Chapter Summary

Biological pests are organisms that reduce the availability, quality, or value of resources useful to humans. Pesticides are chemicals intended to kill or drive away pests. Many nonchemical pest-control approaches perform these same functions more safely and cheaply than do toxic chemicals. Of the millions of species in the world, only about 100 kinds of animals, plants, fungi, and microbes cause most crop damage. Many beneficial organisms are injured by indiscriminate pesticide use, including natural predators that serve a valuable function in keeping potential pests under control.

Humans have probably always known of ways to protect themselves from annoying creatures, but our war against pests entered a new phase with the invention of synthetic organic chemicals such as DDT. These chemicals have brought several important benefits, including increased crop production and control of disease-causing organisms. Indiscriminate and profligate pesticide use also has caused many problems, such as killing nontarget species, creating new pests of organisms that were previously not a problem, and causing widespread pesticide resistance among pest species. Often highly persistent and mobile in the environment, many pesticides move through air, water, and soil and bioaccumulate or bioconcentrate in food chains causing serious ecological and human health problems.

A number of good alternatives offer ways to reduce our dependence on dangerous chemical pesticides. Among these are behavioral changes such as crop rotation, cover crops, mechanical cultivation, and planting mixed poly-cultures rather than vast monoculture fields. Consumers may have to learn to accept less than perfect fruits and vegetables. Biological controls such as insect predators, pathogens, or natural poisons specific for a particular pest can help reduce chemical use. Genetic breeding and biotechnology can produce pest-resistant crop and livestock strains, as well. Integrated pest management (IPM) combines all of these alternative methods together with judicious use of synthetic pesticides under precisely controlled conditions.

Regulating pesticide use is a controversial subject. Many people fear that we are exposed to far too many dangerous chemicals. Industry claims that it could not do business without these materials. The Delaney Clause, an amendment to the Federal Food, Drug, and Cosmetic Act, prohibits willful addition of any known carcinogen to foods, drugs, or cosmetics. Although noble in intention, this amendment has become difficult to enforce as we find that many commonly used materials are carcinogens. Should we weaken the law and allow some carcinogens as long as the risk is “negligible”?

Many of the procedures and approaches suggested for agriculture and industry also work at home to protect us from pests and toxic chemicals alike. By using a little common sense, we can have a healthier diet, lifestyle, and environment.