Pyrethrum is a natural insecticide derived from the dried flower heads of certain species of chrysanthemum, primarily Chrysanthemum cinerariifolium (also known as Tanacetum cinerariifolium) . This perennial herb, which resembles a common daisy with white petals and a yellow center, is native to Eastern Europe and Asia but is now cultivated worldwide –5–9.

The active insecticidal components in pyrethrum are six chemical compounds collectively known as pyrethrins –5–10. These compounds are concentrated in the ovaries of the flower florets –9. Pyrethrum is widely recognized as one of the safest and most effective natural insecticides, particularly for use around food and in organic farming, due to its rapid degradation in the environment –1–6.

Key characteristics of pyrethrum include:

• Fast-acting: Provides quick "knockdown" and kill of a broad range of insects –2.

• Biodegradable: Breaks down rapidly in sunlight and air into harmless water and carbon dioxide, leaving no toxic residues –6.

• Low mammalian toxicity: It is of very low toxicity to humans and other mammals, making it safe for use in homes, restaurants, and organic farms –5–6.

• Non-synthetic origin: Because it is derived from a plant, pyrethrum is permitted for use in organic agriculture in many countries –10.

It is important to distinguish natural pyrethrum from synthetic pyrethroids. Pyrethroids are man-made chemicals developed to mimic the structure of pyrethrins but are more stable and persistent in the environment. They are generally more toxic to mammals and are not approved for organic production –5–10.