Pesticide and Silent Spring

Reading Guide to Carson, Silent Spring

Reading Guide to Rachel Carson, Silent spring / Drawings by Lois and Louis
Darling. Boston: Houghton Mifflin, 1962. (QH545.P4 C38 1962)
Read: Chapter 6 (Earth’s Green Mantle)
Core Question/Issue:
What impacts does manipulation of life bring? The use of herbicide and the ignorance of man.
What are the impacts on the manipulation of life?
Introduction:
 The author: Rachel Carson
 The book: an overview
 The chapter
# Example from text to illustrate harm of herbicides
# The functions of “weeds”
# Non-selective herbicides
 Controversy and reflections
# Opposition
# Questions to think about

Rachel Louise Carson (1907 – 1964) was an American marine biologist and a writer. While she was the author of several bestsellers on natural history, her most well-known and influential work was Silent Spring, a book which concerns the irresponsible application of synthetic pesticides and its consequences. The book successfully raised public awareness to the detrimental effects of pesticides. It has even caught the attention of President Kennedy, who ordered an investigation into
Carson’s claims and eventually led to the banning of DDT (a pesticide commonly used in the 1940s and 1950s to curb the spread of malaria) in the US.1
Carson began the book by conjuring a desolate spring scene, a “silent spring” as suggested in the title, devoid of bird songs or any other sounds of life. As revealed gradually in later chapters, this disturbing image is the result of the indiscriminate use of pesticides, which has brought devastation to the environment and wildlife. In fact, more than half of the book is devoted to various cases of the misuse of pesticides to illustrate how these chemicals can cause ecological disasters and health issues. Many of the chemicals mentioned were insecticides, especially DDT and several other chemicals commonly used at that time. Citing numerous examples of harmful consequences of pesticide misuse, Carson calls for carefully-managed use of
1

"Silent Spring”, Wikipedia, (21:53, 11 February 2010).

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Reading Guide to Carson, Silent Spring

pesticides with more consideration for the natural balance of the ecosystem.
The selected reading, Chapter 6 of Silent Spring, is the only chapter with its discussion focused on herbicides. At the beginning of the selected chapter, the author pointed out that plants play a major role in supporting life on Earth. At the bottom of the food chain, plants are vital in capturing energy from the sun and converting it to forms which can be utilized by other animals. Life can thrive in a wide range of landscapes, from mountains to plains, deserts to wetlands, supported by various types of plants suited to the particular conditions there. A “web of life” is formed through the course of evolution, as the author illustrated using the example of the sage land in
Western United States. Adapted to the cold and dry climate, the evergreen sage was the principal food source for many animals during the long winters on the high plains.
The plant, aside from providing energy, also holds moisture for the growth of grass and functions as shelter for the birds. However, the government then failed to recognize the importance of the sage and regarded it as “weeds” to be eliminated to give way to more grazing land for the cattlemen. The result of the spraying was the killing of not only the sage but also other plants nearby. Wildlife that has once depended on these plants dwindled, and the cattle-grazing also suffered as the grass couldn’t grow well without the moisture-holding sage.
The above was merely one of many examples where man destroyed the balance of the ecosystem out of ignorance and ultimately brought harm to himself. The author stressed that many of the “weeds” are actually useful plants in which their functions man frequently overlook. The hedgerows, for instance, are home to many animals as well as food for insects. While we do not depend directly on these plants, our agriculture depends on pollinating insects which in turn live on the. Reckless actions to eliminate the plants would ruin these relations and eventually backfire on man.
On the other hand, Carson urged readers to think twice before using herbicides.
Due to their non-specific nature, herbicides indiscriminately kill off the targeted
“weed” and other plants, sometimes even affecting the livestock and men. An alternative the author suggested is biological control. With the introduction of natural enemies which selectively target the “weed” in question, unwanted vegetation could be kept under control while other plants and animals remain unaffected.
Carson’s book has been widely recognized since it came out in 1962. It was selected by the book-of-the-Month Club, and in 2006 it was listed as one of the 25 greatest science books of all time by Discover Magazine. While the book has won
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Reading Guide to Carson, Silent Spring

