Robert's Rants
Robert's Rants
A personal blog on the Canadian pesticide industry and other pet peeves and interests

Could FMC and the PMRA get the label rate right? I’m buying Prelude

In my on-going assault on stupidity, and basically how to make a label an unusable document, let’s do some quick math on the correct label rate.

So as you remember after using Dragnet for 25 years, the rate for permethrin is and always has been 0.5% solution. Except termites.

And their label has said put 50 mils in 4 liters of water (your common B&G size).  Or like todays label, 25 mls in 2 liters (your common pop bottle size – and don’t be idiotic, never use any other container to put a pesticide in)

Or 12.5 mils of product per 1 liter.


So let’s go back to our 7th grade math class

25 mils / 2000 mils = 0.0125 or 1.25% dilution.  But wait!  The product only has 384 grams of active or 38.4%.

So 1.25% X (times) 0.384 =  hmmm…. 0.48% instead of .5%?  So my rate is short  

All these years and I’m under-dosing!  Guess I should have used 26 mils, but that’s off label.  Kinda.  Sorta.

But here’s the best one, and I swear this is on their label…multiple times.

When you mix 2 liters use 25 mils but when you mix 10 liters use….wait for it….130 mils.

What??????  (That should really should be WTF???? but I’m trying to clean up my act)

On one spot you say to use 12.5 mils per liter, but right next to it you say to use 13 mils per liter.

So which is it???

Maybe it doesn’t matter.

Prelude states use 42 mils of the 24% product in 2 liters of water to get 0.5% solution.  And guess what?!?   It really is 0.5%!

So when Cait, the PMRA inspector, swabs your tank and says you’re only using 96% of the label rate, tell her that’s exactly right and give her the 800 number for the Ottawa office.

Or switch to Prelude.

And they hold us accountable.