The interesting world of pyrethrin biting-insect control

Note that these pyrethrin vaporizers are not recommended for long term use in rooms with poor airflow where cats are present. Cats may have greater sensitivity to the vapour than humans, so if they show odd behaviour then discontinue use of the unit. I'm finding mixed results on this subject - it may be direct ingestion of the liquid that poses the main hazard.

Thousands of years ago, it was discovered that a specific type of chrysanthemum plant had the effect of interfering with the nervous systems of insects and could be used to protect crops. The plant was cultivated, processed and the resultant powder was sold as an early insecticide.

With modern technology the original pyrethrins have been replicated and in some instances modified to make them more effective.

These devices use resistively heated ceramic rings to evaporate a carrier oil from a wick in a slow and controlled manner using just a few watts of power. They are very similar to the common household aroma plugs that evaporate a carrier with aroma chemicals.

The plug-in vaporisers are common in places like India, China and other countries with a mosquito problem. But they also work in countries where other biting insects like midges and no-see-ums are a nuisance. The pyrethrin vapour affects the insects nervous system and acts as a deterrent or disables the insects while in that area.

The contents of the bottles are usually about 1% prallethrin or transfluthrin in an excipient (carrier) oil like very refined odour free kerosene or isoparaffin.

Power consumption of the plug-in or USB vaporisers is usually around 3W. The units are mostly used at night when the biting insects are most active.

These units are considered safe for large mammals like humans, especially at the tiny amounts in the air. But the bottles should be kept away from kids and pets who may try to ingest the contents. There is also a risk that cats have a lower tolerance to pyrethrins, so they should not be exposed to the vapour for long periods of time.

If you want to know more about pyrethrins then here are some good Wikipedia articles as a starter.
https://en.wikipedia.org/wiki/Pyrethrin
https://en.wikipedia.org/wiki/Prallethrin
https://en.wikipedia.org/wiki/Transfluthrin

If you want to explore pyrethrin oils and vaporisers then here are some links to them on AliExpress (not a sponsor). These are affiliate links, but that will not affect the price you pay.

The bottles of oil and prallethrin:-
https://s.click.aliexpress.com/e/_c3E0h5r3

A USB powered heater unit:-
https://s.click.aliexpress.com/e/_c4aJQmrB

Various style mains heater plugs:-
https://s.click.aliexpress.com/e/_c3fuT53F

As usual with AliExpress, once you show an interest in something, other items will pop up, including in the bundle deal section.



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