support from many, not all are convinced. Opponents argued that Silent Spring inspired the ban on DDT and thus resulted in the increased toll of malaria in poor countries. Criticisms were also directed at claims in the book that DDT caused cancers in humans. Critics maintained that scientific researches on health implications of DDT had been inconclusive, and they believed that many examples of health issues listed in the book were not necessarily related to pesticides exposure. As readers without professional knowledge in the specific field, we could find it difficult to decide if the claims are valid.2 When both sides based their claims on scientific researches, how would you make your choice? If we take the vested interests of pesticides manufacturers and chemical researchers into consideration, would it change your decision?
Controversies aside, this book has prompted us to ask important questions about humans and our relationship with nature. How much do we know about it? Could we control it? How do we make use of it while ensuring that future generations can still enjoy the same abundant resources? What should our role be in nature?
Suggested Outline of the text
1-2: Introduction: humans’ ignorance and arrogance.
3-15: Example of sage eradication program by spraying herbicide
3-9: Mutual dependence relationship between the sagebrush and other life forms as a result of evolution.
10-11: The eradication of sage
12-15: Effects of sage eradication by spraying
16: Current situation of herbicide usage
17: The true costs of spraying
18-21: Loss of beautiful scenery and tourist goodwill upon spraying
22: Abuse of spraying causes unnecessary damage to plants and animals
23: The unintended killing of other plants
24: Unnecessary spraying of roadside plants
25-27: The attitudes of herbicide sellers and federal field men towards spraying
28-30: The role of natural vegetation in nature
31-32: Shortcomings of herbicides
2

Carson’s conjecture is controversial. There are opinions from both sides. In his article “Silent Spring at 40: Rachel Carson's classic is not aging well”
(http://reason.com/archives/2002/06/12/silent-spring-at-40), Ronald Bailey strongly criticizes Carson’s conjecture. Keith Lockitch holds a similar position in “Rachel Carson's Genocide”
(http://capmag.com/article.asp?ID=4965) while Kirsten Weir shows a more balanced point of view in
“Rachel Carson's birthday bashing” (http://www.salon.com/news/feature/2007/06/29/rachel_carson/).
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Reading Guide to Carson, Silent Spring

33-37: Alternative method – selective spraying
33: Not all plants are problematic
34: Introduction to selective spraying and its objective
35-37: The advantages of selective spraying
38-42: The adverse effects of common herbicides in particular 2,4-D and its related compounds. 43-46: The functions of weeds
47-48: Chemical control may be ineffective
49-59: Alternative method – biological control
49-50: The example of Crabgrass
53-57: The example of the Klamath weed
58-59: The example of prickly pears (cactus)
60: Conclusion
Study Questions:
True or False:
(Para. 1-5)
1. The author thinks that humans should not interfere with any of the relations between life and the earth.
(Para. 3-10: Interdependence between the sagebrush and other life forms as a result of evolution)
2. What is special about the leaves of sage so that it can survive the long ages of natural selection in the dry West?
(a) The roots absorb nutrients effectively.
(b) Good sunlight in the dry West.
(c) The small grey leaves can hold moisture.
(d) The grouse provides food for them.
(Para. 3-10: Interdependence between the sagebrush and other life forms as a result of evolution)
3. What animals depend on the sage?
I. The grouse
II. The antelope
III. The mule deer
(a) I only.
(b) III only.

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(c) II and III only.

(d) I, II, and III.

