How to tell if your Prodiamine 65 WDG is still good?

[northeastlawn]

I thought I read somewhere that Prodiamine 65 WDG goes bad and isn't effective after a few years. Is this true?

and if so, is there anyway to tell what year it was made from container?

I have a jug of it I have been using for 3 years, I hate POA-A more than buying another jug :-)

[MorpheusPA]

DYO states "3 years from date of purchase," but that's the default answer for any chemical. I found an online source from Syngenta that states "at least three years." Which still seems far too trim.

If it's any consolation, I just finished the last of my old Prodiamine at age 5, garage-stored, and noticed absolutely no degradation in effect. Storage was sealed in plastic, so dry and dark, but with temperature variance. I use this to suppress weeds on the patio as well, so I'd definitely notice if it weren't working. That thing is a weed pit without it.

In practical terms, as long as you keep it dry and out of full sunlight, I wouldn't expect much of a limit (although I'd probably say 10 years if you pressed me just to be realistic).