NyGuard's active ingredient is Pyriproxyfen, an Insect Growth Regulator (IGR), which is a juvenile hormone mimic (JHM). The naturally occurring juvenile hormone regulates and stimulates the developmental process of insects. High concentrations of juvenile hormone stimulate the molting process. The level of juvenile hormone then drops to low levels, which leads to normal maturation of the larvae (larva to pupa, pupa to adult, or nymph to adult molt).

NyGuard interferes with this synchronized balance of hormones during the molting process. Treatment with NyGuard introduces and maintains high concentrations of juvenile hormone mimic at critical points during the insect developmental process. Thus, normal maturation of larvae or nymphs is prevented. The result is the insect stays in an immature stage indefinitely. When this happens the insects with complete metamorphosis will continue to molt from larva to larva until it dies. Insects with incomplete metamorphosis will remain in nymph stage, or have morphological deformation, maturing into sterile, non-reproductive adults.

NyGuard disrupts the normal metamorphosis process of immature insects. Treatment with NyGuard will disrupt the growth, development and reproduction in many insect species in a manner that is environmentally acceptable. The biological results in the target insects are most commonly death or deformity with sterility.

NyGuard does not kill adult insects. For best results, use NyGuard in combination with an insecticide that will kill existing populations of insects. Once the active insect populations have been eliminated, NyGuard will remain to disrupt the maturation of eggs or other immature stages of the insect population.