Remembering Rachel Carson

Posted: March 21, 2013

Last year marked the 50th anniversary of the publication of Rachel Carson’s Silent Spring, a work that influenced the creation of the US Environmental Protection Agency and how people everywhere think about pesticides and other chemicals in the environment.[1],[2]

While I have long been aware of Carson and her work, I had not actually ever read Silent Spring, a somewhat shameful confession for an entomologist to make. So, I marked this anniversary by finally reading and reflecting on this influential work. From what I had learned as a college student in the late 1970’s and early 1980’s in classes in which Carson and her works were mentioned (and it was never more than a brief mention, just as often to disparage as to praise), I had no expectation that I would find what I did. In Silent Spring, Carson presents an extremely well-reasoned and convincing argument, beautifully written and logically presented, against the uncritical and widespread (and often ineffective) use of broad-spectrum insecticides, based on an extensive review and analysis of the then current scientific literature and anecdotal evidence of the many impacts of pesticide use (not only the effects of DDT on birds, as many assume).

Especially compelling and concerning are how relevant and current her work remains. Even though we have become more aware of the risks associated with pollutants in the environment since 1962, we now have easily available and apply more pesticides than when Silent Spring was published. One can easily replace the names of the chemicals and issues discussed in Silent Spring for any number of chemicals and technologies used in agricultural production today. As then, the federal government establishes maximum permissible limits of contamination, called “tolerances,[3]” for individual pesticide residues in food. This level is established through animal testing and the tolerance is set for a level below that which causes adverse effects in test animals. However, because diets include multiple types of foods it is likely that exposures are to mixtures of different types of chemical residues, and it is nearly impossible to estimate the total exposure to the mixtures of chemicals and the effects due to their interactions, not to mention the myriad of other types of chemicals that we are constantly exposed to. Therefore, Carson argued it was not valid to assume safety based on exposures to single residues, and called for the end of tolerances. She considered the system of allowing certain levels of pesticide in foods, and the resultant innumerable, recurrent, small-scale exposures more important than contamination from mass spraying. She also called attention to the development of resistance to commonly used insecticides and pest resurgence due to the destruction of natural enemies of insects, problems that continue, and increase today in crops grown using conventional pesticides[4],[5],[6] and in transgenic crops[7].

When Silent Spring was published in 1962, representatives of the agricultural and chemical industry, government officials and scientists reacted by branding Carson as an emotional spinster alarmist, a quack, a Communist, and worse[8]. In addition, lacking a PhD or academic position, she had clearly, in the opinion of her critics, over-stepped her bounds. On the contrary, in Silent Spring, Carson recognized the need to manage insect pests of agricultural and public health significance. She did not argue for an end to pest control, or even to the use of chemicals for pest control. Rather, based on a review and synthesis of scientific literature and media reports, she solicited an end to the uninformed widespread use of broad-spectrum insecticides, mainly organochlorines and organophosphates, and sought the development and adoption of less-toxic chemicals, and more narrowly-focused alternatives based on the best scientific and ecological knowledge. As an alternative to the use of broad-spectrum insecticides, she offers examples of approaches such as the use of less-toxic, more narrow spectrum and less persistent chemicals, and non-chemical methods such as biological control of pests through the use of the natural enemies and pathogens of insects, and where appropriate, sterile insect control techniques. These are approaches that are increasing today, but the dominant approach to pest management remains chemical control. Carson argued that chemicals should not be used without adequate scientific and public knowledge about and consideration of their impact on the environment and human and wildlife health.

She also called for more public education and funding to support research in these areas so that the effective use of alternatives could be expanded.

“If we could divert to constructive research even a small fraction of the money spent each year on the development of ever more toxic sprays, we could find ways to use less dangerous materials and to keep poisons out of our waterways. When will the public become sufficiently aware of the facts to demand such action?”

R. Carson, Silent Spring, Ch. 9, p. 152.

Another compelling thread running through her book is one of democracy and a call for public action.In describing a number of documented and extensive wildlife, livestock, and domestic animal deaths and human health impacts as a result of (often ineffective) government and local insect control programs, she asks who has the power and right to decide, without public consultation, the merit and necessity of such programs.  In the final chapter of Silent Spring[9], she writes,

“The choice after all, is ours to make. If, having endured much, we have at last asserted our “right to know,” and if, knowing, we have concluded that we have been asked to take senseless and frightening risks, then we should no longer accept the counsel of those who tell us that we must fill our world with poisonous chemicals; we should look about and see what other course is open to us.”

Rachel Carson, Silent Spring, Ch. 17: p. 277

Certainly, we are the beneficiaries of a lasting legacy of Rachel Carson. She had a tremendous influence on U.S. national pesticide policy that resulted in a ban on DDT and other pesticides in the U.S. and inspired an environmental movement that led to the creation of the U.S. Environmental Protection Agency. Even though I think we are more environmentally aware today because of Rachel Carson, contamination of the environment with an ever greater array of chemicals has only continued and increased[10],[11],[12], and as Carson pointed out, we are all part of a large experiment. So although Rachel Carson achieved much, we still have much work to do.

Research at Penn State in sustainable and organic agriculture is being conducted by teams of faculty, students, staff, extension educators, farmers and other agricultural professionals. Descriptions of some of this research can be found at Penn State’s Sustainable Agriculture and Organic Agriculture websites.

By Mary Barbercheck, Department of Entomology

[1] Graham, F., Jr. 1978. Rachel Carson. EPA Journal - November/December 1978. Accessed online 22 October 2012.

[2] Lewis, J.  1985.  The Birth of the EPA. EPA Journal – November 1985.  Accessed online 22 October 2012. 

[3] USEPA. Setting Tolerances for Pesticide Residues in Food. Pesticides: Topical & Chemical Factsheets.  Accessed online 22 October 2012. 

[4] Li, X., M. A. Schuler, M. R. Berenbaum. 2007. Molecular Mechanisms of Metabolic Resistance to Synthetic and Natural Xenobiotics.  Annual Review of Entomology 52: 231-253

[5] Dutcher, J.D., 2007.  A review of resurgence and replacement causing pest outbreaks in IPM.  Pp. 27-43, in: General Concepts in Integrated Pest and Disease Management (A. Ciancio & K.J. Mukerjee, eds.), Springer.

[6] Dill, G.M. 2005. Glyphosate resistant crops: history, status and future.  Pest Managemetn Science 61: 219-224

[7] Tabashnik, B.E., A. J. Gassmann, D. W. Crowder, Y. Carrière. 2008. Insect resistance to Bt crops: evidence versus theory.  Nature Biotechnology 26: 199-202

[8] Lear, L.  1997.  Rachel Carson: Witness for Nature. Henry Holt and Co., NY.

[9] Carson, R. 1962.  Silent Spring.  Houghton Mifflin Co., NY

[10] Hogan, C.M. (Lead Author), McGinley, M. (Topic Editor). "Water pollution". In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth July 31, 2010; Last revised Date August 9, 2012; Retrieved October 14, 2012.

[11] Mortensen, D.A., J. F. Egan, B. D. Maxwell, M. R. Ryan, R. G. Smith.  2012.  Navigating a Critical Juncture for Sustainable Weed Management. BioScience 62: 75-84

[12] Fausti, S. W., T. M. McDonald, J. G. Lundgren, J. Li, A. R. Keating, M. Catangui. 2011. Insecticide use and crop selection in regions with high GM adoption rates.  Renewable Agriculture and Food Systems / FirstView Article, pp. 1-10.  DOI:

Contact Information

Mary Barbercheck
  • Professor of Entomology
Phone: 814-863-2982