Pyrethrum: A Natural Insecticide
1. Overview and Source
Pyrethrum is a natural insecticide derived from the dried, powdered flower heads of certain Chrysanthemum species, primarily Chrysanthemum cinerariifolium (also known as Tanacetum cinerariifolium). The active insecticidal compounds are called pyrethrins.
These flowers are native to the Balkans but are now cultivated in many regions with suitable climates, with major commercial production in Kenya, Tanzania, Rwanda, Ecuador, and Australia. The daisy-like flowers are harvested just as they begin to bloom, as this is when their pyrethrin content is highest.
2. The Active Ingredients: Pyrethrins
The powdered flowers contain six closely related insecticidal compounds, collectively known as pyrethrins:
Pyrethrin I
Pyrethrin II
Cinerin I
Cinerin II
Jasmolin I
Jasmolin II
These compounds work by targeting the nervous systems of insects, disrupting the sodium channels in nerve cells. This leads to rapid paralysis, a condition known as "knockdown effect," and is often followed by the death of the insect.
3. Key Characteristics and Advantages
Broad-Spectrum Efficacy: Effective against a wide range of insect pests including mosquitoes, flies, fleas, moths, and ants.
Rapid Action: Known for its fast "knockdown" effect, quickly disabling insects.
Low Mammalian Toxicity: Pyrethrins are among the least toxic insecticides to humans and other mammals when used properly, making them suitable for use in homes and on food crops.
Biodegradability: Pyrethrins break down quickly when exposed to sunlight, air, and moisture. This minimizes environmental persistence and residue problems.
Organic Certification: It is a cornerstone of organic farming and is approved by organic standards bodies worldwide (e.g., OMRI in the US).
4. Common Applications
Agriculture: Used on organic and conventional farms to protect fruits, vegetables, and stored grains from pests.
Public Health: A key ingredient in mosquito control products to combat vector-borne diseases like malaria and dengue fever.
Household Insecticides: Found in sprays, dusts, and mosquito coils for indoor and garden use.
Pet Care: Used in shampoos, sprays, and flea powders for dogs and cats (use must be carefully managed as cats are more sensitive).
Stored Product Protection: Protects grains and other stored commodities from insect infestation.
Post time:2025-10-20
