OHP Azatin O Biological Insecticide, 1 QuartAzatin O is a newly formulated biological insect growth regulator (IGR) used to control the larval stage of a broad spectrum of greenhouse and nursery pests. Azatin O is OMRI listed (Organic Materials Resource Institute), is soft on beneficials, and carries a 4 hour REI. Azatin O contains 175 grams of the active ingredient azadirachtin per gallon. Azatin O may be used for insect control on all crops such as ornamentals, vegetables, herbs, and berries,