Synergists per se are not insecticidal but rather enhance
the activity of insecticides by inhibiting their metabolic
degradation. Components of the cytochrome P-450 system
are responsible for the oxidative metabolism of numerous
insecticides, and these enzyme systems are inhibited
by synergists. With fast knockdown chemicals such as
the pyrethrins, allethrin, and resmethrin, synergists
enhance insecticidal activity by prolonging the period
of knockdown. Synergists also improve the safety of
insecticidal formulations because their presence permits
comparable efficacy to be achieved with lower doses of the
active ingredient.
