A perennial, growing to 45 cm/18 in (Tanacetum cinerariifolium), native to parts of the Balkan peninsula, but extensively cultivated, especially in E Africa and South America; leaves divided, silvery-grey; flower-heads solitary, daisy-like, spreading outer florets white. An insecticide, known in China by the 2nd-c AD, is prepared from the extracts of the powdered and dried flower-heads. (Family: Compositae.)
Pyrethrum refers to several Old World plants of the genus Chrysanthemum (e.g., C. It is also the name of a natural insecticide made from the dried flower heads of C. cinerariifolium and C. It looks more like the common daisy than other pyrethrums. Plants have blue-green leaves and grow to between 45 to 60 cm in height. The plant is economically important as a natural source of insecticide. The flowers are pulverized and the active components called pyrethrins, contained in the seed cases, are extracted and sold in the form of an oleoresin. Pyrethrins attack the nervous systems of all insects, and inhibit female mosquitoes from biting. When not present in amounts fatal to insects, they still appear to have an insect repellent effect. Kenya produced 90% (over 6,000 tonnes) of the world's pyrethrum in 1998, called py for short. C. coccineum, the Persian chrysanthemum, is native the Caucasus and looks somewhat like a daisy. The leaves resemble those of ferns, and the plant grows to between 30 and 60 cm in height. C. coccineum also contains insecticidal pyrethrum substances used for centuries as a lice remedy ("Persian Insect Powder", "Persian Pellitory") in the Middle East, but it is a relatively poor source compared to C. Other species such as C. balsamita and C. Pyrethroids are synthetic insecticides based on natural pyrethrum (pyrethrins); A common formulation of pyrethrin is in preparations containing the synthetic chemical piperonyl butoxide: this has the effect of enhancing the toxicity to insects and speeding the effects when compared with pyrethrins used alone.
Common Names
Common names for Chrysanthemum cinerariaefolium include:
Pyrethrum Pyrethrum daisy Dalmation pyrethrum Dalmatian chrysanthemum Dalmatian Insect Flower Dalmation pellitoryCommon names for Chrysanthemum coccineum include:
Pyrethrum Pyrethrum daisy Painted daisy Persian chrysanthemum Persian Insect Flower Persian pellitory Caucasian Insect Powder Plant
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