Permethrin Insecticide Information

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Permethrin is both an insecticide and a repellent, so it both kills and repels ticks and mosquitoes. Permethrin is a pyrethroid. Pyrethroids are synthetic chemical insecticides that act in a similar manner to pyrethrins, which are derived from chrysanthemum flowers. Pyrethroids are widely used for controlling various insects and are commonly used in mosquito control programs to kill adult mosquitoes

All pesticides sold or distributed in the Unites States must be registered by the Environmental Protection Agency (EPA), based on scientific studies showing that they can be used without posing unreasonable risks to people or the environment. Permethrin has been registered by EPA since 1977. It is currently registered and sold in a number of products such as household insect foggers and sprays, tick and flea sprays for yards, flea dips and sprays for cats and dogs, termite treatments, agricultural and livestock products, and mosquito abatement products.

DisclaimerThe decision to use an insecticide should be made based on an individual’s determination of the risks versus the benefits of insecticide application. Permethrin, like most pesticides, is a broad spectrum pesticide. However, it has a short half-life and does not have long-term residual effects. 

Many people in Fairfax County have a very serious problem with the Asian tiger mosquito (Aedes albopictus) and are unable to use their yards because of this pest. This is when the homeowner must weigh the decision of their quality of life versus the use of the adulticide.We do not support the injudicious use of pesticides. We mention permethrin use as a part of a combined or integrated approach to help reduce mosquitoes and ticks around the yard.

Using Permethrin

Always read and follow the label instructions before applying insecticides.

  • Personal Protection
    • Permethrin should always be applied according to the label.
    • Formulations to protect against mosquitoes and ticks should not be applied directly to the skin.
    • Certain permethrin-containing products are recommended for use on clothing, shoes, bed nets and camping gear.
    • Clothing and gear may also be purchased pre-treated with permethrin.
    • Items treated with permethrin retain the repellency and insecticidal effects after several washes. Re-application of this product should always be done in accordance with the product labeling.
    • Permethrin is the only pesticide registered to pre-treat fabrics, which the Armed Forces Pest Management Board (AFPMB) strongly supports as a method of preventing many diseases that might afflict military personnel in the field.
    • Permethrin is also used to control head lice and scabies. Only the formulations for the control of these two arthropods may be applied to the skin — always check the label to ensure proper use of an insecticide.
  • Protecting Your Yard
    • Applying a permethrin barrier spray to your yard will provide temporary relief from biting adult mosquitoes.
    • Permethrin also helps to effectively control ticks in your yard.
    • Spraying a barrier at the edge of your property and areas where vegetation is thick is most effective. Avoid spraying flowers, herbs, vegetables or butterfly gardens.
    • The person spraying the yard should be able to read pesticide labels, understand how to correctly mix the pesticide (if necessary), and follow the listed precautions in handling and applying the material.
    • The correct protective gear, as listed on the label, should also be used when applying any pesticide.

Does permethrin pose a risk to human health?

According to the EPA, permethrin can be used for public health mosquito and tick control without posing unreasonable risks to human health when applied according to the label. Permethrin is considered to pose slight risks of acute toxicity to humans. At high doses, pyrethroids may affect the human nervous system. According to the Agency for Toxic Substances and Disease Registry, permethrin has been used for many years with no human poisoning cases reported. No indication exists that permethrin has a significant adverse effect on humans when used as recommended. However, it has induced skin sensations such as tingling, pricking, and numbness in exposed workers, but these effects disappeared within 24 hours.

Does permethrin pose risks to wildlife or the environment?

  • Permethrin, when applied at mosquito control rates as listed on the label, is low in toxicity to mammals, and is practically nontoxic to birds. Mosquito control formulations of permethrin break down in the environment, and high temperatures and sunlight accelerate this process.
  • Permethrin is toxic to fish. For that reason, EPA has established specific precautions on the label to reduce such risks, including restrictions that prohibit the direct application of products to open water. Permethrin is also highly toxic to bees, and possibly other beneficial insects. When used correctly permethrin provides a strong repellent effect and should pose little risk to these insects.
  • "The [EPA] also assessed the significance of permethrin use, and conducted a risk/benefit balancing analysis. Given the significance of the use of permethrin and the mitigated nature of the risks of permethrin, the [EPA] believes, on balance, that the benefits of permethrin outweigh the risks." Permethrin Facts (Reregistration Eligibility Decision (RED) Fact Sheet), EPA (EPA 738-F-06-012, June 2006 PDF icon)

Links for additional information on the use of permethrin and insecticides

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