Permethrin breaks down quickly when it comes into contact with our skin which is why humans don't have any issues with it. It's best used by treating the outmost face of outer layer clothing. Bare skin is best protected with a deet product.
Permethrin interferes with an insect's nervous system and can even cause death in some insects (ticks). Deet interfere's with a predatory insect's ability to sense carbon dioxide and body odor and acts purely as a repellent.
It's effective against practically any kind of insect. Spiders and fleas are rarely included on product labeling but permethrin acts to ward them off/kill them too.
Another thing to keep in mind is that permethrin is highly toxic to cats and if over applied can harm other animals too including dogs. So the safest bet it to store treated gear away from housepets and to use care when applying while following reliable treatment instructions to the letter. (AKA more is not better it is dangerous to household animals)
If you're allergic to chrysanthemums, you may find that permethrin causes hay fever or skin irritation. But as I understand it those are generally considered extreme reactions even amongst those who are allergic. Most people don't have any issues.
That should cover most of what you need to know.
Good job on the math yardman! Permethrin is a very safe insecticide (IMO), as I deal with much more potent stuff all the time. I must add that the link is only one brand of the permethrin. Anyone should be able to find this stuff and make their own. I really dislike skeeters, ants, spiders, and the like and knowing we can lower the problems so easily is cool.
Firstly, I apologise for the metrification. I cant be bothered converting and its all the same math, but I digress....
Ok, so I want to treat my hiking gear and my clothing for field archery in permethrin soak.
Im tired and I dont want to mess up the math, so Im not gunna do this until one of you nice people can help.
I have a 25gram sachet of 250gram/kilogram permethrin 25:75 powder.
Dr Debs soak http://www.thetraveldoctor.com.au/permethrinsoak.pdf
Is 500grams per litre, made up for use at the rate of 20ml into .6 to 1.75 litres of water depending on the item to treat. (see link)
My reckoning says that at 250g/kg, 25grams of powder = 6.25grams of permethrin.
Dr Debs is 500g/litre, with a 20 millilitre dose into say 1 litre of water.
So 20ml at 500g/litre = 10grams of permithrin, into 1 litre, makes the recommended dosage.
So if 10grams go into 1000ml, the ratio is 1gram of permethrin to 100millilitres of water.
So if I mix my sachet with 625 ml of water, I have the correct soaking dosage for my mosquito net/ hammock.
Diluting the 10/1000 solution remaining to 10/4000 by volume will give me the correct dose for my clothes. According to Dr Debs mix.
All is good, I think.
I dream of a better tomorrow, where chickens can cross the road and not be questioned about their motives.
I have another question...
I'm planning a hike for the scouts to the Neusiok trail the end of march. The last time we went there, we were infested with ticks. Can I make up some of this into a spray bottle and spray the scouts gear (backpacks, boots, clothes) with it, on the day of the hike?? Not enough to soak, but just a light spray to keep the critters off??? Hoping this will work because none of the scouts will have their gear treated beforehand.
great, thanks for the info. I can spray the gear when we pack it into the car and it can dry while we're driving to get to the trail.
I cant say I have ever tried it, but I would worry about a horrible smell if you sprayed a ton of gear and put it in a car wet. (not to mention possible health issues with all that vapor trapped in a confined space)
Tina, it's one thing to buy pesticide at a feed store and use it on yourself, but quite another to hose down someone else's children with it. I don't know the solution to this conundrum, but it's certainly something to think about.
It may not be rocket science, but it's still science.