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Pyriproxyfen

Pyriproxyfen is a synthetic pyridine-based insect growth regulator that functions as a juvenile hormone analog, interfering with the maturation and reproductive processes of immature arthropods such as fleas, mosquitoes, cockroaches, and various agricultural pests.^[1]^[2] Registered by the United States Environmental Protection Agency in 1995, it is formulated into over 300 products including sprays, granules, and pet treatments for use in residential, agricultural, and public health settings to suppress pest populations without broadly killing adult insects.^[1] Its molecular formula is C₂₀H₁₉NO₃, and it exhibits a half-life of 6.8 to 16 days in soil under sunlight exposure, binding strongly to soil particles and posing low risk of groundwater contamination.^[2]^[1] Pyriproxyfen demonstrates low acute toxicity to mammals, with oral LD₅₀ values exceeding 5000 mg/kg in rats, and is not classified as carcinogenic or genotoxic by regulatory assessments; however, high-dose studies in mice have reported testicular abnormalities and reduced body weights, indicating potential reproductive effects at elevated exposures.^[1]^[3] The World Health Organization endorses its use as a mosquito larvicide in drinking-water sources at concentrations up to 0.01 mg/L, where human exposure remains well below the acceptable daily intake of 0–0.1 mg/kg body weight, supporting its role in vector control for diseases like dengue.^[4]

Chemical Properties

Molecular Structure and Formula

Pyriproxyfen is an organic compound classified as a pyridine ether derivative, with the molecular formula C₂₀H₁₉NO₃ and a molecular weight of 321.37 g/mol.^[2] Its IUPAC name is 2-[1-(4-phenoxyphenoxy)propan-2-yloxy]pyridine, reflecting a core structure consisting of a pyridine ring connected via an oxygen atom to a branched propyl chain, which is further linked by another ether bridge to a 4-phenoxyphenyl moiety.^[2] This arrangement includes two ether linkages and an aromatic pyridine ring, characteristic of its chemical class.^[2] The compound was originally synthesized by researchers at Sumitomo Chemical Company as part of efforts to develop insect growth regulators.^[5] The precise stereochemistry at the chiral center in the propyl chain is typically a racemic mixture in commercial formulations, denoted as (RS).^[4]

Physical Characteristics and Stability

Pyriproxyfen is a colorless crystalline solid.^[6] Its melting point ranges from 48.0 to 50.0 °C.^[7] The compound exhibits low solubility in water, measuring 0.367 ± 0.004 mg/L at 25 ± 1 °C, which limits its mobility in aqueous environments.^[7] In contrast, it demonstrates high solubility in various organic solvents at 20 °C, including >150 g/100 g in acetone, acetonitrile, and methylene chloride; 6.97 g/100 g in hexane; 5.56 g/100 g in methanol; and 6.85 g/100 g in n-octanol.^[7] Pyriproxyfen remains stable under hydrolytic conditions across pH 4.0–9.0, with half-lives exceeding 200 days at 25–50 °C in buffered aqueous solutions.^[7] Photodegradation occurs readily in aqueous media under artificial sunlight or xenon lamp irradiation, yielding half-lives of 3.7 days (pyridyl-labeled) to 6.4 days (phenyl-labeled) in sterile pH 7 buffer.^[7] In aerobic water-sediment systems, degradation half-lives range from 16 to 21 days, driven by microbial activity and photolysis.^[7] On soil surfaces, aerobic microbial metabolism predominates, with half-lives of 3.5–28 days depending on soil type, depth, and conditions, while direct photodegradation proceeds slowly at 10–20 weeks.^[7]^[8]

Mechanism of Action

Juvenile Hormone Mimicry

Pyriproxyfen exerts its effects by mimicking juvenile hormone III (JH III), the predominant sesquiterpenoid hormone regulating insect development and reproduction, through agonistic binding to the insect-specific JH receptor.^[9] The primary receptor component is Methoprene-tolerant (Met), a basic helix-loop-helix-Per-Arnt-Sim (bHLH-PAS) transcription factor that, upon ligand binding, heterodimerizes with Taiman (Tai) to activate downstream transcriptional targets.^[10] This agonism sustains transcriptional repression of genes involved in the ecdysone biosynthetic pathway, such as those in the prothoracic glands, thereby inhibiting the pulsatile release of 20-hydroxyecdysone (20E), the active molting hormone.^[11] In the absence of pyriproxyfen, declining endogenous JH levels during the final larval instar permit 20E surges that trigger metamorphic gene cascades; pyriproxyfen's persistent receptor activation disrupts this temporal coordination, blocking the transition from juvenile to reproductive stages.^[12] This receptor-mediated mimicry manifests in disrupted molting and metamorphosis, where affected insects retain larval or pupal morphological traits, such as underdeveloped gonads or incomplete cuticle sclerotization, often culminating in lethality or reproductive sterility.^[13] For instance, in larval exposure, pyriproxyfen induces supernumerary molts or pupal-adult intermediates incapable of eclosion, while in imaginal stages, it suppresses vitellogenesis and oogenesis, yielding adults that deposit inviable eggs due to chorion defects or embryonic arrest.^[14] These outcomes stem directly from the agonist's interference with JH titer-dependent competence windows, where sustained signaling overrides the competence for 20E-induced adult differentiation.^[15] Pyriproxyfen's selectivity arises from the arthropod-exclusive nature of the Met-Tai receptor complex and JH signaling cascade, which lack structural or functional homologs in vertebrates; mammalian nuclear receptors, such as those for steroid hormones, exhibit no significant affinity for pyriproxyfen, precluding analogous endocrine disruption.^[16] Binding specificity is further tuned by species variations in Met ligand pockets, enabling targeted efficacy against dipterans and lepidopterans while sparing beneficial hymenopterans at field doses.^[17] This biochemical orthogonality underpins pyriproxyfen's role as a precise insect growth regulator, distinct from broad-spectrum neurotoxins.^[18]

Effects on Insect Development

Pyriproxyfen functions as a synthetic analogue of juvenile hormone (JH), which in insects regulates molting and metamorphosis by maintaining larval characteristics when levels are elevated. Exposure during immature stages disrupts the precise hormonal orchestration between JH and ecdysone, the molting hormone; specifically, it prevents the natural decline in JH titer necessary for pupation and adult differentiation, resulting in developmental stasis or aberration. In laboratory assays on species such as the citrus swallowtail (Papilio demoleus), application to late-instar larvae sharply curtailed pupation rates, with only 40% success at doses of 60 μg compared to 100% in untreated controls, as larvae remained trapped in prolonged pre-pupal phases or exhibited incomplete ecdysis.^[19] Similarly, in Drosophila melanogaster, pyriproxyfen prolonged pupal duration and elevated ecdysteroid levels in pupal extracts, confirming interference with metamorphic hormone signaling.^[20] Ovicidal action manifests through inhibition of chorion formation and embryonic morphogenesis, where pyriproxyfen penetrates the eggshell to mimic persistent JH signaling, arresting cell division and organogenesis prior to hatch. Studies on Aedes mosquitoes demonstrate that direct oviposition into treated substrates yields abnormal embryonic development, with hatching suppressed due to disrupted cuticular deposition and vitelline membrane integrity.^[21] Larvicidal effects predominate in early to mid-instars, halting ecdysis cycles and inducing supernumerary molts—extra larval instars without progression—while late-instar exposure blocks pupal commitment, producing non-viable pupae that fail to eclose or yield sterile, malformed adults incapable of reproduction.^[22] In whitefly (Bemisia tabaci) embryogenesis assays, pyriproxyfen potently suppressed adult emergence by derailing germline maturation, underscoring its targeted disruption of reproductive diapause transitions.^[23] Notably, pyriproxyfen exhibits negligible acute toxicity to mature adult insects, as post-metamorphic stages lack sensitivity to JH modulation, thereby sparing pollinators and predators in integrated pest management schemes. This stage-specificity arises from the compound's inability to penetrate adult cuticles effectively or override established metamorphic commitments, allowing beneficial insects like honeybees to complete development when exposed only as adults. Laboratory toxicological profiles confirm no direct lethality or fecundity impairment in emerged adults of target pests, contrasting with its profound interference in pre-imaginal phases.^[24]^[25]

