Latin pellitory (Anacyclus pyrethrum)from Greek purethronfrompūrfire (from its warming effect)pyretic
American Heritage Dictionary of the English Language, 5th Edition
Pyrethrum Sentence Examples
Pyrethrum cinerariaefolium is exported for the manufacture of insect-powder, and sunflowers are cultivated for the oil contained in their seeds.
The pyrethrum grows best in soil of a loamy texture; this should be well manured and deeply trenched up before planting, and should be mulched in the spring by a surface dressing of half-decayed manure.
Other prominent species are Campanula, Pyrethrum, aconite, Cephaelis, speedwell, Alchemilla sericea, Centaurea macrocephala, Primula grandis and a species of primrose.
They have a similar activity to the natural compound pyrethrum, which is extracted from plants of the Chrysanthemum family.
If they are completely infested, we feel that the only safe product to use is a pyrethrum based powder.