1. 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

2. Pest Control Purposes Protect our food Protect our health Convenience In 1999 the U.S. used 912 million pounds of herbicides and pesticides and cost $11.1 billion dollars

3. Pesticide Use in the United States

4. Types of Pesticides Insecticides Rodenticides Fungicides Herbicides

5. Philosophies of Pest Control Chemical treatment  Use of chemicals to kill large numbers of the pest  Short-term protection  Environmental and health consequences

6. Philosophies of Pest Control Ecological control  Control based on pest life cycle and ecology  Long-lasting  Control agent may be an organism or chemical  Controls a specific pest  Emphasizes protection rather than eradication

7. Philosophies of Pest Control Integrated Pest Management (IPM)  Combines chemical treatment and ecological control  Uses all suitable methods in a way that brings about long-term management of pest populations with minimal environmental impact

8. Development of Chemical Pesticides First-generation pesticides (inorganic)  First attempt at chemical technology  Toxic heavy metals (lead, arsenic, mercury)  Toxic to humans and agricultural plants Accumulate in soil Inhibit plant growth Poison animals and humans  Pests developed resistance

9. Development of Chemical Pesticides Second-generation pesticides  1930’s  Pest populations increased and 1 st generation pesticides began failing  Synthetic organic chemicals  Toxic to humans and agricultural plants  Still…pests developed resistance

10. The DDT Story DDT: the magic bullet  Extremely toxic to insects; seemed nontoxic to humans and other mammals  Cheap  Broad-spectrum and persistent  Effective for disease prevention (typhus fever, malaria)  Expanded agricultural production  Paul Müller awarded Nobel prize in 1948

11. Problems Stemming from Chemical Pesticide Use Development of resistance by pests Resurgences and secondary pest outbreaks Adverse environmental and human health effects

12. Resistance Chemical pesticides lose effectiveness  Solution Use larger quantities Use more potent pesticides Resistant pest populations produce next generations  Pesticides destroy sensitive individuals leaving resistant insects  quick reproduction  natural selection

13. Pesticide Resistance

14. 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. These occur because the chemical approach fails because it ignores basic ecological principles. It assumes that the ecosystem is a static entity in which one species can simply be eliminated with no effect on the food web.

15. The Pesticide Treadmill

16. Human Health Effects 2001 – 90,000 people suffered acute poisoning from pesticides (most were farm workers or employees of pesticide companies) Cancer (lymphoma and breast cancer) Dermatitis Neurological disorders Birth defects Sterility (male) Endocrine system disruption Immune system depression

17. 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.

18. Aerial Spraying

19. Environmental Effects 1950’s and 1960’s - DDT led to the decline in populations of several bird species  Bald eagle  Peregrine falcon Eggs were breaking in the nest before hatching Birds were getting high levels of DDT via bioaccumulation & biomagnification Silent Spring – Rachel Carson – bird sanctuary sprayed for mosquito control; start of environmental movement Half life of DDT = 20 years

20. Environmental Effects Bioaccumulation – small, seemingly harmless amounts of chemicals received over a long period of time may reach toxic levels  Enter into lipids of the body and held there  Body can’t metabolize them Biomagnification – bioaccumulation is compounded in the food chain; accumulates a concentration of contaminant in its body that is many times higher than that in its food

21. Biomagnification

22. Nonpersistent Pesticides Substitutes for banned pesticides Break down after a few weeks Can still be harmful because of:  Toxicity (inhibit nervous system)  Dosage (need frequent application)  Location

23. Alternative Pest Control Methods (IPM) Ecological control involves working with natural factors instead of synthetic chemicals; techniques are called natural control or biological control 4 types  Cultural control  Control by natural enemies  Genetic control  Natural chemical control

24. Cultural Control Nonchemical alteration of one of more environmental factors that the pest finds the environment unsuitable Disposing of sewage Avoiding unsafe water Proper hygiene Changing linens Disposing of garbage Cleaning house Sanitation requirements in handling and preparing foods Refrigeration and drying of food

25. Control Using Natural Enemies Problem – finding organisms that provide control of the target species without attacking other, desirable species Impost alien species as a last resort

26. Genetic Control Plants or animals are bred to be resistant to the attack of pests.  Chemical barriers  Physical barriers Example – potato blight (fungus) in Ireland (1845- 1847); million people starved and a million people emigrated

27. Natural Chemical Control A volatile chemical produced by the opposite sex of a species which alters the reproductive behavior of the opposite sex.  Perfumes Manipulation of pests’ hormones or pheromones to disrupt the life cycle Japanese beetle trap

29. Pesticides and Policy Federal Insecticide, Fungicide, and Rodenticide Act  1947; 1972; requires manufacturers to register pesticides with the EPA before marketing them 1996: Food Quality Protection Act  Safety standard – a reasonable certainty of no harm for substances applied to food