CHAPTER 20 PESTICIDES & PEST CONTROL

1. CHAPTER 20PESTICIDES & PEST CONTROL

2. WHAT IS A PEST • Any species that does the following: -Competes with humans for food -Invades lawns and gardens -Interferes with human activity -Spreads disease -Nuisance

3. I. TYPES OF PESTICIDES • Insecticides • Herbicides • Fungicides • Nematocides (Round worms) • Rodenticides

4. A. 1st Generation Pesticides -Generally described as those first used and that were derived from natural sources. Sulfur: Used pre-500B.C. Toxic Chemicals: (1400’s) Arsenic- does not break down, Lead and Mercury -This approach was abandoned as late as the1920’s -Still find measurable levels in tobacco and other crops grown on that soil

5. 1st Generation - continued Natural Pesticides: (1600’s) Nicotine Sulfate – from tobacco plants (1800’s) Pyrethrum, Rotenone- from Chrysanthemum flower and tropical legumes

6. B. 2nd Generation Pesticides -Generally described as those that are chemically produced -DDT (Dichlorodiphenyl-trichloroethane) *Discovered by Paul Muller (won the Nobel Prize) *1st used in 1939 *Use in the U.S. stopped in 1972 as a result of adverse effects on the environment and population decreases in unintentional species. - It is still sold to foreign countries

7. Biological Magnification

8. OUTCOMES OF DDT

9. C. Pesticide Use Today 1. TODAY(since 1850) -50 fold increase in the use of pesticides since the 1950’s -10x stronger than the original pesticides -2.5 million tons used per year, worldwide.

10. 2. IN THE USA -Around 25,000 pesticide products -25% used for homes, parks, pools, golf courses -The average lawn receives 10x more synthetic pesticide than US cropland -250,000 people become ill each year

11. D. Broad vs. Narrow 1. Broad Spectrum Agents: -Toxic to many species 2. Selective / Narrow Spectrum: -Specific to a certain species -Pesticides vary in their PERSISTANCE (how long they remain in the environment)

12. II. THE CASE FOR PESTICIDES • Those that support the use of pesticides state that the benefits outweigh the potential harmful effects for many reasons.…. • A. Save human lives: • Protection against diseases like malaria, typhus and sleeping sickness

13. B. Increase food supply: • 55% of food is already lost to pests • $65 million / yr • Helps lower food costs

17. C. Increased Profit to farmers: • Every $1 spent on pesticides increases farm profit by $4

18. D. They work faster and better than alternatives: • -Control most pests at reasonable cost • -Have a long shelf life • -Easily shipped and applied • -Relatively safe when handle correctly

19. E. Relatively Safe: • Health risks are insignificant when used properly • Today’s pesticides are actually safer than those of the past. • Many of the new pesticides are used at a lower rate than in the past.

20. III.THE CASE AGAINST PESTICIDES • Those that oppose the use of pesticides state that they are harmful for many reasons.…. A. Can cause Genetic Resistance: • Reproduce rapidly and can develop a resistance in 5-10 years • Surviving organisms come back stronger. • Leads to Pesticide Treadmill- using stronger doses, switching to new chemicals, and an increase in frequency of use

21. 600 500 400 Number of species 300 200 100 0 1950 1960 1970 1980 1990 2000 2010 Year RISE OF GENETIC RESISTANCE TO PESTICIDES 1945-98 Gypsy moth cateripllar Boll weevil Insects and mites Plant diseases Weeds Fig. 20.4, p. 507

22. B. Broad Spectrum insecticides kill natural predators & parasites • 1/3 of the most destructive pests are secondary pests that became widespread after the use of insecticides

23. C. Pesticides Do Not Stay Put • Less than 2% of the pesticides used actually reach the target pests • Less than 5% of herbicide reaches the appropriate weeds • Pesticides may end up in the air, water, bottom sediments, food or non-target organisms.