History and Development

Discovery and Initial Research

Pyriproxyfen, chemically known as 2-[1-methyl-2-(4-phenoxyphenoxy)ethoxy]pyridine, was synthesized and developed by Sumitomo Chemical Co., Ltd., as part of research programs focused on juvenile hormone analogs for insect growth regulation.^[26] The compound, initially designated by the development code S-31183, emerged from systematic screening of pyridine-based structures designed to mimic endogenous insect hormones, targeting disruption of metamorphosis in immature stages.^[27] This approach prioritized empirical bioassays to validate causal interference with ecdysteroid-regulated development, distinguishing candidates by their potency against target pests like whiteflies and fleas while minimizing effects on non-target organisms.^[28] Initial laboratory evaluations in the late 1980s confirmed pyriproxyfen's selectivity and mode of action. For instance, studies by Loh and Yap in 1989 tested S-31183 against Aedes aegypti larvae, revealing sublethal concentrations that inhibited pupation and adult emergence without direct lethality, thus establishing its regulator profile through dose-response assays.^[29] Parallel tests demonstrated efficacy against scale insects and fleas, with applications disrupting egg hatching and larval viability via prolonged juvenile retention.^[28] These findings relied on controlled rearing experiments quantifying developmental arrest, providing causal evidence of hormone mimicry over broad-spectrum toxicity. Pre-commercial assessments in the same period highlighted pyriproxyfen's favorable safety margin, with acute toxicity tests showing LD50 values exceeding 5,000 mg/kg in rodents, far higher than effective insecticidal doses, which supported its advancement toward regulatory scrutiny.^[3] This low vertebrate impact, validated through standard OECD guidelines adapted for early screening, contrasted with higher-risk alternatives and underscored the compound's specificity derived from structural optimization in Sumitomo's programs.^[2]

Commercial Registration and Milestones

Pyriproxyfen was first registered in Japan in 1991 for controlling public health pests, including mosquitoes.^[30] The compound received its initial U.S. Environmental Protection Agency (EPA) registration for a product in 1995, marking the start of commercial availability in agricultural and pest control applications.^[31] By 1996, it had been introduced in the United States for protecting cotton crops from whiteflies, with subsequent expansions to structural and pet flea control products under trademarks like Nylar.^[32] Regulatory approvals broadened in the 2000s to include mosquito larvicide uses, supported by data on its low environmental persistence and selectivity for insects.^[33] The World Health Organization (WHO) assessed pyriproxyfen for safe application as a larvicide in drinking-water sources and containers, recommending its use at dosages up to 0.01 mg/L for dengue vector control due to minimal health risks at those levels.^[4] This endorsement facilitated integration into public health programs, including trials in Brazil's National Dengue Control Program, where it has been deployed since the mid-2010s to target Aedes aegypti breeding sites amid rising Zika and dengue outbreaks.^[34] Adoption milestones include its listing in WHO guidelines for potable water treatment against mosquito vectors, affirming its role in integrated vector management without significant impacts on water quality or non-target organisms.^[35] In Brazil, large-scale interventions, such as dissemination stations in Amazonas state, demonstrated population suppression effects by 2024, building on earlier efficacy against immature mosquito stages.^[36] Recent formulation advances, including pyriproxyfen-loaded nanoemulsions developed in 2021, have enhanced dispersion, insecticidal potency against houseflies, and ecological safety by reducing required dosages and mammalian toxicity compared to emulsifiable concentrates.^[37] These innovations support ongoing registrations for refined delivery in vector and agricultural settings.^[38]

Applications and Uses

Agricultural Pest Control

Pyriproxyfen is employed in crop protection primarily against immature stages of hemipteran pests, including whiteflies (Bemisia tabaci), aphids, and scales, on field crops such as cotton and fruit trees like citrus.^[39] In cotton production, it targets sucking pests by disrupting nymphal development, with field applications demonstrating significant reductions in whitefly populations at rates of 200 g active ingredient per hectare, leading to improved seed cotton yields of up to 19.43 quintals per hectare.^[40] For citrus, it controls scales such as the cottony cushion scale, applied during periods of pest vulnerability to minimize interference with bloom-stage crop growth.^[39]^[41] Formulations are typically delivered as emulsifiable concentrates or water-dispersible suspensions via foliar sprays, allowing low-dose applications that target juvenile hormone regulation without affecting adult insects or neurotoxic pathways common in alternatives like pyrethroids.^[42] This mode of action supports its integration into pest management programs by delaying resistance development in populations of pests like the sweetpotato whitefly, as evidenced by sustained efficacy in long-term field monitoring.^[43] Such strategies promote sustainable yields through rotation with other control methods, reducing overall insecticide reliance on high-volume neurotoxins.^[42] Economic benefits stem from efficient use rates, often 50-200 g active ingredient per hectare, which lower input costs compared to broader-spectrum insecticides while preserving beneficial predators in orchard and row crop systems.^[40] In Bt cotton trials, pyriproxyfen treatments have shown superior performance against nymphal whiteflies at multiple doses post-application, outperforming untreated controls without inducing phytotoxicity.^[44]

Vector Control in Public Health

Pyriproxyfen serves as a larvicide in public health vector control strategies, primarily targeting Aedes aegypti mosquitoes that transmit dengue, Zika, and chikungunya in urban settings. It is applied to larval habitats such as water storage containers and domestic breeding sites at dosages up to 0.01 mg/L, where it inhibits eclosion by mimicking juvenile hormone and disrupting metamorphosis, thereby preventing adult emergence without affecting non-target aquatic organisms at operational levels.^[4]^[45] Laboratory and field trials consistently show 80-100% inhibition of adult mosquito emergence from treated larvae and pupae. For example, granule formulations achieved 100% inhibition for approximately 50 weeks in container simulations, while controlled-release products sustained >87% emergence inhibition for six months in water storage scenarios.^[46]^[47]^[48] This efficacy extends to integrated vector management (IVM) programs, where pyriproxyfen reduces immature Aedes densities by targeting oviposition sites and preventing reproductive cycles.^[49] The World Health Organization endorses pyriproxyfen for larval control in drinking-water containers and other potable sources as part of IVM, citing its low mammalian toxicity and environmental persistence under field conditions. In Brazil, it was integrated into national campaigns starting in 2014 for dengue suppression and scaled up during the 2015-2016 Zika epidemic, with applications in northeastern states reaching water storage in households to curb vector proliferation amid outbreaks.^[50]^[51] Large-scale pragmatic trials, such as those in Belo Horizonte using mosquito-disseminated formulations, have evaluated its impact on transmission dynamics, demonstrating sustained larval suppression over months.^[52]^[53]

