Pyrethrum is the most effective natural insecticide on the planet. It is also a most versatile and cost effective insecticide available even when you compare it with the modern synthetic insecticides.

And, its toxicity to mammals is so low as to be almost inconsequential. Not that it doesn't have a dark side. It does. Natural pyrethrum can cause allergic reactions in some people. Sneezing is perhaps the first noticeable symptom. If you get allergic reactions to it, stay well out of the action. Don't use it. Sorry, the great advantages of pyrethrum are not for you.

101 uses? When you multiply the number of insect pests pyrethrum controls by the number of places and situations you can use it… there are thousands of uses!

Pyrethrum is an insecticide and miticide that kills by contact. Whether it hits them as a droplet, is picked up as they walk over a recently treated surface or they eat a sprayed leaf… the pyrethrum attacks their nervous system and they die.

Secondly, pyrethrum is repellent to most insects. At levels mammals can't measure, insects, such as bees, can ascertain the presence of pyrethrum and they stay well away.

Thirdly, pyrethrum has a short residual life. This is a really important advantage. It breaks down in ultra violet light. There is no long term contamination of surfaces or areas. The kill of all the insects contacted reduces the infesting population to almost nil and it takes time for another population build up. A long residue is of no advantage on plants anyway; new leaves appear every other day and insects seldom eat old leaves when new and tender shoots are available.

Here are some of the main categories of uses…
Flying insects
(Flies, mosquitoes, midges, moths, ferment flies, beetles, aphids, leafhoppers etc.)

Pyrethrum diluted in light oil or emulsified in water and dispensed as a spray, mist, fog or aerosol is aimed at the pests. Impacted by a droplet or two... they die.

Repellency is an important factor if you are organising a BBQ or other outdoor function. If you spray/fog all the surrounding foliage and buildings, you will kill all the mozzies and Sandfly/Midges and the area becomes repellent to new insects. It could be hours before the first bite!
Crawling insects
(Cockroaches, ants, caterpillars, spiders, mites, etc.)

Liquid formulations of pyrethrum sprayed into crevices or on the under surfaces of leaves will kill hiding insects. Powder formulations have been used for a hundred years to control fleas, lice and ticks on dogs, etc… (not cats, which lick their fur).

Bed bugs

Even though we know that it will kill every insect it has been tested on, we are not allowed to make any claims about Bed Bugs (a lucrative industry), so we don’t, but we do sell heaps to Back-packer hostels, but can’t say what for - courtesy of Australian Pesticides and Veterinary Medicines Authority.

Repellents
Apart from the examples of the bees and BBQs already given, pyrethrum solutions wiped over the coats of horses, cattle, goats and dogs can give them relief from biting insects. Some years ago, dairy farmers increased milk yields considerably by repelling the annoying biting flies. This was done by spraying the herd after the morning milking. Beef cattle feedlots could increase their beef production during those couple of months when biting flies reduce weight gain. 1 extra kg of prime beef a day times 10,000 steers is a lot of money!

Repellency also works on packaging. Varnishing the outside of paper and cardboard food packages was once a common practice to repel weevils and flour moths.
Protectants
Pyrethrum in a grain mass will protect against weevils and other grain eating insect pests for 3-6 months. It can protect your precious seeds from insects that just love to eat the embryo first. The residual life is longer because the pyrethrum is down in and mixed with the grain away from ultra violet light.
Plant pests
Flower, fruit, vegetable and ornamental plants are almost always attacked at some stage by aphids, thrips, bugs, hoppers, mites or leaf-eating caterpillars and beetles. If you can contact them by liquid or dust formulation of pyrethrum they will die. Because of the ultra violet sunlight, there is no residue next day and the crop is safe to harvest from then on. Pyrethrum is not a systemic so it will not enter or be circulated around the sapstream to kill sap-sucking insects such as scales or fruitfly larvae and gall-formers inside the plant. Crop yield increases by much more than the cost of the pyrethrum and its application.
Other uses
If you are into making soap, adding pyrethrum will give you an insecticidal soap to wash dogs. You can add it to wax as well as or instead of citronella to use as an insect repellent BBQ candle.
Pyrethrum and pyrethrins?
What's the difference? Pyrethrum is the name of the chrysanthemum family plant and the name used to describe the insecticidal goo extracted from it. The refined extract contains Cinerins 1, Cinerins 2, Jasmolin 1 and 2, Pyrethrins 1 and Pyrethrins 2 as the insecticidally active components.

Because the pyrethrins is the only bit that does the work, it is the active ingredient listed on the labels of registered formulations.

If you are spraying on your plants outside under direct sunlight it is best to spray late in the day so it works through the night & breaks down in the light of the next day. So store in a dark place, mister too.