Pyrethrin

Description

The six individual ester molecules extracted from natural pyrethrum insecticide derived from chrysanthemum flowers. The pyrethrin molecules are usually isolated and standardized for use in chemical formulations. They first appeared on markets in the 1900s and have been used in products such as bug bombs, insect sprays, and animal treatments. Pyrethrins alone do not usually kill the insects just make them are unconscious. Thus, they are often used in combination with other insecticides. The synthetically produced pyrethrin mixture is called permethrin.

Synonyms and Related Terms

pyrethrins; pyrethrum; pyrenone; pyrocide; permethrin

Risks

• Highly toxic to cats, fish and aquatic invertebrates
• Low toxicity to humans and birds
• Breaks down rapidly in sunlight within 12-24 hours
• Toxic by ingestion, inhalation and skin contact. LD50 = 584-900 mg/kg.
• Persons sensitive to ragweed will be prone to pyrethrin allergic reactions.

Physical and Chemical Properties

• Insoluble in water.
• Soluble in alcohol, petroleum ether, kerosene, carbon tetrachloride, ethylene dichloride, nitromethane.

Resources and Citations

• MuseumPests.net: Pesticide Database
• Wikipedia: Pyrethrin Accessed July 2023 and Nov 2026
• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 643
• Lynda A. Zycherman, J.Richard Schrock, A Guide to Museum Pest Control, FAIC and Association of Systematics Collections, Washington DC, 1988
• The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983
• Encyclopedia Britannica, http://www.britannica.com Comment: "pyrethrum" [Accessed March 26, 2002].
• J. Dawson, CCI Technical Bulletin, 'Solving Museum Insect Problems: Chemical Control' , Canadian Conservation Institute, Ottawa, No. 15
• Stephen R. Edwards, Bruce M. Bell, Mary Elizabeth King, Pest Control in Museums: a Status Report 1980, Association of Systematics Collections, Washington DC, 1980
• Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982