Veterinary and Household Uses

Pyriproxyfen is incorporated into topical spot-on treatments, collars, and sprays for flea control on dogs and cats, targeting the larval and egg stages of Ctenocephalides felis by mimicking juvenile hormone and inhibiting development into adults.^[54]^[55] Products such as Vectra, containing dinotefuran combined with pyriproxyfen, are applied monthly to dogs over 8 weeks old, repelling and killing fleas while preventing egg hatch for extended periods.^[55] Impregnated collars with pyriproxyfen achieve nearly 100% inhibition of flea egg hatching for up to 6 months, disrupting off-host life stages in pet environments.^[56] In veterinary applications, pyriproxyfen does not kill adult fleas but sterilizes females and blocks immature stages, with exposure concentrations as low as 0.01 mg/L in blood or 0.0001 mg/kg on cat hair preventing egg development.^[9] Field evaluations show over 95% efficacy in halting egg hatching for 13 weeks at higher concentrations, making it suitable for integrated flea management in companion animals.^[32] These formulations are EPA-registered for direct pet application, emphasizing safety for mammals due to low toxicity and targeted insect specificity.^[1] For household use, pyriproxyfen features in indoor sprays and foggers against cockroaches, ants, and fleas, with formulations like 10% emulsifiable concentrates providing control of nymphs and eggs for up to 6 months post-application.^[42] These products, often low-odor and non-staining, target pests in cracks, carpets, and pet bedding without requiring professional equipment, and are registered for residential ant and roach baits or barriers.^[57] EPA approvals cover over 100 consumer products for home flea and tick control in pet quarters, facilitating non-professional use through ready-to-use aerosols and granules.^[1]^[57]

Efficacy Data

Field Trials Against Mosquitoes

Field trials of pyriproxyfen against Aedes mosquitoes, primary vectors of dengue and Zika, have demonstrated high efficacy in inhibiting adult emergence from treated breeding sites. Granular formulations applied at concentrations of 1–10 ppm (mg/L) achieved 90–100% inhibition of emergence (IE) for up to 90 days in various settings, including urban and peri-urban areas in Malaysia and Australia.^[58] These results reflect sustained disruption of larval-pupal development without rapid degradation, outperforming shorter-duration larvicides in persistent water bodies.^[58] In urban population suppression trials, mosquito-disseminated pyriproxyfen via autodissemination stations yielded extensive coverage and marked reductions in juvenile stages. A neighborhood-scale study in Iquitos, Peru, reported up to 100% dwelling coverage and 94.3% of sentinel breeding sites contaminated, boosting juvenile mortality from a baseline of ~4% to ~75% within months.^[59] This translated to over a 10-fold decrease in adult emergence, from 1,000–3,000 individuals per month pre-intervention to ~100 per month during the 4-month treatment period in December 2011–March 2012.^[59] Similar autodissemination approaches in other trials reduced adult emergence by 42–98%, with effects lasting 8–12 weeks.^[58] Pyriproxyfen integrates effectively with sterile insect techniques (SIT), forming boosted SIT (BSIT) variants that enhance sterilization of wild females through contaminated sterile males, amplifying population suppression while minimizing resistance risks due to its non-lethal, developmental mode of action.^[46] Field evaluations of such combinations have shown prolonged efficacy beyond conventional SIT alone, particularly in tropical environments with continuous mosquito breeding.^[46] No widespread resistance has emerged in monitored Aedes populations under these regimens.^[58]

Effectiveness on Other Insect Pests

Pyriproxyfen exhibits high efficacy against California red scale (Aonidiella aurantii) nymphs, causing significant mortality in early developmental stages. Laboratory assays conducted in 2007 demonstrated mortality rates of 86% at 0.2 mg active ingredient per liter and 100% at 0.4 mg/L when applied to developing stages.^[60] These effects stem from the compound's disruption of juvenile hormone signaling, preventing successful molting and embryogenesis in treated females.^[61] Field applications targeting small nymphs further support its role in scale control, though resistance has emerged in some California populations since the 2020s. In veterinary and household settings, pyriproxyfen effectively controls cat fleas (Ctenocephalides felis), primarily through inhibition of egg hatching and adult emergence. Studies show egg-laying inhibition exceeding 92% for up to 29 days post-treatment, with adult emergence reduced by 99.8% over eight weeks in combined formulations.^[63] Field trials confirm sustained efficacy beyond 30 days, with treated animals producing no viable eggs from day 8 through 30 and overall production reduced by at least 95.8% in subsequent infestations.^[64] This mode of action targets immature stages without broadly affecting adult fleas, making it suitable for long-term environmental control in infested homes.^[65] Pyriproxyfen integrates well into pest management by sparing many non-target predators, thereby preserving natural enemy populations and mitigating secondary outbreaks. Its low toxicity to adult beneficial insects, such as honeybees and predatory lacewings, supports selective use in programs emphasizing biological control.^[66] Empirical observations in cotton systems indicate compatibility with generalist predators when applied judiciously, enhancing overall sustainability compared to broad-spectrum alternatives.^[67] However, sublethal effects on certain predators, like altered cocoon formation in lacewings, underscore the need for application timing to minimize unintended impacts.^[68]

Comparative Advantages Over Alternatives

Pyriproxyfen offers distinct advantages over traditional organophosphate insecticides, such as temephos, primarily through its targeted mode of action as a juvenile hormone mimic that inhibits metamorphosis in immature insects without affecting the nervous system, thereby reducing the likelihood of cross-resistance development seen in neurotoxic agents where enzyme mutations confer broad tolerance.^[46] Organophosphates have faced escalating resistance in vector populations due to overuse, whereas pyriproxyfen's specificity delays resistance onset, as evidenced by sustained efficacy in field applications against Aedes aegypti even in areas with resistant strains to conventional larvicides.^[69] In terms of application efficiency, pyriproxyfen achieves near-complete inhibition of adult mosquito emergence at concentrations as low as 0.012 ppb in bioassays, representing orders of magnitude less material than typically required for organophosphates (e.g., temephos LC50 values often exceeding 100 ppb in susceptible strains), which translates to 10-100 times reduced dosage needs and minimized environmental loading.^[50] ^[70] This selectivity extends to non-target pollinators; pyriproxyfen demonstrates low acute toxicity to adult honey bees, with 48-hour LD50 values far exceeding field exposure levels, resulting in negligible mortality compared to broad-spectrum alternatives that harm beneficial insects.^[16]^[71] From a cost-efficacy perspective, integration of pyriproxyfen in dengue vector management yields substantial savings by enabling reduced overall pesticide volumes—often fractions of broad-spectrum regimens—while maintaining control, as combinations with synergists like spinosad rationalize applications and cut financial outlays in integrated vector management programs.^[72] Recent analyses underscore its superior safety-efficacy balance in sustainable pest control, positioning it as a preferable option for long-term programs where minimizing non-target impacts and resistance pressure is paramount.