Reading Guide to Carson, Silent Spring

(Para. 3-10: Interdependence between the sagebrush and other life forms as a result of evolution)
4. Why did the land management agencies decide to eliminate the sage?
(a) Provide more farming fields.
(b) Satisfy the demands of grazing land.
(c) Protect the antelope from the harsh climate.
(d) Establish a stable balance of natural system.
(Para. 12-15: Effects of eradication by spraying)
5. What is the immediate side effect of spraying on sagebrush as illustrated in the example of the Bridger National Forest?
(a) The lake drained away.
(b) The beavers disappeared.
(c) The waterfowl disappeared.
(d) The willow was killed.
(Para. 12-15: Effects of eradication by spraying)
6. What are the subsequent side effects of spraying on sagebrush as illustrated in the example of the Bridger National Forest?
I. The beavers disappeared.
II. The waterfowl disappeared.
III. The lake drained away.
(a) I only.
(b) III only.

(c) II and III only.

(d) I, II, and III.

(Para. 18-24: The price of spraying)
7. Which commodity is harmed by the use of sprays?
(a) The goodwill of tourists.
(b) More money will be spent on advertisement.
(c) Decrease vegetation yields.
(d) Sprays manufacturers earned less money.
(Para. 28-30: The role of natural vegetation in nature)
8. Which of the followings is/are the function(s) of roadside vegetation?
I. Food for birds.
II. Food for pollinating insects.
III. Nesting areas for birds.
IV. Promoting tourists.
(a) III only.
(b) IV only.

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(c) I, and II only.

(d) I, II, and III only.

Reading Guide to Carson, Silent Spring

(Para. 33-37: Selective spraying)
9. Based on what principle does selective spraying achieve long-term control of tree growth? (a) Grasses are highly resistant to invasion by trees.
(b) Select a better herbicide.
(c) Shrubs are highly resistant to invasion by trees.
(d) Herbicide harms the tree only.
(Para. 33-37: Selective spraying)
10. Which of the followings are the advantages of selective spraying?
I. Beauty of the natural vegetation has not been sacrificed.
II. Long-term control.
III. Lowers potential harm to wildlife.
(a) II and III only. (b) I and III only.

(c) I and II only.

(d) I, II, and III

(Para. 38-42: The adverse effects of common herbicides)
11. Why are plants sprayed with 2,4-D (a herbicide) dangerous for cattle?
(a) Cause them suffering from genetic diseases.
(b) Cause them lake of oxygen.
(c) Spraying causes no vegetation.
(d) Livestock losses.
First statement

Second statement

True
True
True
False

True
True
False
True

(a)
(b)
(c)
(d)

2nd statement is a correct explanation of 1st statement.
2nd statement is NOT a correct explanation of 1st statement.

(Para. 43-46: The functions of weeds)
12. Roses grow better with marigolds than

An excretion released by marigolds kills nematodes in the soil.

growing alone.
(Para. 43-46: The functions of weeds)
13. What is/are the functions of those plants people consider as weeds?
I. Existence of weeds provides mutual benefit with soil.
II. Serve as an indicator of the condition of soil.
III. As a matter of scientific importance.
(a) I, and III only.
(b) I, and II only.
(c) II, and III only.
(d) I, II, and III.
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Reading Guide to Carson, Silent Spring

True or False
(Para 47)
14. Grasses themselves have become “weeds” because there are less plants to compete with them after the spraying of 2, 4-D.
(Para. 48-49: Unsuccessful examples on blanket spraying)
15. Which of the following reason(s) caused more ragweed after blanket spraying?
I. The chemical itself enhances the growth of ragweed.
II. The chemical increased the pollen content in atmosphere.
III. The chemical kills the protective vegetation and creates open areas on the field.
(a) I only.
(b) III only.
(c) I and II only. (d) II and III only.
(Para. 53-57: biological control - Klamath weed)
16. As mentioned in the text, where did Klamath weed cause problems?
I. California
II. Europe
III. Australia
(a) I only.

(b) II only.

(c) I and II only.

Answer:

Enter to get the answers to the study questions.

http://www.cuhk.edu.hk/oge/gef/studyqs/nature/

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(d) II and III only.