What are Some Natural Insecticides?

J. Beam

Notwithstanding the desire and well-intentioned efforts of many organic gardeners, there comes a time when insecticides must be used to eliminate bugs that infest and destroy garden crops. Many prefer to use a natural insecticide rather than a synthetically produced chemical insecticide. Rotenone and pyrethrum are both very well known and widely used natural insecticides derived from plants. Other natural insecticides include nicotine, neem oil, and soap.

Oil derived from the neem tree is often used in natural insecticides.
Oil derived from the neem tree is often used in natural insecticides.

Rotenone and pyrethrum are commonly used as natural insecticides. Rotenone is derived from the root of tropical and sub-tropical plants of the genus Derris. Rotenone acts as a broad-spectrum natural insecticide that poisons both on contact and by ingestion. Rotenone is typically used as a dust or spray, and while non-toxic to plants, it is highly toxic to fish and moderately toxic to warm-blooded mammals.

Natural insecticides include soap.
Natural insecticides include soap.

Pyrethrum is derived from the Dalmatian chrysanthemum and is used in dust or liquid suspension form. In large concentrations, it acts as a natural insecticide by attacking an insect’s central nervous system. Pyrethrum in small concentrations may not be toxic to insects, but it retains the ability to repel insects. Pyrethrum is toxic to fish, but less toxic to mammals than synthetic pesticides. It is biodegradable and breaks down easily with exposure to light.

Some organic gardeners recommend using soap, which has been used as a natural insecticide for hundreds of years. Diluting liquid dishwashing detergent, such as Ivory, with water to a 1-2% solution that can be sprayed to cover plants has been found effective at controlling insects. However, use caution, as repeated and thorough coverage with high concentrations of soap may cause damage to certain kinds of plants. Soap as a natural insecticide may be far less toxic to humans and animals than other alternatives, but it can also be far less effective, especially when treating an infestation.

While nicotine, neem and other botanical insecticides not discussed here have been found to be effective with minimal to moderate success, any kind of natural insecticide should be used as minimally as possible. Just because you use a natural insecticide rather than a synthetic one does not mean it is any less harmful to animals or humans. Application of any type of natural insecticide should be performed safely and only at the frequency necessary to maintain a healthy crop of fruits or vegetables.

There are a variety of natural insecticides.
There are a variety of natural insecticides.

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Discussion Comments


I feel that natural pesticides and insecticides are an important part of keeping our earth green and healthy.

I know of one product that I have used, and it works well. It can be used for the home, farm, restaurant or the horticulture and agriculture industry.


Normally, insecticides work like a mild nerve agent that kills bugs but has little to no effect on humans. When the nerve agent is not properly diluted, however, it can cause excruciating pain and even death for humans. These kinds of sprays have been used in massive chemical warfare on civilians, and inadvertently using them on crops can have devastating results.


It seems that we are required to choose from the lesser of two evils here. There is insect life on the one hand, spoiling crops and causing hunger, and then there is insecticide use, which can also be dangerous. I think that using insecticides may be harmful, but it is necessary for economies and for food to flourish.


These kinds of insecticides can be particularly harmful if they are used in marine environments, because they contaminate the water and can quickly cause fish to wash up dead on the shore. This was the case in the Chesapeake bay, where insecticides from all around Maryland and surrounding states continue to leak into the bay and poison fish life. There are piles of dead and rotting fish on the shores there, and they stink for miles around.


Large scale efforts to reduce the insect population in the past have been devastating for humans and animal life. Mosquitos have involved defense mechanisms for many of these chemicals due to massive spraying, and certain people from certain regions have been maimed due to ingesting food that was sprayed by toxic chemicals or being exposed to it directly. In short, it is important to be careful what kind of insecticide you use, and to be sure to wash it off fully before distributing your produce.

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