Pyrethroids

Cypermethrin (CP) is a synthetic pyrethroid used as an insecticide in large-scale commercial agricultural applications as well as in consumer products for domestic purposes. It behaves as a fast-acting neurotoxin in insects. It is easily degraded on soil and plants but can be effective for weeks when applied to indoor inert surfaces. It is a non-systemic and non-volatile insecticide that acts by contact and ingestion, used in agriculture and in pest control products. Exposure to sunlight, water and oxygen will accelerate its decomposition. Cypermethrin is highly toxic to fish, bees and aquatic

300px|thumb|Chemical structure of allethrin isomers 300px|thumb|Chemical structure of permethrin isomers

Pyrethrum was a genus of several Old World plants now classified in either Chrysanthemum or Tanacetum which are cultivated as ornamentals for their showy flower heads. Pyrethrum continues to be used as a common name for plants formerly included in the genus Pyrethrum. Pyrethrum is also the name of a natural insecticide made from the dried flower heads of Chrysanthemum cinerariifolium and Chrysanthemum coccineum. The insecticidal compounds present in these species are pyrethrins.

Cyhalothrin (ISO common name) is an organic compound that, in specific isomeric forms, is used as a pesticide. It is a pyrethroid, a class of synthetic insecticides that mimic the structure and properties of the naturally occurring insecticide pyrethrin which is present in the flowers of Chrysanthemum cinerariifolium. Pyrethroids, such as cyhalothrin, are often preferred as an active ingredient in agricultural insecticides because they are more cost-effective and longer acting than natural pyrethrins. λ-and γ-cyhalothrin are now used to control insects and spider mites in crops including cotto

Cyfluthrin is a pyrethroid insecticide and common household pesticide. It is a complex organic compound and the commercial product is sold as a mixture of isomers. Like most pyrethroids (MoA 3a), it is highly toxic to fish and invertebrates, but it is far less toxic to humans. It is generally supplied as a 10–25% liquid concentrate for commercial use and is diluted prior to spraying onto agricultural crops and outbuildings.

Etofenprox is a pyrethroid derivative which is used as an insecticide. Mitsui Chemicals Agro Inc. is the main manufacturer of the chemical. It is also used as an ingredient in flea medication for cats and dogs.

thumb|right|300px|Allethrin I (R = −CH3)Allethrin II (R = −COOCH3) The allethrins are a group of related synthetic compounds used in insecticides. They are classified as pyrethroids, i.e. synthetic versions of pyrethrin, a chemical with insecticidal properties found naturally in Chrysanthemum flowers. They were first synthesized in the United States by Milton S. Schechter in 1949. Allethrin was the first pyrethroid.

Silafluofen is a fluorinated organosilicon pyrethroid insecticide.

Flumethrin is a pyrethroid insecticide and acaricide. It is used externally in veterinary medicine against parasitic insects and ticks on cattle, sheep, goats, horses, and dogs, and the treatment of parasitic mites in honeybee colonies.

Kadethrin is a synthetic pyrethroid with the chemical formula C23H24O4S which is used as an insecticide. It is the most potent knockdown pyrethroid (even stronger than pyrethrin II) but it is relatively unstable, especially when exposed to light (due to both the furan ring and the thiolactone group in the molecule).

Acrinathrin (Rufast and other trade names) is a pyrethroid insecticide and acaricide derived from hexafluoro-2-propanol. In beekeeping, it is used to control the mite Varroa jacobsoni, though resistance is developing.