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

2. Why worry about 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 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. What is a pesticide? toxic chemical used to control pest populations

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

5. First Generation Pesticides used prior to 1940s Two Groups: Inorganics + Botanicals Sulfur, lead, arsenic, mercury, persistant, accumulate Plant extracts: nicotine (tobacco), pyrethrum (chrysanthemum), rotenone (tropical legumes), are degradable used prior to 1940s Two Groups: Inorganics + Botanicals Sulfur, lead, arsenic, mercury, persistant, accumulate Plant extracts: nicotine (tobacco), pyrethrum (chrysanthemum), rotenone (tropical legumes), are degradable

6. Bug Bashers Got Bored

7. Second Generation Pesticides Primarily synthetic organic compounds used since WWII, synthetic poisons used today Over 600 biologically-active compounds Broad-spectrum agents Toxic to many Narrow-spectrum agents Toxic to specific group Target species/Nontarget species Primarily synthetic organic compounds used since WWII, synthetic poisons used today 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

8. Narrow v. Broad Spectrum Kills only organism intended & does not harm others Kills various organisms (pest + others)

9. Major Categories INSECTICIDES categorized based on chemical structure of compound Chlorinated Hydrocarbons  organic compound containing chlorine - broad spectrum - banned or restricted - slow to degrade- terribly persistant Organophosphates  organic compound containing phosphate -VERY poisonous - persistant Carbamates  contain carbamic acid (CH 3 NO 2 ) - Broad spectrum

10. Major Categories HERBICIDES categorized based on how they act and what they target Selective v. Nonselective - kills only certain kinds - kills all vegetation  Broad Leaf v. Grass

11. Examples 2,4-D & 2,4,5-T both broad leaf, both disrupt natural growing process via hormone disruption, contain dioxins 2,4,5-T banned by EPA due to human health risk Agent Orange = 2,4-D + 2,4,5-T (used in Vietnam War)Agent Orange Generations of Agent Orange

12. 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  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

13. The Case for Pesticides 1. Disease Control Fleas/Lice carry typhus Mosquitos carry malaria DDT still used in developing countries to prevent malaria but banned in most developed countries. 2. Crop Protection

14. 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  Kill only target pests  Do not harm other species  Break down quickly  Do not cause genetic resistance  Are more cost-effective than doing nothing

15. DDT DDT (dichlorodiphenyltrichloroethane) DDT's insecticidal properties were not discovered until 1939, and it was used with great success in the second half of World War II to control malaria and typhus among civilians and troops.

16. DDT Use in the US Spraying on Kids So Safe You Can Eat It! Harmless to Humans

17. Individuals Matter: Rachel Carson 1962, Silent Spring introduced the dangers of pesticides (DDT and others) to the environment. 1972, DDT banned in the USA 2004 Stockholm Convention banned abroad

18. The Case Against Pesticides  Genetic Resistance, SuperPests  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  Genetic Resistance, SuperPests  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

19. The Case Against Pesticides PERSISTENCE = ability to degrade/break down naturally in environment BIOACCUMULATION = storage of pesticides (that do not break down) usually in fatty tissues of organisms LEADS TO: organisms higher on food chain having  conc. of bioaccumulated pesticides stored in body FIG 22.9 BIOMAGNIFICATION =  in pesticide concentration as you move up the food web

20. Superpests: Genetic Resistance Superpests are resistant to pesticides. Superpests like the silver whitefly (left) challenge farmers as they cause > $200 million per year in U.S. crop losses.

21. Alternatives to Pesticides 1. Cultivation Methods - interplanting- strip cutting 2.Biological Controls - use of natural predators, parasites, organisms to control pests 3. Phermones & Hormones - synthetic versions used to interrupt natural cycles

22. Controlling Pests  Adjusting cultivation practices  Use genetically-resistant plants  Biological pest control  Adjusting cultivation practices  Use genetically-resistant plants  Biological pest control

23. Control Pests Biological pest control: Wasp parasitizing a gypsy moth caterpillar.

24. Alternatives to Pesticides 4. Reproductive Controls -sterilizing male members reduces potential population 5. Genetic Controls - pest resistant plants 6. Quarantine -restrict importation of exotics that could harbor pests

25. 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.

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

27. Alternatives to Pesticides 7. IPM – Integrated Pest Management -variety of controls at once -management of pests not eradication - Ag. industry must be educated on options and effective strategies for success

28. 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  Ecological system approach  Reduce pest populations to economic threshold  Field monitoring of pest populations  Use of biological agents  Chemical pesticides are last resort

29. Effects of IPM Fig. 20-6 p. 520

30. Pesticide Legislation Government regulation has banned a number of harmful pesticides but some scientists call for strengthening pesticide laws. –The Environmental Protection Agency (EPA), the Department of Agriculture (USDA), and the Food and Drug Administration (FDA) regulate the sales of pesticides under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). –The EPA has only evaluated the health effects of 10% of the active ingredients of all pesticides.

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

32. Pesticide Regulation  Food Quality Protection Act (FQPA) - Established in 1996 - New standards for pesticide tolerance based on no harm to human health  Food Quality Protection Act (FQPA) - Established in 1996 - New standards for pesticide tolerance based on no harm to human health