Pyrethrum Pyrethrum is the most widely used botanical insecticide in the United States. Most Insects are highly susceptible to pyrethrum at low concentrations. Flying Insects drop almost immediately upon exposure. Pyrethrums are primarily effective as a contact poison. They affect the central nervous system of Insects.
Pyrethrum is nontoxic to most mammals, making it among the safest insecticides in use.
Trade names include Pyrenone and Pyrellin. Do not use products containing PBO when temperatures exceed 90 degrees F. Pyrethroids Pyrethroids are synthetic materials designed to imitate natural pyrethrum. Pyrethroids are not accepted by organic producer regulations. These synthetic materials have the basic chemistry of pyrethrins but are modified to improve persistence, insecticidal activity, etc. Pyrethroids are widely used in U.S. agriculture under trade names such as Asana, Capture, Astro, Mavrik, Pounce, resmethrin and sumithrin.