Insect Growth Regulators (IGR) Generally have very little toxicity to mammals since it disrupts the growth and development processes specific to insects. Can cause sterilization of adult insects. They contain a synthetic juvenile hormone "look-alike" which disrupts the normal growth development of cockroaches, stored product pests, fleas, and others. When they become adults, they will become adults incapable of reproducing. It also disrupts the normal life cycle thus killing these insects. Below are products containing IGR material. The two products that we carry that contain IGRs are, FLEA PRODUCTS Carpet Spray and Nylar IGR