Got Plant Pests? Try Insecticidal Soap

comments (1) August 30th, 2011

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ChrisMcLaughlin Chris McLaughlin, contributor
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Destroy aphids with insecticidal soap.
Photo by Newtonian under the Creative Commons Attribution License 2.0.
Send spittlebugs packing with some homemade insecticidal brew.
Photo by Mikeumo under the Creative Commons Attribution License 2.0.
You can purchase a commercial insecticidal soap or whip up your own homemade batch.
Destroy aphids with insecticidal soap.
Photo by Newtonian under the Creative Commons Attribution License 2.0.Click To Enlarge

Destroy aphids with insecticidal soap.


Photo by Newtonian under the Creative Commons Attribution License 2.0.

Backyard gardeners everywhere are doing their part to push pesticides out of the gardening picture for good and insecticidal soaps are helping them do just that. If you're battling soft-bodied pests such as aphids, whiteflies, mealybugs, soft scale, or spittlebugs, try showering them with insecticidal soap.

There are insecticidal soaps that have already been mixed and measured for you such as one made by Safer Brand. You'll find them at nurseries, online, or through garden catalogs. Commercial insecticidal soaps are considered eco-friendly, low-non toxic, and typically state that they can be used on both ornamental plants as well as edible ones (always double-check the label for guidance).

Some gardeners have their own favorite soap recipes, but whichever typr of insect brew you use, it's important to understand that using soap mixtures control pests after they've already arrived on the plant. Insecticidal soaps aren't preventive measures -- they're mant to kill the bugs that are already bugging you. Of course, there are homemade spray recipes that are made with ingredients such as hot pepper and garlic that are used on plants as a repellent as opposed to a killing agent. But that's a horse of a different color.

Homemade Insecticidal Soap

A simple mixture of 3 to 5 tablespoons of liquid dish soap (not detergent) and a bit of vegetable oil to a gallon of water works just as well. The trick here is that you want to use a dishwashing soap that doesn't contain a degreaser or you may kill more plants by burning their leaves than you do pests. This concoction is then poured into a hand-held spray bottle or garden sprayer and use it on their plants when the sun is low and temperatures are cool (usually the morning hours).

Depending on the soap recipe and the pest, they either coat the critter causing the insect's cells to collapse, affect their nervous system, or simply become immobilized (therefore easy to spray off with the hose). Once the soap has dried, it's no longer effective.

Don't forget that it's best to try a small test spot on plant leaves before spraying an entire plant with any soaps. Most do just fine, but a few may be adversely affected. Signs that plants aren't reacting well are spots on the leaves or brown edges or tips.

Nontoxic, Low-Toxic, or What?

Insecticidal soaps are placed in the very low-toxic category. In fact, many people claim that Safer brand is nontoxic to people and pets, as well as safe for beneficial insects. I think that for the most part that's true -- it's virtuously harmless to mammals although soaps can be slightly irritating to the eyes or skin. But the other school-of-thought is that anything that kills anything can't be considered entirely nontoxic.

While insecticidal soap may be considered safe for families and pets, there's a good chance it may take some of the beneficial insects down, too. So, a good rule of thumb is to use the soap only on the plants that have been invaded with pests and to read commercial labels carefully while applying. As an organic gardener, I think this is a terrific alternative to many other pest control methods.

posted in: insecticidal soap, homemade insecticidal spray

Comments (1)

Delolds writes: I recommend using castile soap (made with olive oil). I use Dr. Bonner's Mint. Mix 1 teaspoon with 1 quart water. Works great!
Posted: 1:17 pm on September 1st
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