nPyrethrin(Chem) A substance resembling, and isomeric with, ordinary camphor, and extracted from the essential oil of feverfew; -- called also Pyrethrum camphor.
Century Dictionary and Cyclopedia
npyrethrinA resinous compound found in pellitory resin from the root of Anacyclus Pyrethrum.
Webster's Revised Unabridged Dictionary
NL. Pyrethrum, generic name of feverfew, Gr. feverfew
Research out of Ohio State finds foggers have little impact on modern-day bed bugs due to the brief exposure times, their relatively low concentrations of pyrethrins and/or pyrethroids, and their lack of residual activity.