Organic Pest Control Series: Using Organic Pesticides

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When faced with a pest problem, gardeners often wish for a solution that comes in a spray bottle. It’s true that many poisons sold in garden centers will kill any, and often all, insects in your garden. But pesticides are hazardous to humans and wildlife, and most will kill beneficial insects along with the problem pests.

Even organic pesticides can kill beneficial insects, so they should be carefully used and only as a last resort. Learn about insect pests often seen in your area and their natural enemies, as well as cultural methods that keep populations low, before you decide to grow a food crop.

The organic pesticides described in these pages pose minimal harm to organisms you don’t want to harm, including humans. These products also are accepted under the National Organic Program Standards, which serves as a framework for certified-organic food production. In turn, the nonprofit Organic Materials Review Institute (OMRI) evaluates whether or not specific products comply with those standards. OMRI uses a panel of experts that includes farmers, scientists, environmentalists and businesspeople to decide which products should be approved for use by organic growers. Approved products usually display the OMRI seal on their label, or you can check OMRI to see whether a product is approved, restricted, or not allowed.

OMRI has two category codes for permissible products: “A” for allowed and “R” for restricted. Allowed products may be used freely at the grower’s discretion; most of them are soil amendments and organic fertilizers. Many organic pesticides carry a restricted code because they can harm beneficial insects and other wildlife, and thus should be used sparingly. Although all of the products listed here carry OMRI approval, many fall into the restricted category and should be used only when cultural controls have failed, and always according to label directions.

Two old-time natural pest control remedies, rotenone and sabadilla, are not included here because they are no longer commercially available and thus not likely to be used. Rotenone was once widely used by organic gardeners as the big guns brought out for tough insect pests such as Colorado potato beetles and cabbage worms. Made from the powdered seeds of jicama and other tropical vines, rotenone was a staple in garden dusts and pet flea powders. Rotenone is no longer approved for use on animals or in gardens, which is a good thing. A recent study has linked exposure to rotenone with a significant increase in Parkinson’s Disease in humans. The only current registered use for rotenone is as a fish-killing agent for targeted invasive species.

Sabadilla dust made from the dried seeds of a South American lily was once widely used by organic gardeners to control squash bugs, but it is also highly irritating to eyes and lungs, and is toxic to many beneficial insect species. No organic sabadilla products are currently available, and the only registered use for sabadilla products is to control sucking insects on citrus and mango.

Check out the other sections of our our Organic Pest Control Series: Beneficial Insects and Common Garden Pests.

Bt (Bacillus thuringiensis)

Learn how to use Bt (bacillus thuringiensis) products to kill harmful caterpillars and pests in your vegetable garden. Bt is one of the safest natural pesticides you can use to control caterpillar pests without harming beneficial insects.


Chickens may not be an organic pesticide, but they do devour any insect that moves, including grasshoppers, Colorado potato beetles, slugs and more. If you don’t trust chickens to roam among your vegetable and flower beds, feed them captured insects by hand.

Diatomaceous earth (DE)

Diatomaceous Earth (DE) products cut into insects’ bodies, causing them to die naturally of dehydration. When buying DE to use around your house, be sure to buy a product listed as “food grade.”

Horticultural oils

Horticultural oils are particularly useful in the organic orchard where they control pests that overwinter in bark crevices. The recommended practice for applying horticultural oils is to spray trees in spring, just before flower buds open.

Insecticidal soap

Learn how to use insecticidal soap to combat soft-bodied pests such as aphids, whiteflies and more. Under good storage conditions, insecticidal soap products may last five years or more.


Neem oil is a derivative of the Asian evergreen tree. A natural steroid, it causes insects to lose their appetite and lose interest in laying eggs.  Neem is best used preventively, before pests become a serious problem.


Organic pyrethrum spray paralyzes insects that come into contact with it and is the strongest insecticide allowed under National Organic Standards guidelines. Learn how to make, apply and store this potent organic pesticide.


The biological pesticide spinosad controls all types of caterpillars as well as Colorado potato beetle larvae and blister beetles. Learn how to apply and store this potent organic pesticide for effective organic pest control.

Spotted a Bug in Your Garden?

Tell us about it and you’ll be helping the Big Bug Hunt citizen science project.

Even More Articles About Organic Pesticides

Safe Homemade Natural Pesticides

If you want to rid your garden of many destructive insects without resorting to dangerous chemicals, here are a few suggestions for safe homemade natural pesticides.

Chickens in the Garden: Organic Pest Control

Look to your backyard flock for the best natural pest control around.

Using Milk as a Natural, Homemade Pesticide

Most people know the value of milk, but not many know that it is an essential ingredient in basic bug repellent. Learn how to put milk to use to keep your family bug-free.