How Pyrethrins & Pyrethroids Work

Insect control products contain both “active” and “inert” ingredients

Botanical insecticides with pyrethrins as the active ingredient have relatively low mammalian toxicity1 and are extracted from pyrethrum daisies grown in Australia and Tanzania.

Active ingredients are what make insecticides work. Think of them as performing the same role as the engine in a car—providing the power for the insect control product. The role of insecticide active ingredients is to eliminate, control and repel insect pests. Though the names can get confusing, the process of getting to the pyrethrum daisy’s active ingredient for insecticide products is fairly straightforward.

How Do Pyrethrum and Pyrethrins Work?

Pyrethrum is the substance extracted from the flowers, while pyrethrins are the six active molecular “esters” within the extract that provide the insect-killing ingredients.

How Do Pyrethroids Work?

Pyrethroids are synthetically-derived active ingredients based on the molecular structure of natural pyrethrins but with different characteristics and insecticidal efficacy.

Other ingredients in insect control products are inert. They have limited or no insecticidal activity on their own, and include solvents, propellants, stabilizers, emulsifiers and fragrances. It’s these inert ingredients that support and maximize the effectiveness of active ingredients.

How Do the Active Ingredients in Insecticides Differ

  1. Toxicity level
    How toxic the active ingredient is to humans and animals.
  2. Residual life
    How long the active ingredient remains in the environment.
  3. Mode-of-action
    How the active ingredient works to eliminate or repel insects.
  4. Selective or non-selective
    Whether the active ingredient works on all problem insects or only a select few.
  5. Natural or synthetic
    Whether the insecticide active ingredient comes from nature or is man-made.

A Naturally Smarter Choice


Pyrethrum consists of six naturally occurring “esters,” called pyrethrins. These pyrethrins have low mammalian toxicity1, but are very effective on a wide variety of insects. They work by attacking the insects’ nervous system, both knocking them down and disrupting their metabolic defense systems.


The complex chemistry of the pyrethrin molecules, coupled with their biodegradability in sunlight2, can make it harder for insects to develop defenses against this insecticidal activity. In the case of many synthetic insecticides, insect populations can develop resistance, just like humans can with antibiotics, if they are over-exposed to the same one over time.


Sustainably grown and extracted in Australia and Tanzania, The Power of the Flower® is a biodegradable active ingredient with low mammalian toxicity1 and short environmental persistence2, making it the best choice for insect control in the most sensitive environments.

1Environmental Protection Agency – Toxicity Category III classification (40 CFR 156.62 Toxicity Category). Based on product data for Pyrethrins 50% TK containing Australian grown and extracted pyrethrins active ingredient.

2Pyrethrins General Fact Sheet. National Pesticide Information Center, November 2014, p 3.