Are there ways to control gypsy moths, cabbage loopers, and other agricultural annoyances without using chemical pesticides? The answer is yes. There are now available a number of biological products registered with the Environmental Protection Agency (EPA) that can be used to control a fairly wide array of insects, weeds, and other plant pests (Figure 3.1). Most of these products are based on microorganisms (''bugs") that are the pest's natural enemies—disease-causing "pathogens" that kill the pest outright or foul-smelling, worse-tasting "antagonists" that drive the pest away.

These biopesticides have several advantages over chemical pesticides. Biopesticides act through mechanisms specific to the target organism and nonexistent in other organisms, thus sabotaging the target's metabolism without poisoning every other creature as well. Biopesticides are fully biodegradable, leaving no residues behind, and biopesticides can be applied with the same equipment used to apply conventional pesticides, at the same intervals, and with essentially equivalent results.

If these marvelous products are truly available, why isn't there a greater awareness of them? There are several reasons. Although some of these products have been around for 20 years or more, they did not work as well in the past as they do now, thanks to continuing research. Nor have they ever been price competitive with conventional pesticides. Where they have been used extensively, for example, in eastern U.S. oak forests to control gypsy moths, they have been well received. They have, however, generally been seen as specialty products for "niche" markets, rather than as alternatives to chemical pesticides in the broadest sense.

This view may be changing. Opposition to chemical pesticides continues to increase with increasing awareness of their environmental consequences. The cost of developing new chemical pesticides and of registering them with the EPA—a precondition to their sale in the United States that requires extensive environmental and toxicological studies—has led to a decline in the rate of new product development. Furthermore, many insects and plant diseases have shown an amazing ability to develop resistance to an ever-broadening array of pesticides, limiting the useful life of even newly developed products. Biopesticides, on the other hand, have received increasing attention over the past five years. Several new biotechnology companies are focusing specifically on biopesticide development, and even old-line agricultural chemical companies have begun to shift their pesticide lines toward environmentally compatible products.

Biotechnology—biocatalysis—is indispensable to biopesticide development, as the story of the development of insecticides from the soil