Insect Growth Regulator (IGR)
Methoprene is an IGR that does not directly kill adult insects but works on certain pests in their immature (egg, larvae) stages, thus breaking the cycle of infestations and preventing re-infestations. Immature pests exposed to this IGR simply cannot mature because they are over-loaded with a juvenile hormone mimic. If a flea larvae (for example) cannot reach adulthood, it cannot reproduce. Instead, the larvae simply dies in its immature stage. Methoprene is used in pest management programs for a variety of household and community pests: fleas, pharaoh ants, fireants, mosquitoes, cigarette beetles.
When used indoors, Methoprene (the active ingredient in Precor, Precor 2000 and others) will prevent the egg and larvae stages of fleas from developing, with a 3 to 7 month residual. Use alone for prevention or tank mix with an approved insecticide for existing problems. Precor also works on Cigarette Beetles; other pantry pests can be controlled by using Hydroprene (Gentrol), another IGR. Methoprene (or Precor) is not photostable (except in granular products such as Extinguish Fireant Bait and Methoprene Mosquito Granules) and is for indoor use. Available in liquid concentrate and aerosol formulations. Methoprene is the "Plus" in Frontline Plus for Dogs and Frontline Plus for Cats.
The use of Precor in elimination of heavy flea infestations has resulted in far less insecticides being used in homes and schools. Using Precor 3 to 4 times each year prevents homes and schools from becoming flea infested. If a female flea does enter a structure that has been treated with Methoprene (Precor,) she will not be affected by the IGR - but the 300 to 500 eggs she might lay will never become adult fleas!
When used outdoors, Methoprene helps in the spread of fireant colonies in an ant bait used in pastures: Extinguish Fire Ant Bait. Grazing animals cannot be exposed to most pesticides but Extinguish Fire Ant Bait (containing Methoprene) is safe to use in such graze lands.