Pyriproxyfen

Description

Pyriproxyfen is a pyridine compound and, in common with fenoxycarb, is a juvenile hormone mimic whose structure is unrelated to natural juvenile hormone. It is an insect growth regulator. Fleas absorb pyriproxyfen either by direct contact or by ingesting blood from a treated animal.

Description

Pyriproxyfen, like last week’s molecule, spinosyn A, is an insecticide. It is marketed in the United States under the trade names Distance and Nylar. Commonly used to combat fire ants, it is applied to the ground in a bait. Worker ants carry it to the colony, where it kills all of the ants, including the queen.

Description

Pyriproxyfen is a pyridine insecticide that mimics juvenile growth hormone, which prevents larvae from developing into reproduction-capable adults. The LD₅₀ of pyriproxyfen in rats is >5,000 mg/kg, >1,300 mg/cubic meter/4 hours, and >2,000 mg/kg through oral, inhalation, or percutaneous dosing, respectively. It is used as a larvicide in the drinking water of 11 municipalities in Brazil and rumors suggested it may be correlated with the increase in cases of microcephaly in Brazil. The acceptable daily intake determined by the World Health Organization is 0.3 mg/L. The prevalence of microcephaly in Brazil is not higher in municipalities that use pyriproxyfen in the water supply, compared with municipalities that use the larvicide Bti. In addition, in zebrafish, even very high doses (0.1 μg/ml, compared with 0.01 μg/ml used in practice for pest control) pyriproxyfen does not induce microcephaly or other brain malformations. Formulations containing pyriproxyfen are used for flea control in dogs and as an insecticide for ants.

Chemical properties

Gray to white crystalline solid or powder. Also described as a pale yellow, waxy solid or liquid. Commercial product is available as an emulsifiable concen- trate or wettable powders.

The Uses of Pyriproxyfen

Pyriproxyfen is a pyridine-based pesticide used against a variety of arthropoda, in particular to protect cotton crops against whitefly.

The Uses of Pyriproxyfen

Insecticide.

The Uses of Pyriproxyfen

Pyriproxyfen is used for control of public health pests (flies, beetles, midges, mosquitoes) by application to breeding sites.

What are the applications of Application

Pyriproxyfen is a larvicidal agent that mimics juvenile insect hormone

Definition

ChEBI: An aromatic ether that consists of propylene glycol having a 2-pyridyl group at the O-1 position and a 4-phenoxyphenyl group at the O-3 position.

Agricultural Uses

Insect growth regulator, Insecticide, Veterinary medicine: Pyriproxyfen is found in a number of household products as sprays, powders, baits, mists and shampoos for the control of fleas, ticks, mites and flying insects on pets, in the air, and in carpets and rugs. It’s a larvicidal agent that mimics juvenile insect hormone.

Trade name

ARCHER®; DALAR®; DISTANCE®; ESTEEM®; NYLAR®; S-9318®; S 31183®; SUMILARV® Pyriproxyfen

Potential Exposure

Pyriproxyfen is an unclassified insect growth regulator, insecticide, veterinary medicine found in a number of household products as sprays, powders, baits, mists and shampoos for the control of fleas, ticks, mites, and flying insects on pets, in the air, and in carpets and rugs. It’s a l larvicidal agent that mimics juvenile insect hormone.

Metabolic pathway

Pyriproxyfen is not persistent in soils and sediments and is rapidly metabolised by a variety of organisms. In rats and mice, the major metabolic pathways were hydroxylation of the aromatic ring, hydroxylation at the 5-position of the pyridyl ring, loss of the aromatic ring, cleavage of ether linkages and conjugation of the resultant phenols with glucuronic or sulfuric acid. The general pathways in soils, sediments and a variety of organisms involve fission of ether linkages and hydroxylation of the phenoxyphenol group.

Shipping

UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous haz- ardous material, Technical Name Required.

Degradation

[¹⁴C]Pyriproxyfen was dissolved in distilled water or sterile river water at a concentration of 0.2 mg kg^-1 and exposed to natural sunlight from November to December at 40°N latitude. The DT₅₀ values were 17.5 and 21 days in distilled water and sterile river water respectively. Photodegradation involved cleavage at the three ether linkages and the major products were carbon dioxide (11-29% of the applied radioactivity) and a product formed by loss of the phenoxyphenyl group (9) (16-30%). When [¹⁴C]pyriproxyfen was exposed to sunlight for 8 weeks on sandy loam and silty loam soils, the DT₅₀ values were 11 and 13 weeks respectively. Photodegradation involved cleavage at the three ether linkages to give products 4,6 and 10 but the major product was carbon dioxide, representing 9.5-13% of the applied radioactivity. Bound radioactivity accounted for 11-26% of the applied radioactivity at week 8 (Miyamoto et al., 1993). Degradation products are shown in Scheme 1.

Incompatibilities

This material is combustible. Dust may form an explosive mixture in air. Incompatible with oxidi- zers (chlorates, nitrates, peroxides, permanganates, perchlo- rates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.

Waste Disposal

It is the responsibility of chemical waste generators to determine the toxicity and physical properties and of a discarded chemical and to properly identify its classification and certification as a hazardous waste and to determine the disposal method. United States Environmental Protection Agency guidelines for the classification determination are listed in 40 CFR Parts 261.3. Additionally, waste generators must consult and follow all regional, national, state and local hazardous waste laws to ensure complete and accurate classification and disposal methods. Follow recommendations for the disposal of pesticides and pesticide containers. Containers must be disposed of properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.