Toxicology and Safety Profile

Toxicity to Mammals and Humans

Pyriproxyfen demonstrates low acute toxicity to mammals through multiple exposure routes. In rats, the acute oral LD₅₀ exceeds 5,000 mg/kg body weight for both males and females, indicating minimal risk of lethality even at high doses.^[74] This value aligns with the U.S. Environmental Protection Agency's (EPA) Toxicity Category IV classification for practical non-toxicity via the oral route. Dermal LD₅₀ values in rabbits also surpass 2,000 mg/kg, with no skin irritation or sensitization observed, further underscoring its low mammalian hazard profile. Inhalation studies in rats show an LC₅₀ greater than 2.06 mg/L, confirming negligible respiratory toxicity.^[1] Chronic and subchronic exposure studies in rodents reveal no carcinogenic potential or genotoxic effects. Long-term dietary administration to rats and mice at doses up to 140 mg/kg/day and 420 mg/kg/day, respectively, produced no tumors or mutagenic activity, leading the EPA to classify pyriproxyfen as "Group E" (evidence of non-carcinogenicity for humans). Genotoxicity assays, including Ames tests and in vivo micronucleus evaluations, consistently tested negative. Hepatocellular hypertrophy and renal tubular changes occurred in rats only at doses above 100 mg/kg/day, with no-observed-adverse-effect levels (NOAELs) established at lower thresholds such as 10 mg/kg/day in 2-year studies. These effects were reversible and linked to metabolic overload rather than inherent toxicity.^[75]^[76] In humans, pyriproxyfen poses low risk due to limited absorption, rapid metabolism, and efficient excretion. Oral absorption in rats is approximately 40-50%, primarily via hydroxylation of the phenoxyphenyl ring followed by ether bond cleavage and conjugation, yielding non-toxic metabolites excreted mainly in feces within 48 hours. Human exposure incidents are rare, with the National Pesticide Information Center reporting no severe dermal or oral poisonings; mild eye irritation may occur but resolves quickly without systemic effects. Occupational and residential exposure assessments confirm margins of safety exceeding 100-fold for typical application rates.^[77]^[1]^[78]

Environmental Fate and Non-Target Impacts

Pyriproxyfen undergoes aerobic degradation in soil with a half-life of 6.4 to 36 days, depending on environmental conditions such as microbial activity and temperature. Photodegradation in soil occurs more slowly, with half-lives of 10 to 20 weeks influenced by soil type and light exposure. Its octanol-water partition coefficient (log K_ow) of 5.37 suggests potential for bioaccumulation in lipid-rich tissues, with an estimated bioconcentration factor (BCF) of 1620 in fish; however, rapid metabolism and excretion in exposed organisms limit actual accumulation and long-term persistence in the environment.^[4]^[8]^[2] In aquatic systems, pyriproxyfen poses selective risks primarily to non-target invertebrates rather than vertebrates. It exhibits high toxicity to Daphnia magna, inducing reproductive impairments and occasional mortality at concentrations as low as parts per billion detected in treated waters. Crustaceans and aquatic insect larvae show sensitivity, though effects such as disrupted development are often reversible upon cessation of exposure. In contrast, acute toxicity to fish and birds remains low, with no direct impacts anticipated at field application rates.^[79]^[80] Field monitoring data indicate minimal environmental residues post-application, with maximum pyriproxyfen concentrations of 1.34 μg/L observed in non-targeted surface waters, typically dissipating rapidly due to hydrolysis and photolysis. These low persistence levels and targeted delivery methods, such as in integrated vector management, mitigate broader ecosystem disruptions while addressing pest populations effectively.^[81]^[82]

Exposure Assessments and Risk Mitigation

The acceptable daily intake (ADI) for pyriproxyfen is 0.1 mg/kg body weight per day, established by the Joint FAO/WHO Meeting on Pesticide Residues based on a no-observed-adverse-effect level (NOAEL) of 10 mg/kg body weight per day from long-term studies in rats, applying a 100-fold uncertainty factor.^[78] Dietary exposure assessments by the European Food Safety Authority (EFSA) and the U.S. Environmental Protection Agency (EPA) consistently show chronic intakes from residues in crops such as fruits, vegetables, and grains to be negligible, typically representing less than 1-5% of the ADI for the general population, with higher percentiles (e.g., 99th) remaining below 10% even in high-consumption scenarios.^[83] ^[57] Drinking water exposures are similarly minimal, with EPA human health benchmarks for pesticides indicating pyriproxyfen concentrations in groundwater and surface water rarely exceed levels posing aggregate risk when combined with food residues, due to its moderate persistence and low mobility in soil.^[84] Quantitative risk models, such as those employed by EFSA using the EFSA PRIMo model for chronic dietary risk, incorporate probabilistic distributions of residue levels from field trials and consumption data, demonstrating margins of exposure exceeding 1,000-fold relative to toxicological endpoints, thereby affirming low probabilistic risk under realistic low-exposure conditions.^[85] For vector control applications, such as auto-dissemination stations targeting Aedes mosquitoes, exposure modeling accounts for indirect human contact via contaminated surfaces or water, predicting dermal and inhalation doses orders of magnitude below reference doses, with auto-dissemination inherently limiting dissemination to gravid females and reducing non-target drift.^[86] Practical safeguards include mandatory no-spray buffer zones of 5-30 meters adjacent to aquatic habitats or sensitive crops during aerial or orchard applications, as specified in EU peer reviews, to attenuate spray drift and surface runoff, thereby minimizing unintended exposures to humans and wildlife.^[77] Post-application monitoring in agricultural and public health settings, including residue surveillance in Brazil and Southeast Asia following widespread use, has yielded no empirical evidence of chronic effects such as endocrine disruption or developmental anomalies in exposed populations, aligning with causal expectations from sub-threshold dosing in mammalian toxicology data.^[87] ^[75]

Controversies and Debunked Claims

Alleged Link to Microcephaly in Brazil

In February 2016, a report circulated by an Argentine physicians' group alleged that pyriproxyfen, a larvicide added to drinking water reservoirs in parts of Brazil starting in 2014 to control Aedes aegypti mosquito larvae, was responsible for the spike in microcephaly cases observed during the 2015-2016 Zika outbreak, rather than the virus itself.^[88] The claim referenced pyriproxyfen's juvenile hormone-mimicking action in insects and cited extrapolations from high-dose rodent studies showing developmental effects, but provided no mechanistic evidence, dose-response data at environmental exposure levels, or direct human epidemiological links to microcephaly.^[89] Brazil's Ministry of Health and the World Health Organization promptly rejected the allegation, emphasizing that pyriproxyfen concentrations used (typically 1-10 ppb) were far below mammalian toxic thresholds and aligned with WHO guidelines for drinking water treatment, where no adverse human health effects had been documented in prior global applications.^[90] An ecological analysis of 141 municipalities in Pernambuco state, a microcephaly hotspot, found no statistical correlation between pyriproxyfen application in stored water and microcephaly prevalence (prevalence ratio not significantly elevated; p>0.05), with cases occurring in non-treated areas and absent in some treated ones.^[91] Causal evidence instead supported Zika virus infection during pregnancy: reverse-transcription PCR confirmed Zika RNA in amniotic fluid and brain tissue of microcephalic fetuses from affected pregnancies, with spatiotemporal clustering matching Zika's 2015 emergence in Brazil (over 4,000 suspected microcephaly cases reported by December 2015, predominantly in Zika-endemic northeast regions).^[92] Pyriproxyfen's low acute and reproductive toxicity in mammals (LD50 >5,000 mg/kg in rats; no teratogenicity at doses up to 300 mg/kg/day) further precluded causation at trace aquatic levels, as affirmed by toxicologists and entomologists.^[93]^[89] A 2017 Brazilian cohort study reinforced this, detecting no pyriproxyfen-microcephaly association after adjusting for Zika exposure.^[92]

Other Environmental and Health Concerns

Studies on non-target aquatic organisms have identified sublethal effects of pyriproxyfen, particularly in Daphnia magna, where exposure to environmentally relevant concentrations led to reproductive impairments and reduced survival rates over 21 days.^[94] ^[82] Similarly, chronic toxicity assessments indicate high sensitivity in aquatic invertebrates, with ecological risk assessments (ERA) highlighting potential population-level impacts from prolonged low-level exposure.^[80] However, field-based ERA models for approved agricultural and vector control applications generally predict low risks to broader aquatic ecosystems, attributing this to pyriproxyfen's rapid degradation in water (half-life of 2-7 days under aerobic conditions) and minimal bioaccumulation potential.^[85] ^[95] In mammalian toxicology, high-dose rodent studies conducted in 2024 reported developmental alterations, including ultrastructural changes in neural cells, reduced brain width, and decreased neuron counts in the motor cortex following prenatal exposure.^[96] ^[97] These effects, observed at doses orders of magnitude above typical human environmental exposures (e.g., >100 mg/kg/day versus <0.01 mg/kg/day from residues), have not been linked to adverse outcomes in human epidemiology or low-dose scenarios, underscoring their limited relevance to real-world risk profiles.^[98] A 2024 review of pyriproxyfen's dual role as an insect growth regulator emphasizes its efficacy in mosquito vector control—such as disrupting Aedes aegypti populations to curb Zika virus transmission—while noting that regulated use at concentrations like 0.01 mg/L poses negligible health risks per World Health Organization evaluations, with disease prevention benefits substantially outweighing documented hypothetical concerns in controlled applications.^[99]

