Several pressures have accelerated the search for more environmentally and toxicologically safe and efficacious pesticides. Most commercially successful pesticides have been discovered by screening compounds synthesized in the laboratory for pesticidal properties. The increasing incidence of pesticide resistance is also fueling the need for new pesticides. Furthermore, most synthetic chemicals pesticides are halogenated hydrocarbons with relatively long environmental half-lives and more suspect toxicological properties than most natural compounds. Thus, natural compounds have increasingly...