Chemicals - Pyriproxyfen

PYRIPROXYFEN

From: An investigation on some toxic effects of pyriproxyfen in adult mail mice; (Shahid; Zaidi; Akbar and Saeed); Iranian Journal Basic Med Sci, 2019 Sep; 22 (9): 997 – 1003

• Widely used to combat arthropods, including insects, weeds, and annual grasses.

• It has high stability in the environment, and persistence via the food chain causes detrimental effects on non-target species.

• Pyriproxyfen caused a reduction in body weight gain as well as damage to testicular architecture in mice and thus may potentially interfere with spermatogenesis. Findings in an outbred strain of mice can be extrapolated fairly reliably to the human model.
  

From: Use of High-Performance Liquid Chromatography-mass Spectrometry of Adipose Tissue for Detection of Bioaccumulation of Pyriproxyfen in Adults of Lithobates catesbeianus; Nimet et al; Bulletin of Environmental Contamination and Toxicology (2021) 107:911-916

• Adult frogs exposed to the standard dose recommended by the World Health Organisation (WHO) showed bioaccumulation of pyriproxyfen in adipose tissue significantly higher than control animals. Baiting six times with pyriproxyfen will thus result in significant bioaccumulation.

• Other studies in fish have had similar findings.
  

From: Fate of pyriproxyfen in Soils and Plants; Devilliers; Toxics 2020, 8, 20; doi:103390/toxics8010020; www.mdpi.com/journal/toxics

• This study concludes that it is compulsory to study the behaviour of pyriproxyfen for a given crop in the growing conditions of a specific area to estimate whether the established pre-harvest time ensures that the residue levels are below the maximum residue level (MRL) that is the highest concentration of pesticide that is legally tolerated in or on food when it is applied under good agricultural practices. Thus, recently, EFSA proposed 0.4 mg/kg as MRL for the tomato and 0.7 mg/kg for the citrus. The fire ant program is spraying pyriproxyfen at 5g/kg. On the permit, it states: Produce that is traded for human consumption, which has direct contact with the bait, must be washed after harvest and prior to marketing. This might not be so helpful, as according to the paper by Devillers (2020), the half-life of pyriproxyfen in plants ranges from less than one week to about three weeks, depending on the crop and the experimental conditions.
  

From: Effects of Pyriproxyfen on Viability and Increase of Intracellular Lipids in HepG2 Cell Line; Lamberti et al, Occup Med Health Aff 2014, 2:5

• This study suggests that pyriproxyfen is strongly cytotoxic to human hepatocytes (liver cells). This concurs with the toxicity label for the chemical, which lists the general human health issues as possible liver toxicant, possible blood toxicant and endocrine issues – estrogenic effect.
  

From: Ultimate fate and toxicological consequences of insecticide pyriproxyfen and its metabolites in soil ecosystem; Kumari et al; 2021; https://doi.org/10.10166/j.envadv.2021.100040

• Pyriproxyfen can degrade into approximately 10 metabolites. Of the six studied, their residues persisted for more than 30 days in soil with half lives varying from 2.6 to 30 days. Metabolites C, E and F caused toxicity to soil enzymes. Considering the persistence behaviour and toxicological consequences of metabolites, further investigations are needed to prevent their harmful effect on non-target organisms and the associated environment.
  

From: The impact of pyriproxyfen on the development of honey bee (Apis mellifera L.) colony in field; Chen et al, 2016, Journal of Asia-Pacific Entomology

• A study by Chen et al (2016) indicates that pyriproxyfen has negative impacts on both larval and adult honey bees and royal jelly production, especially under high pyriproxyfen concentrations.
  

From: Indirect transfer of pyriproxyfen to European honeybees via an autodissemination approach; Kanchariapalli et al; PLoS Negl Trop Dis 15 (1D): e0009824. https://doi.org/10.1371/journal.pntd.0009824

• The argument by the program is that honey bees will not go for the baits. However, they do not have to eat the bait directly. A study of autodissemination of pyriproxyfen found that pyriproxyfen-treated mosquitoes can contaminate nectar sources, which results in the indirect transfer of pyriproxyfen to European honey bees.