Regulatory Status

Approvals by Key Agencies

The United States Environmental Protection Agency (EPA) first registered pyriproxyfen in 1995 for pesticide uses, including public health applications against pests such as fleas, ants, and cockroaches.^[100] The agency has established tolerances for residues in food commodities through multiple rulemakings, with the most recent in 2021 confirming safety based on available data.^[87] Pyriproxyfen underwent registration review, culminating in an interim decision in 2019 that affirmed its low-risk classification for human health while requiring label amendments for environmental protections.^[31] The World Health Organization (WHO) endorses pyriproxyfen for integrated vector management, particularly as a larvicide for mosquito control in drinking water sources and containers.^[4] WHO specifications evaluate it for public health pesticides, recommending dosages not exceeding 0.01 mg/L in potable water to minimize risks while effectively disrupting insect development.^[101] Products containing pyriproxyfen have received WHO prequalification for vector control, supporting its role in disease prevention without evidence of significant human health hazards at approved levels.^[102] In the European Union, pyriproxyfen's approval as an active substance was renewed in 2020 under Regulation (EC) No 1107/2009, enabling its use as an insecticide on crops like citrus and pome fruits. The European Food Safety Authority (EFSA) conducted peer reviews, including in 2019, concluding acceptable risks for representative uses after assessing mammalian toxicology and residue data, though with mitigation for potential aquatic organism exposure.^[103] Maximum residue levels have been reviewed and adjusted as recently as 2022, reflecting ongoing regulatory confidence absent prohibitions driven by unsubstantiated critiques.^[104]

Usage Guidelines and Restrictions

Pyriproxyfen is applied in mosquito vector control at low concentrations, typically 0.01 mg/L (10 ppb) in potable water storage or breeding sites, as recommended by the World Health Organization Pesticide Evaluation Scheme (WHOPES) to inhibit larval development without exceeding safe thresholds for human use.^[105] Higher rates up to 0.05-0.1 mg/L may be used in specific non-potable aquatic habitats like catch basins, providing residual activity for 48-50 weeks depending on formulation and environmental factors.^[106] Application methods emphasize targeted delivery, such as granules or emulsifiable concentrates in larval habitats, to maximize efficacy while minimizing dispersion.^[45] Handlers and applicators must follow product label requirements for personal protective equipment (PPE), including long-sleeved shirts, long pants, chemical-resistant gloves, shoes plus socks, and protective eyewear; respirators are required during mixing/loading if ventilation is inadequate.^[107] Post-application re-entry intervals vary by product but generally restrict access until sprays dry or dusts settle, with emphasis on washing exposed skin and changing contaminated clothing to prevent dermal exposure.^[108] Restrictions prohibit direct application to open water bodies beyond approved vector breeding sites to avoid non-target impacts on aquatic organisms, given pyriproxyfen's toxicity to fish and crustaceans at concentrations above 0.001 mg/L.^[109] Buffer zones and runoff prevention measures, such as vegetated strips, are mandated near sensitive ecosystems like wetlands, with ongoing monitoring recommended for residue levels and biodiversity effects.^[1] Since 2020, guidelines have prioritized autdissemination techniques—where gravid females transfer pyriproxyfen to breeding sites—to reduce broad environmental release and enhance precision in urban settings.^[46]

