on plants, including the undersides of leaves. If frogs start to jump out of the plants, you can spray them directly. Another application of the spray should be completed after two weeks, which would be the time it would take any eggs to hatch.

• 8

  Be aware that citric acid might damage some plants. It is a good idea to rinse the treated plants well with water. Do this about one hour after spraying. If there are sensitive plants or flowers in the area, it is advisable to take a small part of the plant and test the effects of citric acid on it prior to spraying a large number of plants.