How to Make and Use Pyrethrin Insecticide

What Pyrethrins Are and How They Work

By
Jon VanZile
Jon VanZile

Jon VanZile was a writer for The Spruce covering houseplants and indoor gardening for almost a decade. He is a professional writer whose articles on plants and horticulture have appeared in national and regional newspapers and magazines.

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Updated on 08/09/24
Reviewed by
Amanda Rose Newton
Amanda Rose Newton
Reviewed by Amanda Rose Newton

Amanda Rose Newton is a pest specialist and horticulture expert, reviewing pest control and gardening content for The Spruce's Cleaning and Gardening Review Board. Her passion for pest control and sustainable gardening allows her to review plant and pest content for best practices and accuracy. She is a board-certified entomologist and volunteers for USAIDs Farmer to Farmer program. She is a professor of Horticulture, an Education Specialist, and a pest specialist.

Learn more about The Spruce's Review Board
Person spraying pyrethrin pesticide onto a garden plant

The Spruce / Jayme Burrows

In This Article
Project Overview
  • Working Time: 1 - 2 hrs
  • Total Time: 3 wks
  • Skill Level: Intermediate
  • Estimated Cost: $0 to $20

Pyrethrin-based insecticides are a class of organic insecticides derived from natural substances found in a single species of flower in the Chrysanthemum genus (C. cinerariifolium), also known as Dalmatian daisy or pyrethrin daisy. Pyrethrin insecticides are effective against a wide variety of insects, including soft-bodied chewing and sucking insects such as aphids, leafhoppers, mealybugs, spider mites, stink bugs, scale, thrips, and whiteflies.

Many manufacturers market pyrethrin insecticides, but these solutions are often synthetic versions that have added chemicals. It is also possible to make your own effective—and genuinely organic—pyrethrin insecticide if you happen to grow Dalmatian daisies or have access to them.

What Is Pyrethrin?

The term "pyrethrin" refers to any of the six target plant molecules (esters) that are extracted from C. cinerariifolium to use as a natural organic pesticide. The combined extraction containing multiple pyrethrins is sometimes called "pyrethrum." Similar pesticides made by synthetic chemical processes, often including additives to make the pesticide more long-lasting, are known as "pyrethroid" pesticides. However, while pyrethrins are considered organic pesticides, pyrethroids are not.

Safety Considerations

Pyrethrin insecticides are biodegradable and will break down within a few days in direct sunlight. While effective against soft-bodied insects, the insecticide does not persist in the soil or on the crop, which is why it is relatively safe to use within a vegetable garden.

Pure pyrethrins have low toxicity to humans and pets. In fact, various shampoos that control head lice in humans and fleas in pets contain pyrethrin. That being said, they are not entirely harmless. Some people have skin sensitivity to these compounds, and oral consumption can lead to digestive distress. You should use proper caution when mixing and using pyrethrin insecticides.

Warning

Pyrethrins are toxic to fish and other aquatic life, so you should never use them around ponds or bog gardens, especially where runoff might reach natural streams.


Remember that pyrethrin is highly toxic to most insects. While it is an effective agent against pests, it can also be deadly to the beneficial insects that pollinate your garden and eat pests. It is not wise to broadcast spray pyrethrum on all your plants. Use the insecticide as a spot treatment only when and where you have a pest outbreak. 

When to Make and Use Pyrethrin Insecticide

When genuine organic pyrethrin insecticides are commercially available, it may be best to opt for those products since they have been refined under careful control and will produce predictable results. However, in some cases, the insecticide available for sale may be pyrethroids, which are not organic. So, if a true organic insecticide is your goal, making your own pyrethrin insecticide may be the best option.

Regarding application, it's best to regard any insecticide as a last resort, reaching for the spray only when plant damage becomes intolerable. Left alone, populations of garden pests often find their own equilibrium as predatory insects respond to the appearance of aphids or other damaging insects. But when a particular plant is suffering damage you can't tolerate, then an organic plant-based insecticide such as pyrethrin or neem oil is always a better choice than a synthetic chemical insecticide.

Before Getting Started

Pyrethrin-based insecticide can be made using ingredients you probably already have around your home and a few inexpensive extra items. You will also need a garden with some actively growing Chrysanthemum cinerariifolium plants. Not just any daisy will do, as only C. cinerariifolium contains the pyrethrins that make for an effective homemade insecticide. In the garden trade, this plant is usually marketed as Dalmatian daisy or pyrethrin daisy, and it may be sold according to its previous botanical name, Tanacetum cinerariifolium.

