Pyrethroids 101

Pronounced “py-re-throid,” these ingredients are found in many commonly used consumer home and garden pesticides for treating problems with mosquitoes, caterpillars, ants, spiders, garden worms, wasps, cockroaches, aphids and other insect infestations.


Pesticides represent one of several ways to control household and garden pests. Most insecticides – the name for pesticides used to control insects –contain pyrethroids. As is the case with any product, all pesticides must be used properly and judiciously to minimize impact to the environment.


Insecticides with pyrethroids are used to control a wide range of insects that can infest gardens and enter the home. Chances are you are probably using a pyrethroid if you have selected a consumer pesticide product intended to control mosquitoes, caterpillars, ants, spiders, garden worms, wasps, cockroaches, aphids and other insects that threaten plants, home or health.

While you won’t see the word “pyrethroid” as a listed ingredient, they are contained in products with the following active ingredients (often ending in “thrin”)

  • Alpha-cypermethrin
  • Beta-Cyfluthrin
  • Bifenthrin
  • Bioresmethrin
  • Cyfluthrin
  • Cypermethrin
  • Deltamethrin
  • Esfenvalerate
  • Fenpropathrin
  • Fenvalerate
  • Gamma-Cyhalothrin
  • Lambda-Cyhalothrin
  • Permethrin
  • Resmethrin
  • Tefluthrin
  • Zeta-Cypermethrin

Protecting Our Environment

We care deeply about the need to protect our water and environment. This web site was developed out of a commitment to ensure that our products are used properly around the home and garden.

If you are a gardener or homeowner who chooses to use pesticides, we urge you to apply them responsibly. By following a few simple rules found on this site you can play an important role in preserving water quality and the environment.

Tips for Pyrethroid Use

Homeowners and gardeners who choose to use pesticides to control insects
in their yards should adhere to the following guidelines:

  1. Always read the entire label first and follow the directions
  2. Reduce pest infestations by eliminating what often attracts them or creates ideal breeding conditions – standing water, pet droppings, tree prunings or fallen fruit
  3. Remove thatch buildup in lawns to ensure water soaks deeply into the lawn and prevents runoff
  4. Mix and use only the amount you need
  5. Avoid applying a spray or dust on a windy day
  6. Rinse all pesticide application equipment only over the treated area
  7. Always use dry sawdust or kitty litter to soak up a liquid spill and then sweep it into a plastic garbage bag for disposal; don’t use water to rinse or clean up a liquid spill
  8. Sweep or blow granules that fall on porches, driveways and sidewalks back onto the treated area
  9. When watering treated areas, don’t overwater and don’t allow water to runoff into gutters, in-lawn drains or storm drains