What is the strongest likely PERMETHRIN concentrate available on the bazaar today? I have a stable and a trillion flies, how do i get...

I have a stable and a trillion flies, how do i get rid of them?
Why does my catnip sometimes die bad?
Answers:    No, it's not the strongest!! That thinking doesn't work and ends up within the insect becoming resistant to the chemical.

http://www.ipm.ucdavis.edu/PMG/PESTNOTES...

read: repeated applications during fly season