Insect Growth Regulators (IGRs)

Insect Growth Regulators: These synthetic materials interfere with normal growth and development processes of insects which are regulated by hormones.  In general, insect growth regulators are selective, having significant activity on a relatively small group of insects, and thus play a limited role in the protection of agricultural crops.  The oldest examples are diflubenzuron and altosid.  Diflubenzuron was used extensively in some early boll weevil eradication efforts.  It has significant activity of some species of caterpillar and grasshopper pests and is commercially available as Dimilin®.  Diflubenzuron blocks synthesis of chitin, an important component of insect cuticle. It is also used as a chemosterilant of boll weevil.  Altosid, and the newer insecticide pyriproxyfen (Knack®), are juvenile hormone mimics (i.e., agonists).  Juvenile hormone is a chemical that encourages or regulated the maturing process of insects.  Methoxyfenozide (Intrepid®) and tebufenozide (Confirm®) are ecdysone agonists and are highly active on many species of armyworms and other foliage feeding caterpillars. Ecdysone is the hormone in insects which stimulates molting.