pyrethrum

/pahy-ree-thruhm, -reth-ruhm/US // paɪˈri θrəm, -ˈrɛθ rəm //UK // (paɪˈriːθrəm) //

除虫菊,除虫菊花,除虫脲,除虫草

Definitions

n.名词 noun

1
- : any of several chrysanthemums, as Chrysanthemum coccineum, having finely divided leaves and showy red, pink, lilac, or white flowers, cultivated as an ornamental.
- : any of several chrysanthemums, as C. cinerariifolium, or C. coccineum, cultivated as a source of insecticides.
- : Pharmacology. the dried flower heads of these plants, used chiefly as an insecticide and sometimes in medicine for certain skin disorders.

There are very few data at hand concerning the discovery of the insecticide properties of pyrethrum.
How anything can be gay with Pyrethrum uliginosum I cannot imagine.
An irritant substance, as Ginger, or Pyrethrum, tends especially to cause this secretion when masticated.
If the flies are very numerous, catch them in wire traps, or burn pyrethrum powder in the room.
To clean the room where there are many flies, burn pyrethrum powder (Persian insect powder).