Environmental Science: Toward a Sustainable Future Richard T. Wright

1. Environmental Science: Toward a Sustainable FutureRichard T. Wright Chapter 16 Pests and Pest Control PPT by Clark E. Adams (modified)

2. Pests and Pest Control- where we’re going • Some definitions • The need for pest control • Pros and Cons of the chemical approach • Alternative pest control methods • Socioeconomic issues in pest management • Pesticides and policy

3. Bottom line • We will need to use chemicals for the foreseeable future, but they definitely come with negative consequences • There are things we can do (ecological control, cultural control, biotechnology, etc) that can lessen our use of pesticides. • There are agencies that regulate pesticides.

4. Formosan Subterranean Termite Invades the French Quarter Another exotic species- Formosa = Taiwan

5. The Need for Pest Control • PEST: Any organism that has a negative effect on human health or economics(again, population influences) • Any organism that is noxious, destructive, or troublesome (note the anthropocentric view here) (although pesticides are usually insecticides) • Plants or animals (see Fig. 16-2) • Formosan termite • Aedes mosquito • Medfly • Vampire weed

6. Pest Control Purposes • Protect our food- quantity and quality • Protect our health • Convenience, b/c we like solid green lawns and flawless apples

8. Approaches to Pest Control- Chemical, Ecological, and Integrated • Chemical technology • Use of chemicals to kill large numbers of the pest • Short-term protection • Environmental and possible health consequences

9. Philosophies of Pest Control • Ecological pest management • Control based on pest life cycle and ecology (dandelion observation) • Control agent may be an organism or chemical (more on next slide) • Integrated Pest Management combines both approaches

10. Philosophies of Pest Control- Ecological Pest Management • Specific to pest and/or to manipulate a part of the ecosystem • Emphasizes protection from pest (not eradication, total victory, extinction, etc.)

11. Promises and Problems of the Chemical Approach • Development of chemical pesticides and their successes • Problems stemming from chemical pesticide use

12. Development of Chemical Pesticides • First-generation pesticides (inorganic) • First attempt at chemical technology • Toxic to humans and agricultural plants (i.e.- ARSENIC!!) • Pests developed resistance

13. Development of Chemical Pesticides • Second-generation pesticides • Used after WW II • Organic chemical • Toxic, but less so, to humans and agricultural plants; persistent • Pests developed resistance

14. 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)

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

16. Aerial Spraying

17. Problems Stemming from Chemical Pesticide Use • Development of resistance by pests • Resurgences (the targeted pest comes back, even worse!) and secondary pest outbreaks (now you have NEW pests, that weren’t pests before) • Adverse environmental and human health effects

18. Resistance • Chemical pesticides lose effectiveness • Resistant pest populations produce next generations- evolution at work.

19. Pesticide Resistance

20. 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. Ex: mites are now a pest .

21. The Bugs Are Coming! Time Magazine, July 12, 1976, page 38

23. The Pesticide Treadmill

24. Human Health Effects • Cancer, dermatitis, neurological disorder, birth defects, sterility, endocrine system disruption, immune system depression. • Agricultural workers suffer acute poisoning during pesticide application. • However, please note that life expectancy HAS risen during the time of greatest pesticide use

25. 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.

26. Environmental Effects • DDT led to the decline in populations of several bird species • Bald eagle • Peregrine falcon • Bioaccumulation- in an individual over time • Biomagnification- increases as you go up the food chain.

27. Biomagnification

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

29. Alternative Pest Control Methods • Cultural control • Control by natural enemies- wasps • Genetic control- by regular or genetic eng. • Natural chemical control- pheromone disrupters

30. Complex Life Cycle of Insects

31. Cultural Control

32. Genetic Control • Plants or animals are bred to be resistant to the attack of pests. • Chemical barriers- the plant doesn’t taste good to the pest, a virus doesn’t reproduce in the plant, etc. • Physical barriers- leafhoppers can’t attack plants with hooked leaf hairs, or kill them with sticky secretions (16-16)

33. Genetic Control • Introduction of genes into crops from other species: transgenic crops. • Sterile males are released into pest population- taking advantage of the sexual tendencies of female screwflies- they only mate once- if they mate with a sterile male- no offspring.

34. Control Using Natural Enemies

40. Natural Chemical Control • Pheromones: 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

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

42. Integrated Pest Management (IPM) • An approach to controlling pest populations using all suitable methods—chemical and ecological—in a way that brings about long-term management of pest populations and also has minimal environmental impact

45. Socioeconomic Issues of Pest Management • Pressures to use pesticides • Integrated pest management • Organically grown food

46. Pesticides and Policy • Fifra: Federal Insecticide, Fungicide, and Rodenticide Act- 1947& 1972 (birth of EPA) • FQPA of 1996: Food Quality Protection Act • Pesticides in developing countries

47. 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

48. What you need to know from Chapter 16:What’s a pest? (What’s anthropocentric?)Chemical vs ecological control? IPM?+ & - of DDT?Resurgence & secondary pestsWhat is an organophosphate like? Define and give/recognize examples of: cultural control, control by natural enemies (biocontrol), genetic control, biotechnologyWhat is considered organic food in the US? 100% organic?What do FIFRA and FQPA regulate? Who do we give special treatment to in FQPA?Is our food COMPLETELY free of things that cause cancer???Just because a pesticide is banned in the US, does that mean it is not sold in developing countries?