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Pyrethrum Questions

Laura, from Argintina, asks about pyrethrum....

Hello, I am Laura M. from Argentina.

I m a student and I need to prepare an inform in order to  received my universitary diplom. Im not very good writing or speaking English, because of that, pls sorry for my mistakes.

My universitary teacher required me, that I have to research about a pesticide that calls "pyretro natural" (the tree is pelitre ? or pyrethrum plant and the floweheads is used to make probably de best natural pesticide available)

I understand that it is a tree or plant that some enterprises use to make a pesticide.  I have to simulate that I import that product but I cant because a dont have information about the origin, how much is the cost, where or who can provide me some information about this subjet.  Pls, I need your help.

My e-mail direction is:  (xxxxxxxxxxxx)

I hope you can help me as soon as posible.


Laura M.

To which we replied...

Hello, Laura:

Will try to help.  Don't worry about your English - I can figure it out.

Pyrethrum, I think you're referring to, is a derivative of the chrysanthemum flower.  As far as I know, it is a special kind of chrysanthemum (usually, but not always, Chrysanthemum  cinerariaefolium) flower that is grown mostly in Africa, Tanzania and Ecuador.  You wouldn't use a regular chrysanthemum flower as it doesn't contain enough of the active ingredient.  The term "pyrethrum" refer to the powder made with the dried flowers of the chrysanthemum, whereas the term "pyrethrins" refer to the six insecticide components that occur (naturally) in the powder form. These six pyrethrins constitute only about 1% of the dried flowers.  Another word you will encounter is "pyrethrums," the common Latin name used for ornamental varieties developed from the less desirable Persian Chrysanthemum.

Pyrethrum is expensive.  Not necessarily to manufacture, but to import.  Probably in Argentina as well as in the USA.  The reason is because of the problems in Africa these past few years, the internal strife within the African producing countries has reduced the total yield to a point where the finished product has been expensive.  Kenya and Rwanda are the main producers, and exports from these two countries have been reduced by more than half for the past several years.

Pyrethrum, by itself, is not really a good insecticide.  Pure pyrethrum does have an almost 100% "knockdown effect" - but as many as 75% of the insects knocked down will survive.  To be really effective it has to be mixed with a synergist or two.  The synergist acts as a catalyst to increase the effectiveness of the product.  Synergists differ, somewhat, from catalysts in that they are also an "active" ingredient, whereas catalysts usually do not change the formulas, they augment the ingredients without changing them.

With a synergist, usually piperonyl butoxide (and/or) n-octyl bicycloheptene dicarboximide, it is very powerful - and has a pretty good "killing action," without being very toxic to warm-blooded animals.  It does not have a very long residual action.  That is to say, that a short while later, (minutes, sometimes) it's gone.  Certain oils, canola is one, can also act as a synergist, as can applications performed at dusk.  Pyrethrum is much more effective at night, without light.  Almost every insect will be paralyzed by this potent combination.  It lasts no longer than 24 to 48 hours.

As an insecticide, that can be good and bad.  If you use it with that in mind, it can be a good tool for the exterminator or farmer.  If, however, you need it to PROTECT something against insects, it's not a good tool because it won't last long enough to give any benefit.  But if you have to use it around food crops, it can be a good tool because it's gone before the food product reaches the consumer.

Unfortunately, for the Africans mostly, science has now turned to developing synthetic pyrethrum, in the process turning a so-so natural insecticide into even more powerful combinations by using chiral (handed molecules) to build synthetics.  Synthetics (pyroids) are sometimes thousands of times more powerful for insects, keeping the same low toxicity for mammals.  

The major effect (immediately observable, on humans) of pyrethrum and their synthetic counterparts are inflammation of the mucus membranes, called paresthesis.  With the synthetics, the symptoms are even more pronounced:  difficulty breathing, coughing, tingling skin, eyes water, and sometimes a funny taste in the mouth.  All of these are temporary, wearing off in a few hours, or at most, overnight.  There is no effective treatment for these temporary symptoms.  If you are not prepared for the effects, it can seem scary.

As to the major exporters, you should try in Kenya - they have the most advanced systems of export.  Several producing companies have web sites, let me know if you can't find them and I'll see if I can get some addresses for you.

I hope I have answered some of your questions.  Please let me know if you have any more.


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