References

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Pyriproxyfen General Fact Sheet
Pyriproxyfen is an insect growth regulator that mimics a natural hormone, disrupting the growth of young insects and eggs, and preventing them from maturing.
[2]
Pyriproxyfen | C20H19NO3 | CID 91753 - PubChem - NIH
Pyriproxyfen is a pyridine-based pesticide which is found to be effective against a variety of arthropoda. It was introduced to the US in 1996, to protect ...
[3]
An investigation on some toxic effects of pyriproxyfen in adult male ...
Pyriproxyfen caused reduced body and testis weights, and testicular abnormalities like shrinkage of seminiferous tubules and reduced lumen diameter in mice.
[4]
[PDF] Use for Vector Control in Drinking-water Sources and Containers
Pyriproxyfen is a broad-spectrum insect growth regulator with insecticidal activity against public health insect pests: houseflies, mosquitoes and cockroaches.<|separator|>
[5]
[PDF] Sumilarv® 0.5G - Sumitomo Chemical (UK)
SumiLarv is a novel mosquito larval control agent based on the insect growth regulator pyriproxyfen. It was invented and developed by Sumitomo Chemical Co. Ltd.
[6]
ICSC 1269 - PYRIPROXYFEN - INCHEM
Melting point: 48-50°C Boiling point: 318°C Flash point: 119°C c.c.. Density (at 20°C): 1.14 g/cm³. Solubility in water, mg/l at 20°C: 0.101 (practically ...Missing: stability degradation
[7]
[PDF] pyriproxyfen Chemical name IUPAC: CA: 4-phen
Solubility: water 0.367 ± 0.004 mg/l at 25 ± 1°C. Hydrolysis: pyriproxyfen was stable in aqueous buffers in the dark at pH 4.0, 7.0 and 9.0 at 50°C and at pH 5 ...
[8]
Fate of Pyriproxyfen in Soils and Plants - PMC - PubMed Central
Mar 13, 2020 · In soils, the photodegradation of pyriproxyfen proceeds slowly with half-lives ranging from 10 to 20 weeks depending on the soil type and abiotic factors.Missing: stability photostability
[9]
Pyriproxyfen - an overview | ScienceDirect Topics
Mechanism of action Although a carbamate, pyriproxyfen has no cholinesterase activity but is a potent insect juvenile hormone mimetic.
[10]
Molecular action of pyriproxyfen: Role of the Methoprene-tolerant ...
PPF is believed to affect mosquito reproduction by disturbing the normal action of endogenous hormones. Many studies of other insects have demonstrated that the ...
[11]
The inhibition of ecdysone signal pathway was the key of ... - PubMed
The inhibition of ecdysone signal pathway was the key of pyriproxyfen poisoning for silkworm, Bombyx mori ... However, the poisoning mechanism is still unclear.
[12]
The inhibition of ecdysone signal pathway was the key of ...
Pyriproxyfen poisoning in silkworms is caused by the inhibition of the ecdysone signal pathway, which decreases ecdysone levels and affects downstream ...
[13]
Pyriproxyfen - an overview | ScienceDirect Topics
Pyriproxyfen acts as a juvenile hormone (JH) mimic, artificially maintaining the regulation of molting after natural JH levels have dropped; this arrests the ...
[14]
Pyriproxyfen, a juvenile hormone analog, damages midgut cells and ...
Sep 4, 2019 · Pyriproxyfen, a juvenile hormone analog, has a unique mode of action that affects embryogenesis (Maharajan et al., 2018), metamorphosis ...
[15]
Effects of pyriproxyfen, a juvenile hormone analog, on development ...
Oct 13, 2017 · Using in vitro pupal integument explant cultures, pyriproxyfen (at 1 and 10 μM in the medium) caused a significant inhibition of ecdysteroid ...
[16]
Lethal and Sublethal Effects of Pyriproxyfen on Apis and Non ... - NIH
Nov 17, 2020 · Pyriproxyfen is an insect growth regulator that mimics the juvenile hormone activity. ... By disrupting the hormonal system of the insects, ...
[17]
Stage-specific action of juvenile hormone analogs - PMC - NIH
In the swallowtail butterfly, Papilio demoleus, JHAs pyriproxyfen and diofenolan, induced similar effects as in other lepidopteran insects in prolonging larval ...
[18]
Identification of plant compounds that disrupt the insect juvenile ...
Three major classes of IGRs are commercially available (3). These IGRs include juvenile hormone (JH) agonists (methoprene and pyriproxyfen), ecdysone agonists ( ...
[19]
Effect of the juvenile hormone agonist pyriproxyfen on larval and ...
Ecdysial failure was observed as a prominent result of pyriproxyfen application, indicating that the JHA disrupts the secretion or activity of ecdysone ( ...
[20]
Evaluation of pyriproxyfen, a juvenile hormone analog, on ...
Pyriproxyfen treatment increased the duration of pupal development. In addition, enzyme immunoassay measurements of ecdysteroids in whole body extracts of pupae ...
[21]
Ovicidal activity of three insect growth regulators against Aedes and ...
Insect growth regulators, pyriproxyfen, azadirachtin and diflubenzuron, are causing abnormal embryonic development in eggs of Aedes albopictus mosquito.
[22]
Effects of pyriproxyfen, a juvenile hormone analog, on development ...
Results. Treatment with pyriproxyfen caused a blockage of the pupal–adult development, as the intoxicated pupae died being trapped in the old exuvium.
[23]
Pyriproxyfen, a novel insect growth regulator for controlling ...
Pyriproxyfen, a novel juvenile hormone mimic, is a potent suppressor of embryogenesis and adult formation of the sweetpotato whitefly, Bemisia tabaci ...
[24]
Insect Growth and Development Regulator Toxicosis in Animals
Pyriproxyfen (4-Phenoxyphenyl (R/S)-2-(2-pyridyloxy)propyl ether 2-[1-(4-phenoxyphenoxy)propan-2-yloxy]pyridine), has a chemical formula of C 20H 19NO 3, with a ...Missing: IUPAC name<|separator|>
[25]
The Behavioral Toxicity of Insect Growth Disruptors on Apis mellifera ...
Exposure to the juvenile hormone analog pyriproxyfen consistently shortened the duration of pupation, and pyriproxyfen and diflubenzuron inconsistently reduced ...
[26]
The synthesis and application of insect growth regulator pyriproxyfen
Pyriproxyfen, a new insecticide, also an insect growth regulator belonging to juvenile hormone analogues, was discovered and developed by Sumitomo Chemical ...
[27]
Pyriproxyfen - an overview | ScienceDirect Topics
In 1991 a new juvenoid pyriproxyfen 112 was developed by Sumitomo, it is used to control mainly whiteflies on vegetables and cotton.
[28]
Pyriproxyfen - an overview | ScienceDirect Topics
Pyriproxyfen is a potent insecticide that acts as a mimetic of insect juvenile hormone. It is effective in killing flea eggs and larvae.Missing: history | Show results with:history
[29]
Horizontal transfer of the insect growth regulator pyriproxyfen to ...
Jun 19, 2003 · Loh, Y.P. & Yap, H.H. (1989) Laboratory studies of the efficacy and sublethal effects of an insect growth regulator, pyriproxyfen (S-31183) ...
[30]
Lethal and sublethal effects of two insect growth regulators on adult ...
Pyriproxyfen is a juvenile hormone analog with relatively low mammalian toxicity that was first registered in Japan in 1991 for controlling public health ...
[31]
[PDF] Pyriproxyfen Interim Registration Review Decision Case Number ...
Sep 23, 2019 · During the 60-day public comment period for the pyriproxyfen PID, which opened on August 8,. 2018 and closed on October 9, 2018, the agency ...
[32]
Pyriproxyfen - FleaScience
Sumitomo trademarked pyriproxyfen as Sumilarv in Japan. In 1990, it entered the United States and was given the trademarked name Nylar by McLaughlin Gormley ...
[33]
Pyriproxyfen (Ref: S 9318) - AERU - University of Hertfordshire
Sep 4, 2025 · By binding to the Met receptor, it disrupts normal hormonal signalling, leading to impaired metamorphosis, sterilization, and inhibition of egg ...Top · Environmental Fate · EcotoxicologyMissing: mechanism | Show results with:mechanism
[34]
Impact of Long-Term Pyriproxyfen Exposure on the Genetic ... - MDPI
Despite the effectiveness of this larvicide and its recommended use in Brazil by the National Dengue Control Program (PNCD), there are few studies on the ...
[35]
Community effectiveness of pyriproxyfen as a dengue vector control ...
Due to its very low mammalian toxicity [9], pyriproxyfen is approved by the World Health Organization (WHO) for the treatment of potable water against ...Missing: endorsement | Show results with:endorsement<|separator|>
[36]
Evaluation of Aedes aegypti control intervention with pyriproxyfen by ...
Oct 3, 2024 · This study was conducted in Manacapuru city, Amazonas, Brazil, where 1,000 pyriproxyfen dissemination stations were deployed and monitored from ...
[37]
