Dalmatian pyrethrum

Dalmatian pyrethrum (Chrysanthemum cinerariaefolium) is a daisylike perennial plant of the genus Chrysanthemum belonging to the Compositae family. The white flowersheads possess insecticide properties.
Pyrethrum originated in the Dalmatian Mountains of Yugoslavia and its cultivation spread throughout the world at the turn of the century. The colonial powers introduced it into East Africa and South America and after the First World War Japan became the principal exporter. The poisonous effects of Pyrethrum on warm-blooded mammals are so slight that it is usually regarded as harmless to male. However, prolonged contact wih the skin can produce a rash, and inhaling dust or spray can cause headaches and sickness .
The toxicity of pyrethrum preparations is considerably increased by the addition of small quantities of rotenone (e.g. derris, tephrosia, lonchocarpus) or nicotine (e.g. tobacco, anabasine) .
The effectiveness of pyrethrum is quickly reduced under the influence of strong sunlight . The addition of anti-oxidants, e.g. taneic acid (present in annona bark) slows down this process.
Substances known as synergists such as sesame oil or piperonyl butoxile enhance the utilization of the toxic suibstances in pyrethrum either by increasing or prolonging their effects. This means that insects do not recover so quickly after the knockdown effect.

Pyrethrum is used in two ways :
As a poder or dust, and as a spray. As a dust it can be used either pure or mixed with a carrier such as talc, lime or diatomaceous earth. When it is use as a spray, pyrethrum is usually dissolved in water, soap solution or kerosene. After kerosene spray has the advantage that the decomposition of the active substance is slowed down . Soapy sprays have some effects on the surface action and increa the toxicity of the pyrethrum. The spray should be applied as soon as it is prepared .
*Kerosene-extract
500 gm pyrethrum flowers are steeped in 4 litres of kerosene half a day. After straining through a or cloth the so is ready for use . It has been shown kerosene
*500 gm pyrethrum powder, 3-4 litres of paraffin.
The pyrethrum is steeped in paraffin for a day, stirred occassionnally and strained before use. This preparation has been in plantations in Kenya .
*20 gm pyrethrum powder, 10 litres of water.
The ingredients are strirred well together and applied immediately. For the best effect this mixture should be applied in evening .
*Dufour preparation
1-1,5 kg dried pyrethrum, 3 kg liquid soap and 100 litres a water are being extracted like above mentionned. The addition a soap is supposed to increase the effectivity four-fold.