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.