Environmental Science: Toward a Sustainable Future Richard T' Wright

1
Environmental Science Toward a Sustainable
Future Richard T. Wright
Chapter 16

• Pests and Pest Control
• PPT by Clark E. Adams

2
Pests and Pest Control

• The need for pest control
• Promises and problems of the chemical approach
• Alternative pest control methods
• Socioeconomic issues in pest management
• Pesticides and policy

3
Formosan Subterranean Termite Invades the French
Quarter
4
The Need for Pest Control

• Any organism that has a negative effect on human
  health or economics
• Any organism that is noxious, destructive, or
  troublesome
• Plants or animals (see Fig. 16-2)
• Formosan termite
• Fire ants
• Aedes mosquito
• Medfly

5
Pest Control Purposes

• Protect our food
• Protect our health
• Convenience

6
Pesticide Use in the United States
7
Philosophies of Pest Control

• Chemical technology
• Use of chemicals to kill large numbers of the
  pest
• Short-term protection
• Environmental and health consequences

8
Philosophies of Pest Control

• Ecological pest management
• Control based on pest life cycle and ecology
• Control agent may be an organism or chemical
  (more on next slide)

9
Philosophies of Pest Control

• Specific to pest and/or to manipulate a part of
  the ecosystem
• Emphasizes protection from pest

10
Promises and Problems of the Chemical Approach

• Development of chemical pesticides and their
  successes
• Problems stemming from chemical pesticide use

11
Development of Chemical Pesticides

• First-generation pesticides (inorganic)
• First attempt at chemical technology
• Toxic to humans and agricultural plants
• Pests developed resistance

12
Development of Chemical Pesticides

• Second-generation pesticides
• Used after WW II
• Organic chemical
• Toxic to humans and agricultural plants
• Pests developed resistance

13
The DDT Story

• DDT the magic bullet
• Extremely toxic to insects seemed nontoxic to
  humans and other mammals
• Cheap
• Broad-spectrum and persistent (more next slide)

14
The DDT Story

• DDT the magic bullet
• Effective for disease prevention (typhus fever,
  malaria)
• Expanded agricultural production
• Paul Müller awarded Nobel prize in 1948

15
Aerial Spraying
16
Problems Stemming from Chemical Pesticide Use

• Development of resistance by pests
• Resurgences and secondary pest outbreaks
• Adverse environmental and human health effects

17
Resistance

• Chemical pesticides lose effectiveness
• Resistant pest populations produce next
  generations

18
Genetics of Pest Resistance
19
Genetics of Pest Resistance
20
Pesticide Resistance
21
Resurgence and Secondary Outbreaks

• Resurgences after eliminating a pest, its
  population rebounds in even higher numbers than
  previous levels.
• Secondary outbreaks outbreaks of species
  populations that were not previously at pest
  levels.

22
The Bugs Are Coming!
Time Magazine, July 12, 1976, page 38
23
(No Transcript)
24
The Pesticide Treadmill
25
Human Health Effects

• Cancer, dermatitis, neurological disorder, birth
  defects, sterility, endocrine system disruption,
  immune system depression.
• Agricultural workers suffer acute poisoning
  during pesticide application.

26
Human Health Effects

• Aerial spraying and dumping bring pesticides in
  contact with families and children.
• Soldiers exposed to agent orange in Vietnam
  suffered high rates of cancer and other diseases.

27
Environmental Effects

• DDT led to the decline in populations of several
  bird species
• Bald eagle
• Peregrine falcon
• Bioaccumulation
• Biomagnification

28
Biomagnification
29
Nonpersistent Pesticides

• Substitutes for banned pesticides
• Break down after a few weeks
• Can still be harmful because of
• Toxicity
• Dosage
• Location

30
Alternative Pest Control Methods

• Cultural control
• Control by natural enemies
• Genetic control
• Natural chemical control

31
Complex Life Cycle of Insects
32
Cultural Control
33
Genetic Control

• Plants or animals are bred to be resistant to the
  attack of pests.
• Chemical barriers
• Physical barriers

34
Genetic Control

• Introduction of genes into crops from other
  species transgenic crops.
• Sterile males are released into pest population.

35
Control Using Natural Enemies
36
Natural Chemical Control

• A volatile chemical produced by the opposite sex
  of a species which alters the reproductive
  behavior of the opposite sex.
• Perfumes
• Colognes
• After shave
• Natural body odors

37
Natural Chemical Control

• Manipulation of pests hormones or pheromones to
  disrupt the life cycle
• Japanese beetle trap (see Fig. 16-18)

38
Socioeconomic Issues of Pest Management

• Pressures to use pesticides
• Integrated pest management
• Organically grown food

39
The Economic Threshold
40
Integrated Pest Management (IPM)

• An approach to controlling pest populations using
  all suitable methodschemical and ecologicalin a
  way that brings about long-term management of
  pest populations and also has minimal
  environmental impact

41
(No Transcript)
42
Pesticides and Policy

• Fifra Federal Insecticide, Fungicide, and
  Rodenticide Act
• FQPA of 1996 Food Quality Protection Act
• Pesticides in developing countries

43
FIFRA or FQPA?

• Pesticides evaluated on intended use and
  potential effects to human health and the
  environment
• Training and protection of agricultural workers
• Protection of public from risks of pesticides
  used on food

44
End of Chapter 16