# Cypermethrin in a pressure washer



## halliwellc (Sep 13, 2012)

I have a quart of 25% permethrin concentrate and a pressure washer with a siphon hose. The rate of sucking-up on the dewalt is adjustable, but doesn't have any numbers on it, you just put the hose in the bucket and it sucks up the amount to your liking. For pest control in yard and applied to house, what is a good proportion to dilute the permethrin concentrate to a safe and effective level? (Precision's not possible, I know, b/c the rate of sucking and rate of application isn't stated, and "safe" and "effective" is all relative...but some guidance here would be helpful.)


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## Gustavas (Oct 4, 2014)

.25% or 25%????

.25 is found in many products and is pretty much ready to use.

Follow the label. 

I am assuming you are using this product and it's labeled for the pest you are trying to control, and for the site you are spraying. A pressure washer used for application is going to create a drift issue, so be careful of that. Next look on the label for how much product / sq foot you should be using.

for example here is a .25% mix:

http://www.domyownpestcontrol.com/knock-out-indooroutdoor-insect-killer-p-8697.html

and label:

http://www.domyownpestcontrol.com/msds/342052_product_label.pdf

you could put that right into your pressure washer, but you have to still be careful not to have any runoff, the label says to spray when you are not expecting rain for at least a day, and make sure not to let it drift into a stream, deadly to fish.


here is a 23% example:

http://www.domyownpestcontrol.com/permacap-cs-controlled-release-permethrin-p-2324.html

and label:

http://www.domyownpestcontrol.com/msds/Permacap label.pdf
*
you are going to want only 20-40 oz per 100 gallons....*

your product might have a similar label with directions of how much you need to water it down before it's legal to apply. 

you could run a small test:

Put 20-40 oz of water in a bucket and put your siphon in it. start spraying your pressure washer in a tub and see how many gallons of water is sprayed from the pressure washer before the 20-40 oz of test water is gone. if you are at or above 100 gallons you are good to go (with the above product label)

if you are under 100 gal of water you are going to have to dilute your concentrate before starting this job. if you were at 50 gal, you would have to cut your solution in half, 25 gal, do a 1 to 4 mix, and so forth.


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## r0ckstarr (Jan 8, 2013)

Why not just get a cheap pump sprayer? The 10$ 1gal sprayers they have at HomeDepot work fine. I have had 3 of them for a year now, and have not had an issue with them.


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