Gentrol IGR Concentrate Zoecon Growth Regulators (IGRs) (S)- Hydroprene (CAS #65733-18-8) . . . . . . . . 9% How Gentrol IGR Concentrate Works Gentrol IGR (Insect Growth Regulator) Concentrate travels deep For use in Food and non-food areas Roaches, drain and fruit flies, Bedbugs, and stored product pest populations.