ticks in your gear while you’re in the bug bivy?

On my last trip to a Ca coastal area I purchased a bottle of Sawyer's Permethrin for around $8 and it worked very well to kill a couple ticks we found.

However, you can get a large bottle of concentrate and make gallons upon gallons of spray for much much cheaper. This is a 32 oz bottle.. some reviewers recommend 1-2oz per gallon, so you can get at least 15 gallons or so out of the concentrate, which should be good enough for years of backpacking treatments.

http://amzn.com/B003IMO3I2

>"you can get at least 15 gallons or so out of the concentrate, which should be good enough for years of backpacking treatments."

At which point it's worth asking how shelf stable this stuff is. Does anybody know if stored permethrin loses its effectiveness over time?

"At which point it's worth asking how shelf stable this stuff is. Does anybody know if stored permethrin loses its effectiveness over time?"

A cursory Google search points to 3-5 years if it's stored in non-extreme temperatures or environments.