From: The effects of the insecticide Pyriproxyfen on germination, development and growth responses of maize seedlings; Coskun et al

• A study looked at the effect of pyriproxyfen and suggests that excessive and uncontrolled usage of the pesticide pyriproxyfen results in phytotoxic effects by inducing some morphological, anatomical, physiological and metabolic processes. In addition, as chemical compounds accumulate, pyriproxyfen is thought to adversely affect all living beings feeding on plants that are exposed to chemicals, and also negatively affects the environmental factors such as soil, air and water.

From: Environmental fate and properties of pyriproxyfen; Sullivan et al; California Environmental Protection Agency, J. Pestic. Sci., 33 (4), 339-350 (2008) DOI: 10.1584/jpestics.R08-02

• Pyriproxyfen is toxic to insects during their embryonic, last larval, or reproductive stages and is particularly effective against pests that are relatively insensitive to conventional insecticides, such as whiteflies, mealworms, scales and thrips.

• If released in water, pyriproxyfen adsorbs onto suspended solids and organic matter and retains biological activity for up to two months.

• The low solubility, high patrician coefficients, and hydrophobicity of pyriproxyfen are consistent with chemicals that are known to be environmentally persistent.

• In anaerobic conditions, such as brackish waters or sediments, pyriproxyfen is much more stable, immutable, and toxic to aquatic invertebrates.
  

Given its potential to persist, prudence should be used when applying pyriproxyfen to or near water bodies, and precautions must be taken to avoid or mitigate drift or runoff to surface waters.

Pyriproxyfen Research Articles

• An investigation into some toxic effects of pyriproxyfen in adult male mice

• Distance® ANT BAIT safety instructions

• Pyriproxyfen — toxicity, side effects, diseases, and environmental impacts
  Tuesday, November 21, 2017 by Frances Bloomfield

• An investigation into some toxic effects of pyriproxyfen in adult male mice
  Read more

• Use of High-Performance Liquid Chromatography-Mass Spectrometry of Adipose Tissue for Detection of Bioaccumulation of Pyriproxyfen in Adults of Lithobates catesbeianus
  Read more

• Fate of Pyriproxyfen in Soils and Plants
  Read more

• Effects of Pyriproxyfen on Viability and Increase of Intracellular Lipids in HepG2 Cell Line
  Read more

• Ultimate fate and toxicological consequences of insecticide pyriproxyfen and its metabolites in the soil ecosystem
  Read more

• The impact of pyriproxyfen on the development of honey bee (Apis mellifera L.) colony in the field
  Read more

• Indirect transfer of pyriproxyfen to European honeybees via an autodissemination approach
  Read more

• The Effects of the insecticide pyriproxyfen on germination, development, and growth responses of maize seedlings
  Read more

• Product Label, Pyriproxyfen 0.86 EC VPP Insect Growth Regulator – Phytotoxicity noted
  Read more

• Comparative attractiveness of two pyriproxyfen-based ant baits (Distance® and Distance® Plus) to invasive and nuisance ants in Australia
  Read more

• S-Methoprene Information

Explore More

From: An investigation on some toxic effects of pyriproxyfen in adult male mice; (Shahid; Zaidi; Akbar and Saeed); Iranian Journal Basic Med Sci, 2019 Sep; 22 (9): 997 - 1003

• Widely used to combat arthropods, including insects, weeds, and annual grasses.

• It has high stability in the environment, and persistence via food chain causes detrimental effects on non-target species.

• Pyriproxyfen caused reduction in body weight gain as well as damage to testicular architecture in mice and thus may potentially interfere with spermatogenesis. Findings in an outbred strain of mice can be extrapolated fairly reliably to the human model.

From: Use of High-Performance Liquid Chromatography-mass Spectrometry of Adipose Tissue for Detection of Bioaccumulation of Pyriproxyfen in Adults of Lithobates catesbeianus; Nimet et al; Bulletin of Environmental Contamination and Toxicology (2021) 107:911-916

• Adult frogs exposed to the standard dose recommended by the World Health Organisation (WHO) showed bioaccumulation of pyriproxyfen in adipose tissue significantly higher than control animals. Baiting six times with pyriproxyfen will thus result in significant bioaccumulation.

• Other studies in fish have had similar findings.

