Do insecticides expire?

Q: Do insecticides expire? 

A: A lot depends on how they were stored. If they were kept cool and in a dark place, I’d give liquid products at least three years, maybe five years, of effectiveness. The product form also is a factor. Dusts and wettable powders are much shorter-lived than liquid emulsifiable concentrates. I’d give dusts and wettable powders only two years before disposing of them.