DIY - Make your own Permethrin Mosquito Yard Spray

Making your own Permethrin based mosquito spray good up to 30 days – using an Orthro Dial’nSpray and 10% Permethrin solution. I had previously used a Permethrin based spray from Cutter Backyard Free to keep down the mosquitoes in our yard. We are in a heavily wooded area and the commercial Permethrin based hose spray worked well for us. It usually kept the mosquito population to almost 3-4 weeks depending on the amount of rain we had. For the most part this made our yard usable during the summer. These sprays have become difficult to buy, so I figured why not make my own.


As best I can tell Permethrin properly applied is a safe mosquito reduction chemical. So I decided to make my own using commonly available Ortho Dial n spray and 10% Permethrin used for cutting down pest in animal barns. I found the 10% Permethrin for $14.44 from Amazon or (see 8/30/2016 update below for more economical 36.8% Permethrin solution).

I just needed to figure out the proper dilution and delivery rate for the dial n spray. The Permethrin I bought recommended ½ oz of 10% spray for 3 gallons of water to cover 1000 sq ft. I did the math to upsize this to cover 5000 sq. ft. of lawn and fill my Ortho dial n spray (new model) (32 oz capacity).

Tools:

• Garden hose and water supply
• 1 – 32 oz Ortho Dial n Spray
• 1- 32 oz 10% (or 36.8%) Permethrin solution (any brand)

Mix:

• Add 2.5 oz 10% Permethrin in the dial n sprayer container
• Fill the remainder of the dial n spray with water (creates 32 oz water and Permethrin solution –properly diluted to instructions)

						Ortho Dial n Spray Setting
Permethrin strength	Permethrin fl oz	Dilution ounces	Gallons of Water Mixture	sq ft yard coverage		oz per gallon	tablespoons per gallon
10%	2.5	30	15	5000		2.00	4.00
36.8%	0.7	30	15	5000		2.00	4.00

Application:
Set the dial n spray to apply at a rate of 2 oz per gallon. The previous Cutter solution recommended applying the solution when it was wet out. So I usually wet the area before I spray with the hose (no solution). Once it’s wet I spray the solution over the wetted grass, weeds, under our deck, and the shady corners of our porch with the dial n spray set to 2 oz per gallon.

I did my first spray on June 4th and I can tell it’s time to spray again. They were really cut down for the last month. The mosquito population has just started picking up again. Based on the rate of usage I should get 12 applications a year for $15. I think that’s a pretty economical way to enjoy your backyard again.

As with any chemical, be sure to read the directions thoroughly. Be careful in what pesticide you apply and use it sparingly, so as to minimize any impact on the environment.

Hope this blog post makes your backyard more livable for the summer.

UPDATE 2012-06-01:
It would appear that the Ortho Dial n spray design has changed and doesn't work as well as a hose sprayer. The Chapin G362 Professional No Pre-Mix Sprayer seems to get good reviews on Amazon and should work the same way -haven't tried it my dial n spray (old design) is holding up well. It has a 16 ounce container vs the 32 ounce of the Ortho sprayer). To compensate, just set the Chapin model to "4" which delivers 4 tablespoons per gallon.

UPDATE 2016-08-30:
Prices on the 10% solution on Amazon have gotten expensive and many retailers seem to be selling the 36.8% at the same price. Technically that's around 75% less for the same chemical. I would now recommend a quart of the 36.8% Permethrin solution as this seems to be better priced and widely available. Buy whichever is concentration or brand is cheapest. I added the updated dilution rates in the table above (0.7 ounces of 36.8% solution).