The Dalmatian daisy is a popular garden plant for cottage gardens or naturalized wildflower gardens in locations with relatively dry soil. These perennial daisies are hardy in USDA zones 4 to 10, so they can generally be found at most garden centers, especially those that specialize in wildflower selections.

If you don't have your own growing plants, you can also buy cut flowers from a floral shop. The Dalmatian daisy is a popular cut flower.

What You'll Need

Equipment / Tools

  • Airtight plastic container
  • Protective mask
  • Coffee grinder or mortar and pestle
  • Spray bottle

Materials

  • Dalmatian daisy flowers
  • Liquid dish soap
  • Cheesecloth
  • Cooking oil

Instructions

Materials needed to make pyrethrin pesticide

The Spruce / Jayme Burrows

  1. Gather and Dry the Flower Heads

    • Harvest flower heads during the Dalmatian daisy's active bloom season (early and midsummer).
    • Choose fully opened flowers to harvest. You need not worry about over-harvesting, as vigorous cutting only prompts additional flowering on these plants. An adequate amount of insecticide can be created with as few as 12 flower heads.
    • Place the harvested flower heads in a paper bag.
    • Hang the paper bag in a cool, dry, dark place to fully dry. The drying process can take a few weeks.
    Person harvesting daisies for use in homemade pesticide

    The Spruce / Jayme Burrows

  2. Store the Flower Heads

    • Transfer the dried flower heads to a tightly sealed, airtight container.
    • Place the container in a freezer. They will retain their effectiveness for up to six months if frozen.
    • Do not pulverize the flowers until you mix the insecticide.
    Transferring the flower heads to an air tight plastic container

    The Spruce / Jayme Burrows

  3. Make the Solution

    • Wear a mask when you are ready to make the pyrethrin insecticide.
    • Use a mortar and pestle or coffee grinder to pulverize enough flower heads to make 1 cup of fine powder. The powder must be pretty fine to enhance the extraction of the pyrethrins.
    • Add the finely ground powder to a quart of warm water and let the solution soak for three hours, stirring occasionally.

    Tip

    It is also possible to use the pulverized powder as insecticide dust without mixing it with water. This is an effective method for certain plants that don't react well to wet leaves, such as roses. You can also apply powder to the soil.

    Dry powders last up to six months if you put the crushed flowers in a sealed container and into the freezer.

    Using a mortar and pestle to grind the flower heads

    The Spruce / Jayme Burrows

  4. Strain the Solution

    • Strain the raw solution through cheesecloth to separate the pyrethrin-enhanced liquid from the pulverized flower parts. Using the raw solution without straining it will often clog a sprayer.
    • Mix thoroughly the strained liquid with a teaspoon each of liquid soap and cooking oil to enhance its ability to cling to plants.
    • Pour the solution into a clean spray bottle for application.

    Tip

    A homemade solution of pyrethrin insecticide has a shelf life of only 12 to 24 hours, so any leftovers after application will need to be discarded. Thus, it's best to grind and mix the insecticide in relatively small amounts as needed.

    Straining the solution through cheesecloth

    The Spruce / Jayme Burrows

  5. Spray the Insecticide

    • Use the solution as you would any commercial spray insecticide. The strength of homegrown pyrethrin varies, so experiment with the proportions until you achieve effective insect control.
    • Make sure to prevent pyrethrin sprays or powders from running off into ponds or water supplies, as pyrethrins are toxic to many forms of aquatic life.
    Spraying homemade pyrethrin pesticide onto a garden plant

    The Spruce / Jayme Burrows

FAQ
  • What are the disadvantages of pyrethrin?

    Pyrethrins are highly toxic to aquatic life, including fish and insects. In addition, they can negatively affect beneficial insects such as honeybees, reducing their motility and collapsing colonies. However, pyrethrins break down very quickly so the effects may be minimal.

  • How long does pyrethrin last on surfaces?

    Pyrethrin lasts one to two days before it begins to degrade.

  • How often can you spray pyrethrin?

    If you use a commercial spray, consult the label to find out the recommended usage. If you are using DIY pyrethrin, it usually has a short-term effect of one to two days so use it accordingly.

How to Use Neem Oil Spray as an Organic Insecticide
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Pyrethrins vs. Pyrethroids: What’s the difference? MGK/Sumitomo Fact Sheet.

  2. Pyrethrins General Fact Sheet. Oregon State University Extension Services.

  3. Less Toxic Insecticides. Clemson University.

  4. Home Preparation of Pyrethrum. McGill University Ecological Agriculture Projects.

  5. Pyrethrins General Fact Sheet. National Pesticide Information Center.

  6. Public Health Statement on Pyrethrins and Pyrethroids. Centers for Disease Control and Prevention (CDC).