cally exclude agents that are normally considered to be biological control agents and plant varieties that are produced by traditional breeding programs. We will extend the term to agents used in veterinary medicine to control insect and nematode pests.

Pesticides used in companion animals and livestock include pesticides that fit the FIFRA definition and that have been used widely in the treatment of insect infestations of animals. With the advent of the avermectin class of endectocides in the late 1970s—ivermectin, doramectin, milbemycin, and moxidectin—compounds that are active against both external insects and internal parasites became available (figure 1-1). Thus, some pesticides used on animals undergo approval through the FDA New Animal Drug Application (NADA) policy and do not undergo review and approval through FIFRA policy.

From their earliest days agriculturists have been beset by pests. Carvings dating back to 2300 BC in tombs in Egypt, one of the centers of plant domestication, depict locusts eating grain. Biblical passages allude to locusts (Exodus 10:3-6, 12-17, 19) and agricultural pests of other kinds (Joel 1:4, 7, 10-12, 17, 18, 2:19, 25; Deuteronomy 28:38, 39, 42; Amos 4:9,