Full explanation
The active ingredient (a.i.) is the active chemical compound in pesticides that delivers the biological effect. For example, glyphosate is the a.i. in Roundup, deltamethrin in Decis, azoxystrobin in Amistar. The a.i. concentration is always shown on the label in g/L or g/kg. Application rates are calculated by active ingredient content, not total volume. A single a.i. can be sold under different brand names with different effectiveness depending on formulation and manufacturer.