24. D. Some Pesticides Harm Wildlife • Destruction of more than 20% of honeybee colonies • Costing farmers $200 million in lost pollination • Kills 67 million birds • Kills 6-14 million fish • Hurt 20% endangered species

25. E. Threat to Human Health • 3 million agricultural workers are harmed each yr (300,000 in USA) • Most not reported due to the majority of farm workers being illegal immigrants • 18,000 deaths (probably underestimated) • 165 of the approved active ingredients are carcinogenic • Exposure in food is related to 4-20,000 cases of cancer / year • Birth defects, genetic mutations, nervous system disorders, immune system problems

26. Bhopal India Bhopal, India, 2-3 Dec. 1984On the night of 2-3 December 1984, a sudden release of about 30 tons of methyl isocyanate (MIC) occurred at the Union Carbide pesticide plant at Bhopal, India. The accident was a result of poor safety management practices, poor early warning systems, and the lack of community preparedness. The accident led to the death of over 2,800 people living in the vicinity and caused respiratory damage and eye damage to over 20,000 others. At least 200,000 people fled Bhopal during the week after the accident. Estimates of the damage vary widely between US $350 million to as high as US $3 billion. http://www.bhopal.org/testimony/index.html

28. IV. PESTICIDE REGULATIONS IN THE U.S. A. USE IN THE U.S. (518) • All commercial pesticides require EPA approval for general and/or restricted use. (Based on FIFRA) -Evaluated for biologically active ingredients + affects -If approved the EPA sets acceptable tolerance levels

29. Between 1972-2000, EPA banned or restricted 56 active pesticide ingredients in U.S. – may be used elsewhere. • EPA asked to reevaluated 600 pre-1972 active ingredients used in pesticides. (by 2000 less than 10% completed) • -weak enforcement • -weak laws for pre 1972 toxins

30. B. OTHER DISTURBING FACTS • 165 active ingredients in U.S. approved pesticides are known to be carcinogens • Missouri study showed increased childhood brain cancer with use of various pesticides. • Also, associated with immune and endocrine disorders • Swedish report showed, exposure to glyphosatetripled chances of getting non-Hodgkin’s lymphoma.

31. C. HOW TO IMPROVE PESTICIDE REGULATIONS (519) • Need to make human health the primary consideration for setting pesticide limits. • New tests for evaluating toxicity of pesticides • Consider the cumulative exposures of all Pesticides

32. D. HOW TO IMPROVE PESTICIDES • Kill only target species would be ideal • Harm no other species • Break down into something harmless after doing its job • Not cause genetic resistance in target organisms • Be more cost effective than doing nothing

33. The War Against Insects

34. V. OTHER WAYS TO CONTROL PESTS A. Goals of Pesticide Control • One of the biggest problems with the use of pesticides is in determining the ECONOMIC THRESHOLD. • This is point where cost of damage due to not applying pesticides outweighs the cost of application of pesticides. • To protect themselves, farmers often practice • INSURANCE SPRAYING • COSMETIC SPRAYING- Making its appearance more desirable

35. B. Alternatives to Pesticides 1.Cultivation Practices; • crop rotation • changing planting times • planting trap crops • increasing habitat for natural predators 2. Create Genetically Resistant Plants;

36. A Fungus Among Us

37. Con’s -no mass reproduction -slow -must be protected from spraying -can multiply faster than pest -requires a lot of research & development Pro’s -focus on target -are nontoxic -save money -minimize resistance 3. Biological Pest Control;

40. 4. Insect Birth Control; • Sterilization of insects, used with screwworms, fruit flies • Involves irradiating males • Disadvantages include… -high cost -estimating mating times/behaviors • -need large # of males • -males must be reintroduced

41. 5. Sex Attractants; The use of pheromone baited traps. Pheromone- is a species-specific chemical sex attractant. 6. Hormones to stunt growth;

42. 7. Spraying with hot water; 8. Exposing food to gamma radiation

44. C. INTEGRATED PEST MANAGEMENT • Approach where crops and pests are examined as part of an ecological system. • Overall aim is to reduce crop damage and economic losses but not complete eradication of the pest. • Requires more expert knowledge and multiple approaches to pest controlSlower acting than pesticides • Only small amounts of pesticide are used at critical times

45. IPM is ? • A chemical program • A ecological program • A biological program

46. Ways to Reduce Threat to Pesticides in the Food We Eat. • Scrub all food in soapy water • Grow own fruits and vegetables using organic gardening methods • Purchase organically grown foods

47. Did you know? • Flea collars are linked to brain tumors • Pre-1972 pesticides may still have untested chemicals as ingredients • Round-Up is linked to Non-Hodgkins type Lymphoma

48. THE END