Development and Characterization of Pyriproxyfen-Loaded ...
In this study, we propose a novel oil/water nanoemulsion loaded with pyriproxyfen obtained using a low-energy method (phase inversion composition method). This ...
[38]
Development and Characterization of Pyriproxyfen-Loaded ...
Development and Characterization of Pyriproxyfen-Loaded Nanoemulsion for Housefly Control: Improving Activity, Reducing Toxicity, and Protecting Ecological ...
[39]
[PDF] Pyriproxyfen - Regulations.gov
There are data available on pyriproxyfen usage for twenty-one crops out of about 60 total crops surveyed by a private agricultural pesticide market research ...
[40]
Effect of Pyriproxifen 10% EW against sucking insect pest population ...
Jan 20, 2021 · The study indicated that spraying of pyriproxifen 10% EW @ 200 gai/ha has recorded significantly higher seed cotton yield (19.43 q/ha) with maximum per cent ...
[41]
Cottony Cushion Scale / Citrus / Agriculture - UC IPM
Insect growth regulators prevent vedalia beetle from completing pupation and emerging as adults; pyriproxyfen also prevents the beetle eggs from hatching.Missing: efficacy | Show results with:efficacy
[42]
[PDF] US EPA, Pesticide Product Label, PYRIPROXYFEN 10% EC,06/24 ...
Jun 24, 2021 · Product Name: Pyriproxyfen 10% EC. EPA Registration Number: 53883-280. Application Date: 02/21/2020. Decision Number: 560323. Dear Ms. Adamson ...
[43]
Effects of operational and environmental factors on evolution of ...
Pyriproxyfen has been an important insecticide used as part of an integrated pest management (IPM) program for the sweetpotato whitefly, Bemisia tabaci ...
[44]
(PDF) Field Efficacy of Insect Growth Regulator, Pyriproxyfen against ...
Sep 4, 2025 · However, all the three pyriproxyfen dosages were significantly more effective against nymphal population of white fly at 1, 3 and 7 DAS as ...Missing: citrus | Show results with:citrus
[45]
Use of pyriproxyfen in control of Aedes mosquitoes - PubMed Central
Jun 12, 2020 · Pyriproxyfen (PPF) is an insecticide that prevents juvenile Aedes mosquitoes from becoming adults.
[46]
Mosquitoes as pesticide disseminators: Advancing pyriproxyfen ...
Pyriproxyfen (PPF), an insect growth regulator (IGR), offers a promising alternative due to its unique mode of action, mimicking juvenile hormone to disrupt ...
[47]
Inhibition of adult emergence of Aedes aegypti in simulated ...
The efficacy of a novel controlled-release formulation of the insect growth regulator pyriproxyfen, designed to inhibit adult emergence for 6 months (the ...
[48]
[PDF] PYRIPROXYFEN AS A MOSQUITO LARVICIDE
Efficacy was good for up to 6 months with the higher dose rates inhibiting emergence of adult mosquitoes by >87% (Fig. 7). At a dosage of 27 ppb pyriproxyfen ...
[49]
Community effectiveness of pyriproxyfen as a dengue vector control ...
Jul 17, 2017 · There is evidence that pyriproxyfen may effectively reduce the density of immature mosquito stages when applied to identified breeding sites.
[50]
Potential Use of Pyriproxyfen for Control of Aedes aegypti (Diptera
Pyriproxyfen is classified as a juvenile hormone (JH) analog and has been used against a range of arthropods since its introduction to the agrochemical market ...
[51]
A Possible Link Between Pyriproxyfen and Microcephaly - PMC
Use of Pyriproxyfen in water supply in Brazil. Pyriproxyfen has been used as an insecticide in northeast Brazil in response to an outbreak of dengue starting ...
[52]
a pragmatic, before–after control–intervention paired-series trial
Sep 19, 2024 · Mosquito-disseminated pyriproxyfen for mosquito-borne disease control in Belo Horizonte, Brazil: a pragmatic, before–after control–intervention ...
[53]
Brazilian Populations of Aedes aegypti Resistant to Pyriproxyfen ...
Oct 6, 2022 · Pyriproxyfen has been used to control Ae. aegypti in public health throughout Brazil since 2014, largely attributable to insecticide resistance ...
[54]
A novel approach to flea control on cats, using pyriproxyfen - PubMed
Pyriproxyfen is a new insect growth regulator with potent activity against developing stages of the cat flea, Ctenocephalides felis.
[55]
Dinotefuran + Pyriproxyfen - VCA Animal Hospitals
Dinotefuran/pyriproxyfen (brand name Vectra®) is a topical (spot-on) antiparasitic drug used to repel and kill fleas in dogs and puppies that are at least 8 ...
[56]
Smarter Flea Control - Entomology - University of Kentucky
The methoprene and pyriproxyfen-impregnated collars are virtually 100% effective at preventing new flea eggs from hatching for at least 6 months (essentially ...
[57]
Pyriproxyfen; Pesticide Tolerances - Federal Register
Feb 22, 2016 · Pyriproxyfen is currently registered for flea and tick control (home environment and pet treatments) as well as products for ant and roach ...
[58]
Use of pyriproxyfen in control of Aedes mosquitoes
Jun 12, 2020 · Pyriproxyfen (PPF) is an increasingly used hormone analogue that prevents juvenile Aedes mosquitoes from becoming adults and being incapable of transmitting ...
[59]
Mosquito-Disseminated Pyriproxyfen Yields High Breeding-Site ...
Apr 7, 2015 · We show that mosquito-disseminated PPF yielded high coverage of dwellings (up to 100%) and SBSs (up to 94.3%). Juvenile mosquito mortality in SBSs (about 4% at ...
[60]
Effect of pyriproxyfen on developing stages and embryogenesis of ...
Mortality rates were 86 and 100% at concentrations of 0.2 and 0.4 mg AI L(-1) respectively. Pyriproxyfen suppressed embryogenesis when CRS females were treated ...
[61]
Effect of pyriproxyfen on developing stages and embryogenesis of ...
Aug 10, 2025 · Mortality rates were 86 and 100% at concentrations of 0.2 and 0.4 mg AI L(-1) respectively. Pyriproxyfen suppressed embryogenesis when CRS ...
[62]
California Red Scale and Yellow Scale / Citrus / Agriculture - UC IPM
In the 2020s, numerous California red scale populations in the San Joaquin Valley developed resistance to the insect growth regulator pyriproxyfen.
[63]
Efficacy of permethrin, dinotefuran and pyriproxyfen on adult fleas ...
The egg laying inhibition was over 92.3% for up to 29 days (p<0.05). The adult emergence inhibition remained 100% during 8 weeks after treatment and was 99.8% ...
[64]
A novel approach to flea control on cats, using pyriproxyfen
Aug 6, 2025 · For subsequent infestations no eggs were produced from treated cats from day 8 through day 30. Egg production was still reduced by ≥95.8% ...
[65]
Impact of treated dogs on flea life stages in a simulated home ...
Sep 7, 2012 · This study evaluated the efficacy of imidacloprid + pyriproxyfen (PPF) (Advantage® II for Dogs) and spinosad (Comfortis®) against established C. felis ...
[66]
Pyriproxyfen - National Pesticide Information Center
Dec 2, 2015 · Pyriproxyfen is an insect growth regulator that mimics hormones, disrupting growth, and is used on pets for fleas and ticks. It is low in ...
[67]
Novel insecticides and generalist predators support conservation ...
Our study demonstrates that the insecticides tested are selective and compatible with sustainable pest management in the Arizona cotton system.
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Intake of Pyriproxyfen Through Contaminated Food by the Predator ...
Understanding the sublethal effects of insecticides on non-target insects is crucial for effective IPM. This study aimed to evaluate the impact of pyriproxyfen ...
[69]
Field evaluation of pyriproxyfen and spinosad mixture for the control ...
In this study we evaluated the operational efficiency of a mixture composed of pyriproxyfen (an insect growth regulator) and spinosad (a biopesticide) against a ...
[70]
[PDF] Comparative Efficacy of Temephos and Pyriproxyfen on Aedes ...
Nov 13, 2024 · The granular formulation of 0.5% pyriproxyfen at. 0.05-0.1 mg/L inhibited the emergence of Aedes togoi in brackish water in rock pools from 5 to ...
[71]
Ultimate fate and toxicological consequences of insecticide ...
Degradation of pyriproxyfen revealed 6 metabolites most of which persisted for more than 30 days in soil. Metabolites C, E and F caused toxicity to soil ...Missing: photostability | Show results with:photostability
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Association of low concentrations of pyriproxyfen and spinosad as ...
It altered the behavior and development of larvae, effectively inhibiting the emergence of adult insects for a long period. The results confirm the hypothesis ...
[73]