From: Fate of pyriproxyfen in Soils and Plants; Devilliers; Toxics 2020, 8, 20; doi:103390/toxics8010020; www.mdpi.com/journal/toxics

• This study concludes that it is compulsory to study the behaviour of pyriproxyfen for a given crop in the growing conditions of a specific area to estimate whether the established pre-harvest time ensures that the residue levels are below the maximum residue level (MRL) that is the highest concentration of pesticide that is legally tolerated in or on food when it is applied under good agricultural practices. Thus, recently, EFSA proposed 0.4 mg/kg as MRL for the tomato and 0.7 mg/kg for the citrus. The fire ant program is spraying pyriproxyfen at 5g/kg. On the permit it states: Produce that is traded for human consumption which has direct contact with the bait must be washed after harvest and prior to marketing. This might not be so helpful as according to the paper by Devillers (2020), the half-life of pyriproxyfen in plants is ranged from less than one week to about three weeks, depending on the crop and the experimental conditions.

From: Effects of Pyriproxyfen on Viability and Increase of Intracellular Lipids in HepG2 Cell Line; Lamberti et al, Occup Med Health Aff 2014, 2:5

• This study suggests that pyriproxyfen is strongly cytotoxic to human hepatocytes (liver cells). This concurs with the toxicity label for the chemical which lists the general human health issues as possible liver toxicant, possible blood toxicant and endocrine issues – estrogenic effect.

From: Ultimate fate and toxicological consequences of insecticide pyriproxyfen and its metabolites in soil ecosystem; Kumari et al; 2021; https://doi.org/10.10166/j.envadv.2021.100040

• Pyriproxyfen can degrade into approximately 10 metabolites. Of six studied, their residues persisted for more than 30 days in soil with half-lives varying from 2.6 to 30 days. Metabolites C, E, and F caused toxicity to soil enzymes. Considering the persistence behaviour and toxicological consequences of metabolites, further investigations are needed for preventing their harmful effect on non-target organisms and associated environment.

From: The impact of pyriproxyfen on the development of honey bee (Apis mellifera L.) colony in field; Chen et al, 2016, Journal of Asia-Pacific Entomology

• A study by Chen et al (2016) indicates that pyriproxyfen has negative impacts on both larval and adult honey bees and royal jelly production, especially under high pyriproxyfen concentrations.

From: Indirect transfer of pyriproxyfen to European honeybees via an autodissemination approach; Kanchariapalli et al; PLoS Negl Trop Dis 15 (1D): e0009824. https://doi.org/10.1371/journal.pntd.0009824

• The argument by the program is that honey bees will not go for the baits. However, they do not have to eat the bait directly. A study of autodissemination of pyriproxyfen found that pyriproxyfen-treated mosquitoes can contaminate nectar sources, which results in the indirect transfer of pyriproxyfen to European honey bees.

Other chemicals used in fast acting baits are:

• Indoxacarb – banned in EU and China ​

• Hydramethylnon – linked to cancer by US EPA​

• Fipronil – a PFAS pesticide. PFAS are recognised as Class 1 carcinogens. Banned from outdoor use in EU.​
  ​
  The safety of deployment within metres of waterways is questionable for pyriproxyfen and fipronil. EPA in NSW has refused to do any monitoring of rivers at all.​

From: The effects of the insecticide Pyriproxyfen on germination, development and growth responses of maize seedlings; Coskun et al

• A study looked at the effect of pyriproxyfen and suggests that excessive and uncontrolled usage of pesticide pyriproxyfen results in phytotoxic effects by inducing some morphological, anatomical, physiological and metabolic processes. In addition, as chemical compounds accumulate, pyriproxyfen is thought to adversely affect all living beings feeding on plants that are exposed to chemicals, and also negatively affects the environmental factors such as soil, air, and water.

From: Environmental fate and properties of pyriproxyfen; Sullivan et al; California Environmental Protection Agency, J. Pestic. Sci., 33 (4), 339-350 (2008) DOI: 10.1584/jpestics.R08-02

• Pyriproxyfen is toxic to insects during their embryonic, last larval, or reproductive stages and is particularly effective against pests that are relatively insensitive to conventional insecticides, such as whiteflies, mealworms, scales, and thrips.

• If released in water, pyriproxyfen adsorbs onto suspended solids and organic matter and retains biological activity for up to two months.

• The low solubility, high partition coefficients, and hydrophobicity of pyriproxyfen are consistent with chemicals that are known to be environmentally persistent.

• In anaerobic conditions, such as brackish waters or sediments, pyriproxyfen is much more stable, immutable, and toxic to aquatic invertebrates.

• Given its potential to persist, prudence should be used when applying pyriproxyfen to or near water bodies, and precautions must be taken to avoid or mitigate drift or runoff to surface waters.