How to Make and Use Pyrethrin Pesticide

Pyrethrin-based insecticides are a class of organic insecticides derived from natural substances found in a single species of the Chyrsanthemum genus (C. cinerariifolium), also known as Dalmation daisy or pyrethrin daisy. Pyrethrin-based products are a very popular class of organic pesticides, since their nerve toxins are effective against many soft-bodied insects but have very low toxicity to humans and animals, including household pets such as cats and dogs. In fact, various shampoos that control head lice in humans and fleas in pets contain pyrethrins.

Many manufacturers market pyrethrin pesticides, but in many cases, these are synthetic versions that have added chemicals. But it is also possible to make your own effective—and genuinely organic—pyrethrin insecticide if you happen to grow Dalmation daisies or have access to them.

When to Make and Use Pyrethrin Insecticide

When genuine organic pyrethrin pesticides 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. But in some cases, the pesticides available for sale may be pyrethroids, which are NOT organic. So if a true organic pesticide is your goal, then making your own pyrethrin pesticide may be the best option.

As far as application goes, it's best to regard any pesticide 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 pesticide such as pyrethrin or neem oil is always a better choice than a synthetic chemical pesticide. 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.

Safety Considerations

Pyrethrin insecticides are biodegradable and will break down within a few days in direct sunlight. 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.

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.  

Pure pyrethrins have low toxicity to humans and pets, but 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 pesticides, as just because they are organic does not mean they are utterly harmless.

Before Getting Started

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

Dalmation daisy is a popular garden plant for cottage gardens or for naturalized wildflower gardens in locations with relatively dry soil. These perennial daisies are hardy in USDA zones 4 to 10, so it's generally possible to find them at most garden centers, especially those that specialize in wildflower selections.

If you don't have your own growing plants, it's also possible to buy cut flowers from a floral shop, as the Dalmatian daisy is a popular cut flower.