1. Chapter 20 Pesticides and Pest Control
G. Tyler Miller’s
Living in the Environment
13th Edition

2. Pests Compete with humans for food Invade lawns and gardens
Destroy wood in houses
Spread disease
Are a nuisance
May be controlled by natural enemies

3. Pesticides: Types Chemicals that kill undesirable organisms
Insecticides (insects)
Herbicides (weeds)
Fungicides (fungus)
Rodenticides (rats and mice)
See Table 20-1 p. 514

4. First Generation Pesticides
Primarily natural substances
Sulfur, lead, arsenic, mercury
Plant extracts: nicotine (tobacco), pyrethrum (chrysanthemum), rotenone (tropical legumes)
Plant extracts are degradable

5. Second Generation Pesticides
Primarily synthetic organic compounds
Over 600 biologically-active compounds
Broad-spectrum agents
Toxic to many
Narrow-spectrum agents
Toxic to specific group
Target species/Nontarget species
See Table 20-1 p. 514

6. The Case for Pesticides
Save human lives
Increase supplies and lower cost of food
Work better and faster than alternatives
Health risks may be insignificant compared to benefits
Newer pesticides are becoming safer
New pesticides are used at lower rates

7. Characteristics of an Ideal Pesticide
Kill only target pests
Do not harm other species
Break down quickly
Do not cause genetic resistance
Are more cost-effective than doing nothing

8. Individuals Matter: Rachel Carson
Wrote Silent Spring which introduced the U.S. to the dangers of the pesticide DDT and related compounds to the environment.

9. The Case Against Pesticides
Genetic resistance
Can kill nontarget and natural control species
Can cause an increase in other pest species
The pesticide treadmill
Once started we must continue, often at higher and higher rates
Pesticides do not stay put
Can harm wildlife
Potential human health threats

10. Pesticide Regulation in the United States
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)
Established 1947/Amended 1972
EPA reviews evaluation of chemicals
Sets tolerance levels
Inadequate and poorly enforced

11. Pesticide Regulation in the United States
Food Quality Protection Act (FQPA)
Established in 1996
New standards for pesticide tolerance based on no harm to human health

12. Other Ways to Control Pests
Economic threshold
The point at which economic losses caused by pest damage outweigh the cost of applying a pesticide.
Adjusting cultivation practices
Use genetically-resistant plants
Biological pest control

13. Other Ways to Control Pests
Biological pest control: Wasp parasitizing a gypsy moth caterpillar.

14. Other Ways to Control Pests
Genetic engineering can be used to develop pest and disease resistant crop strains.
Both tomato plants were exposed to destructive caterpillars. The genetically altered plant (right) shows little damage. Contains a gene from bacteria called the Bt gene.

15. Other Ways to Control Pests
Biopesticides
Insect birth control
Hormones and pheromones
Ionizing radiation

16. Integrated Pest Management
Ecological system approach
Reduce pest populations to economic threshold
Field monitoring of pest populations
Use of biological agents
Chemical pesticides are last resort