How To Get Rid Of Frogs

Summary: Frogs are great insect eaters and are usually welcomed guests around ponds. But, sometimes too many frogs is too much of a good thing.

Gus; Yucaipa, CA asks:

We have frogs near a Koi pond that are making a racket. What can we do to get rid of them?

Dear Gus;

Frogs for the most part are beneficial animals eating lots of insects that might otherwise damage plants and vegetables. Unfortunately, frogs come with voices and they love to speak out during all hours of the night, crooning their frog-love-songs. Music to another frog. Unending noise to our ears.

There are lots of reasons the frogs are coming to the pond. The many varieties of insects hatching along the edges of the water make the pond a drive-up smorgasbord for any hungry frog. Of course, the water is a relaxing spa for many types of frogs. So, the decision is how to discourage the frogs from the water attraction. There are many avenues to explore.

Errecting a net screen to ward off bull frogs seems to be a popular idea. The net fence will have to be about two feet high and it will have to be buried into the ground about six inches to keep the frogs from going under. You can also install netting across the top of the pond, securing it around the edges. You can purchase UV resistant three-quarter inch netting from various bird netting suppliers such as Bird-B-Gone or Bird Barrier for about forty cents a square foot. The net allows plenty of air and sunlight through, but keeps out small animals, including frogs.

There are no pesticides labeled for frog control, but there are pesticides that can be applied to reduce the insect populations that the frogs are feeding on. Cypermethrin is a synthethic pyrethroid that can be applied with a hand sprayer. You should treat areas around lights, gutters, leaf litter and other areas likely to attract insects. Knock off the frog's food source and the frogs will have to go elsewhere for their meals.

Some people like to use snake repellents to discourage frogs. Most snake repellents contain some form of naphthalene or paradichlorobenzene, both used in moth balls. The odor is supposed to repel the target pest. Apply it in a band around the area to be protected, but keep it out of gardens and away from areas where it might leach into nearby water. Rain will melt the moth balls and if the melted chemical it makes it into the pond you will have dead fish the next morning, for sure.

Hawaii is fighting an epidemic of a fast-reproducing little frog that was inadvertently brought onto the island. The frog is threatening to endanger the fragile Hawaiian eco-system balance, so authorities have been searching for ways to stop its spread. Two methods that have shown some success and which are being tried under special experimental use permits are a  2-percent-caffeine solution, containing a far higher concentration of caffeine than that of regular coffee. The solution kills the frogs, but does little to surrounding insect populations. In addition to controlling frogs, the solution also does a nice job on garden slugs, the bane of the Hawaiian orchid industry.

Still another potential aid in the frog battle is citric acid, the primary constituent of lemon juice. Preliminary tests used a citric-acid formulation roughly comparable to double-strength lemon juice. The spray isn't quite as potent as caffeine for killing frogs. Hydrated lime, the powder used to reduce the acidity of soil, also kills frogs but cannot legally be used against frogs unless it were to receive federal approval as a pesticide.

A 3-minute spray of hot water (116°F) kills any coquies and greenhouse frogs present. As a bonus the treatment kills geckos, centipedes, and about everything else in the soil except ants. You would have to rent some type of hot water generator to get a consistent spray of that temperature.