Natural pesticides: Pyrethrum
August 19, 2010 § Leave a comment
Pyrethrum and permethrin are broad range insecticides which control aphids, whitefly, beetles, caterpillars, leaf hoppers and other insects.
Pyrethrum is an insecticidal compound which naturally occurs in some chrysanthemum flowers. The variety Tanacetum cinerariifolium can be grown in the home garden and then dried and powdered with care and dusted on plants and on the soil around plants.
Pyrethrum is unstable in sunlight, lasting only about 12 hours, so must be applied daily with great care to avoid inhalation.
Permethrin is a man-made insecticide whose chemistry is based on natural pyrethrum. It was developed to be stable in sunlight for up to 30 days. Permethrin is used in head lice shampoos, flea, tick and mosquito control on dogs and mosquito control on outdoor clothing and camping gear. It is highly toxic to cats, bees, fish and a small number of beneficial insects.
Synergised pyrethrums use the naturally occurring pyrethrum compound but it is bonded to piperonyl butoxide to stabilise it.