(PDF) Pyriproxyfen: villain or good guy? A brief review - ResearchGate
Oct 31, 2024 · (WHO) considers the use of PPF at a concentration of 0.01 mg/L as unlikely to pose health risks,. recent studies have unveiled potential risks ...
[74]
[PDF] Federal Register/Vol. 64, No. 71/Wednesday, April 14, 1999/Rules ...
Apr 14, 1999 · Acute toxicity studies with technical pyriproxyfen: Oral LD50 in the rat is >5,000 milligram/ kilogram (mg/kg) for males and females - Toxicity ...
[75]
[PDF] Pyriproxyfen. Human Health Draft Risk Assessment for Registration ...
Jun 14, 2025 · ... EPA Registration Number 59639-114 (EPA acceptance date. 12/13/2012). Granular (G) formulation of pyriproxyfen. Broadcast ground and aerial ...
[76]
Pyriproxyfen; Pesticide Tolerances - Federal Register
Dec 12, 2012 · With respect to carcinogenicity pyriproxyfen has been classified as a “Group E” chemical—no evidence for carcinogenicity to humans based on the ...
[77]
Peer review of the pesticide risk assessment of the active substance ...
Based on available genotoxicity studies (in vitro and in vivo), it was concluded that pyriproxyfen is not genotoxic. In the long‐term toxicity study with rats, ...
[78]
[PDF] PYRIPROXYFEN - Extranet Systems
Although there was clear evidence of liver toxicity during the first year of exposure, the liver effects were less prominent by the end of the treatment period.
[79]
Environmental risk assessment (ERA) of pyriproxyfen in non-target ...
Pyriproxyfen caused a high risk at concentrations detected in aquatic environments for Daphnia magna, with probable reproductive effects and occasional survival ...Missing: impacts | Show results with:impacts
[80]
[PDF] Preliminary Ecological Risk Assessment for the Registration Review ...
Aug 14, 2017 · Aerobic Soil Metabolism Half Life. (25oC). 27 days (3X aerobic soil ... (1995) Artificial Sunlight Photodegradation of Pyriproxyfen in ...
[81]
[PDF] Pyriproxyfen: Registration Review Drinking Water Assessment
Jun 22, 2017 · The maximum pyriproxyfen concentration observed in non-targeted surface water monitoring data is 1.34 µg/L. The maximum concentration of ...
[82]
Environmental risk assessment (ERA) of pyriproxyfen in non-target ...
Pyriproxyfen (PPF) is a synthetic substance and an insect juvenile hormone agonist with growth regulating effect. It is used worldwide as a pesticide in ...
[83]
Modification of the existing maximum residue levels for pyriproxyfen ...
Sep 23, 2022 · Considering the low contribution of residues in RAC apricots (0.03% acceptable daily intake (ADI)) and peaches (0.12% ADI) to the overall ...
[84]
2021 Human Health Benchmarks for Pesticides | US EPA
Jan 15, 2025 · The HHBPs Table includes noncancer benchmarks for exposure to pesticides that may be found in surface or ground water sources of drinking water.
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Peer review of the pesticide risk assessment of the active substance ...
Jul 17, 2019 · Pyriproxyfen residues can be monitored in food and feed of plant origin by the QuEChERS method using high-performance liquid chromatography with ...
[86]
Large-Scale Operational Pyriproxyfen Autodissemination ...
Feb 1, 2020 · Instead, we treated the buffer zone with a barrier pesticide to reduce adult influx. While the barrier applications worked to some degree (about ...
[87]
Pyriproxyfen; Pesticide Tolerances - Federal Register
Nov 15, 2021 · EPA has previously published several tolerance rulemakings for pyriproxyfen, in which EPA concluded, based on the available information ...
[88]
[PDF] A Possible Link Between Pyriproxyfen and Microcephaly | SECTI
garding Dengue-Zika, microcephaly, and mass-spraying with chemical poisons, Red Universitaria de Ambiente y. Salud (February 3, 2016), http://www.reduas.com.ar/.<|separator|>
[89]
Did A Pesticide Cause Microcephaly In Brazil? Unlikely, Say Experts
Feb 18, 2016 · A report last week has raised questions about a pesticide used to kill mosquito larvae, linking its use to the increase in cases of microcephaly in Brazil.Missing: rumor | Show results with:rumor
[90]
Brazil, WHO officials deny pesticide-microcephaly link - CNN
Feb 18, 2016 · Brazilian health officials and the World Health Organization deny links between a well-known pesticide, Pyriproxyfen, and microcephaly.
[91]
Pyriproxyfen and the microcephaly epidemic in Brazil - NIH
Our results show that the prevalence of microcephaly was not higher in the areas in which pyriproxyfen was used.
[92]
Zika virus, not vaccines or insecticide, linked to birth defects in Brazil
Dec 13, 2017 · The work, by Brazilian scientists, suggested there is no link between the cases of microcephaly and exposure to the insecticide pyriproxyfen, nor to maternal ...Missing: origin | Show results with:origin
[93]
Scientists debunk theory linking pesticide, not Zika, to birth defects
Feb 16, 2016 · Brazil's Ministry of Health rejected any link between the chemical and the microcephaly outbreak, noting the World Health Organization deems ...
[94]
Pyriproxyfen Contamination in Daphnia magna: Identifying Early ...
Feb 2, 2024 · Taking into account pyriproxyfen residues resulting from agricultural applications in water during the initial weeks post-application, these ...<|control11|><|separator|>
[95]
Environmental fate and properties of pyriproxyfen - J-Stage
This paper gathers, combines, and abridges important environmental fate and property data on pyriproxyfen for academics, environmental scientists and ...
[96]
Developmental toxicity of pyriproxyfen induces changes in the ...
Mar 26, 2024 · This study aims to investigate the effects of PPF on the structure and ultrastructure of brain cells and its influence on the skull ossification process during ...Missing: rodent | Show results with:rodent
[97]
Evaluation of developmental milestones and of brain measurements ...
Sep 8, 2024 · The present study evaluated whether prenatal exposure to pyriproxyfen affects neonatal development and brain structure in rats.Missing: changes | Show results with:changes
[98]
Pyriproxyfen, villain or good guy? A brief review - SciELO
Reduced brain mass, changes in forebrain and midbrain morphologies, reduced cell proliferation and increased cell death in the brain, neurodevelopmental ...
[99]
Pyriproxyfen, villain or good guy? A brief review - SciELO
On water surface, PPF is susceptible to photodegradation and biological catalysis, reaching a half-life of 21 days, but in anaerobic conditions or sediments, ...
[100]
[PDF] PYRIPROXYFEN - National Pesticide Information Center
Pyriproxyfen is considered low in toxicity for humans and other mammals. If ... Based on these studies, the EPA has classified pyriproxyfen as not likely to cause ...
[101]
[PDF] WHO SPECIFICATIONS AND EVALUATIONS FOR PUBLIC ...
The exisiting specification for pyriproxyfen MR was published in December 2021 based on revisions to the original data package provided by Sumitomo Chemical Co.
[102]
Pyriproxyfen - World Health Organization (WHO)
Pyriproxyfen | WHO - Prequalification of Medical Products (IVDs, Medicines, Vaccines and Immunization Devices, Vector Control)Missing: IVM | Show results with:IVM
[103]
Peer review of the pesticide risk assessment of the active substance ...
Jul 17, 2019 · The conclusions were reached on the basis of the evaluation of the representative uses of pyriproxyfen as an insecticide on citrus fruit, pome fruit (apple, ...
[104]
Review of the existing maximum residue levels for pyriproxyfen ...
Nov 30, 2022 · EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide active substance pyriproxyfen.
[105]
[PDF] pyriproxyfen-chemical-fact-sheet.pdf
The recommended dosage of pyriproxyfen in potable water in containers should not exceed 0.01 mg/l under WHOPES. JMPR evaluated pyriproxyfen and concluded that ...
[106]
Residual Activity of Pyriproxyfen Against Mosquitoes in Catch ...
Sep 1, 2020 · In conclusion, pyriproxyfen can be used to effectively control mosquitoes in catch basins for 48-50 wk, depending on the rate of application.
[107]
[PDF] Pyriproxyfen Group 7C INSECTICIDE - Atticus LLC
Do not plant any crop other than those with registered pyriproxyfen uses in treated areas sooner than 30 days after the last application. MANAGING INSECT ...
[108]
[PDF] Pitch® 0.86 EC - Greenbook.net
PERSONAL PROTECTIVE EQUIPMENT (PPE):. Applicators and other handlers must wear: • Coveralls over short-sleeved shirt and short pants or long-sleeved shirt and ...
[109]
https://www.sigmaaldrich.com/DE/de/sds/sial/34174