The agricultural industry of the 1990s is challenged to find new methods and materials for controlling pests and diseases. New legtslatton, including the 1996 Food Quality Protection Act, Worker Protection Standard, and Pesticide Reregistratton, are limiting the availability of traditional chemical pesticides. Governmental policies committed to the institution of integrated pest management (IPM) programs, the increasing resistance developed by insects and pathogens to chemical pesticides, and the public concern about chemicals in general has initiated a re-evaluation of pesticide use. increasingly, farmers in developed and developing nations are looking toward the use of natural materials as pest-control agents (1). Neem-based insecticides containing azadirachtin address these concerns. The insect-growth regulator (IGR), azadtrachtin, affects over 300 species of Insects, including such important pests as armyworms, leafminers, aphids, whiteflies, psyllids, and numerous other insect pests (2). In addition to controlling these pests, many azadirachtin-based insecttcides have negligible effect on natural beneficial insects, and low environmental impact (3). These properties make azadirachtin a sensible material to use in most pest-management programs. However, significant manufacturing, regulatory, and application problems had to be solved before azadirachtin could be brought to the market. Since then introduction into the agricultural market in the United States in 1993, azadirachtmbased pesticides are fast becoming an important tool in crop protection, although the total amount of azadirachtin sold is much less than 1% of all insecticides sold.