Pyrethrum seed Chrysanthemum

LATIN NAME: Tanacetum cinerariifolium

COMMON NAME: Dalmatian Pyrethrum

Walk past the pyrethrum in full flower and the daisies look gentle enough, but the whole plant packs a fine, sharp wallop for the insects. The low, upright, perennial plant carries the finely cut, feathery, grey-green leaves and the many white, daisy-like flowers with the yellow centres through the summer, and the dried flower heads have a very long record as the plant pest powder of the old gardens. The plant is a fine, bright presence of the border and the herb garden. It is a plant of the open, sunny, well-drained ground.

Scientific Research & Plant Biotechnology

The pyrethrum is a useful, studied subject of the plant science, looked at for the fine, sharp compounds of the flower heads. The chemistry of the dried flower heads, which have a very long record as the natural pest powder, has been studied at length, and it keeps showing up in the work on the natural insecticides, the bio-pesticides and the members of the daisy family. The feathery leaves and the low, upright habit have also made it a fine garden plant, and the pyrethrum is a regular subject of the studies of the insect-repelling daisies of the warm world.

Ecological & Economic Value & Wide Applications

The pyrethrum has a long, practical record in the garden and the trade. The white, daisy-like flowers open through the summer, and the dried flower heads have a very long record as the fine, sharp pest powder of the old gardens and the modern natural crop care, breaking down fast in the light and the air. The plant is a bright, generous presence of the border and the herb garden, drawing the bees while the powder keeps the pests at bay. It has been written about in the agricultural and the environmental papers for the natural pest ways and the long record of use, and it is a fine, useful plant of the open, sunny, well-drained garden.

The pyrethrum is one of the long-flowering daisies of the herb garden, and the white heads with the yellow centres draw the bees through the summer. The finely cut, feathery leaves keep the plant neat through the season.

To grow the pyrethrum from seed, sow the small, grey seeds over the surface of a tray of fine seed compost, pressing them in lightly, keep the tray in a bright, warm spot and water gently. The seedlings appear within a couple of weeks and grow on steadily. With the sun, the warmth and the well-drained ground, the white daisies will open through the summer.

Chrysanthemum cinerariifolium – Pyrethrum

C. cinerariifolium is called the Dalmatian chrysanthemum, denoting its origin in that region of the Balkans (Dalmatia). It looks more like the common daisy than other pyrethrums. Its flowers, typically white with a yellow center, grow from numerous fairly rigid stems. 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. This is applied as a suspension in water or oil, or as a powder. 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. They are harmful to fish, but are far less toxic to mammals and birds than many synthetic insecticides and are not persistent, being biodegradable and also breaking downeasily on exposure to light. They are considered to be amongst the safest insecticides for use around food. Kenya produced 90% (over 6,000 tonnes) of the world's pyrethrum in 1998, called py for short. Production in Tanzania and Ecuador is also significant.

Insecticides
SpraysPyrethrum was used for centuries as an insecticide, and as a lice remedy in the Middle East (Persian powder, also known as "Persian pellitory"). It was sold worldwide under the brand Zacherlin by Austrian industrialist J. Zacherl.

The flowers should be dried and then crushed and mixed with water. It should be noted that though the pesticide is organic, it can still be harmful to humans.

Pyrethroids are synthetic insecticides based on natural pyrethrum ( pyrethrins ); one common example is permethrin. 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. These formulations are known as synergized pyrethrins.

Companion planting
Because of the natural insecticidal properties of the pyrethrums, they are used as companion plants, to repel pest insects from nearby crops and ornamental plants. They are thought to repel aphids, bed bugs (cimex lectularius), leafhoppers, spider mites, harlequin bugs, ticks, pickleworms and imported cabbage worms, among others that are in gardens and farms. For example, they are planted among broccoli plants for protection from several common insect pests.