Permethrin is a synthetic insecticide based on pyrethrum.

"Permethrin ("per-meth-rin"), on the other hand, is a synthetic, man-made insecticide, whose chemical structure is based on natural pyrethrum. The so-called pyrethroid insecticides were developed to match or exceed the effectiveness of natural pyrethrum but be more stable in sunlight".

The above is a quote from a website on permethrin to which I can't seem to post a link 😕.