Parasites and predators can be purchased from a wide array of companies throughout the United States and Canada. Frequently, addresses are listed in various trade magazines and other gardening resource reading material. Also, the California Department of Food and Agriculture has assembled a listing of commercial businesses that sell beneficial organisms, such as insects, mites, and nematodes, that can be used for pest control, either as an alternative to chemical control or in an integrated program with chemicals. The title of this publication is Beneficial Organisms of North America. For additional information on the availability of this publication, contact California Environmental Protection Agency, Department of Pesticide Regulation, Pest Management and Licensing, 1001 I Street, P.O. Box 4015, Sacramento, CA 95812-4015, phone: 916-445-4300.