The  Pesticide Dilemma Chapter 22
What is a Pesticide? <ul><li>Pests  are any type of organism that interferes with humans in some way. </li></ul><ul><li>Pe...
Range of pesticides <ul><li>Narrow-spectrum pesticides : </li></ul><ul><ul><li>Kills organisms it was intended to.  </li><...
Major types of Herbicides <ul><li>Broad Leafed Herbicides </li></ul><ul><ul><li>Kill plants with broad leaves but leave gr...
Effect of use of Herbicides in Vietnam <ul><ul><li>Agent orange  was sprayed  over jungles to kill vegetation. </li></ul><...
Benefits of Pesticides <ul><li>Disease control </li></ul><ul><ul><li>Mosquitoes  are effective vectors of many diseases, s...
Evolution of Genetic Resistance <ul><li>Pesticide treadmill </li></ul><ul><li>(pest becomes resistant so pesticide needs t...
<ul><li>Imbalances in Ecosystems </li></ul><ul><ul><ul><li>Pesticides also tend to  kill the natural predators  of the pes...
<ul><ul><li>DDT was sprayed onto lemon trees but allowed a  scale insect  to proliferate. </li></ul></ul>
<ul><li>Bioaccumulation: </li></ul><ul><ul><li>Most synthetic pesticides are unable to be broken down by bacteria. </li></...
Mobility in the Environment   (land  ->  air  ->  water)
Short-term Effects of Pesticides: Handling of food with pesticide residue   can result in headache, vomiting,  diarrhea etc.
Bhopal, India disaster 1984 <ul><li>40 tons of poisonous gas  was released from a Union Carbide pesticide plant after wate...
Long-term Effects of Pesticides <ul><li>Higher risk of cancer </li></ul><ul><li>Sterility </li></ul><ul><li>Miscarriage / ...
Alternatives to Pesticides <ul><li>Using Cultivation Methods to Control Pests </li></ul><ul><li>Intercropping </li></ul><u...
<ul><li>Biological Controls </li></ul><ul><li>Using naturally occurring diseases, parasites, or predators to control a pes...
<ul><li>Genetic Controls (GMOs)  – resistant to pests </li></ul><ul><li>Quarantine  – restriction of the importation of ex...
<ul><li>Integrated Pest Management  ( IPM ) </li></ul><ul><li>Identifies the best practices of biological, cultivation & p...
IPM & Rice Production in Indonesia IPM introduced 1987 I <ul><li>Rice production good </li></ul><ul><li>Pests declined </l...
Laws Controlling Pesticide Use <ul><li>Food, Drug, and Cosmetics Act (1938)  – only recognized the  need to regulate  pest...
The Manufacture & Use of Banned Pesticides <ul><li>Some US companies still make banned or seriously restricted pesticides ...
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Chapter22 Pp Presentation

  1. 1. The Pesticide Dilemma Chapter 22
  2. 2. What is a Pesticide? <ul><li>Pests are any type of organism that interferes with humans in some way. </li></ul><ul><li>Pesticides are the toxic chemicals that we use to decrease the numbers of pests. </li></ul><ul><ul><li>Types: Herbicides, Insecticides, fungicides and rodenticides </li></ul></ul><ul><ul><li>Some are botanicals (ex: from plants) – nicotine and pyrethrin (ex: from flowers) </li></ul></ul><ul><ul><li>Some are synthetic – DDT first used in 1939; we didn’t learn of persistence & harm until 1962, Silent Spring. </li></ul></ul>
  3. 3. Range of pesticides <ul><li>Narrow-spectrum pesticides : </li></ul><ul><ul><li>Kills organisms it was intended to. </li></ul></ul><ul><li>Broad-spectrum pesticides : </li></ul><ul><ul><li>Kills a variety of organisms. </li></ul></ul><ul><ul><li>Most pesticides, such as Round-Up </li></ul></ul>
  4. 4. Major types of Herbicides <ul><li>Broad Leafed Herbicides </li></ul><ul><ul><li>Kill plants with broad leaves but leave grasses alone. </li></ul></ul><ul><ul><ul><li>(Tend to mimic growth hormones & disrupt metabolism.) </li></ul></ul></ul><ul><li>Grass Herbicides : kill grasses but leave broad leaves alone. </li></ul>
  5. 5. Effect of use of Herbicides in Vietnam <ul><ul><li>Agent orange was sprayed over jungles to kill vegetation. </li></ul></ul><ul><ul><li>It also contained a compound called dioxin , which had severe effects on the Vietnamese and war Veterans. </li></ul></ul><ul><ul><ul><li>The jungles are about 30% reduced today. </li></ul></ul></ul><ul><ul><ul><li>Besides birth defects and cancer, the compound is still present within the population; Some Vietnamese have about 1800 ppt. </li></ul></ul></ul><ul><ul><ul><li>Typically normal people have about 4 ppt. </li></ul></ul></ul>
  6. 6. Benefits of Pesticides <ul><li>Disease control </li></ul><ul><ul><li>Mosquitoes are effective vectors of many diseases, such as malaria in the tropics </li></ul></ul><ul><ul><li>DDT effectively kills mosquitoes. </li></ul></ul><ul><ul><ul><li>But the banning of DDT allowed for the return of malaria. </li></ul></ul></ul><ul><li>Crop production </li></ul><ul><li>- Farmers save $3-$5 in crops for every $1 </li></ul><ul><li>invested in pesticides </li></ul>
  7. 7. Evolution of Genetic Resistance <ul><li>Pesticide treadmill </li></ul><ul><li>(pest becomes resistant so pesticide needs to be increased &/or it’s chemistry improved) </li></ul>
  8. 8. <ul><li>Imbalances in Ecosystems </li></ul><ul><ul><ul><li>Pesticides also tend to kill the natural predators of the pests by starvation . </li></ul></ul></ul>
  9. 9. <ul><ul><li>DDT was sprayed onto lemon trees but allowed a scale insect to proliferate. </li></ul></ul>
  10. 10. <ul><li>Bioaccumulation: </li></ul><ul><ul><li>Most synthetic pesticides are unable to be broken down by bacteria. </li></ul></ul><ul><ul><ul><li>Slowly this compound will </li></ul></ul></ul><ul><ul><ul><li>increase in concentration </li></ul></ul></ul><ul><ul><ul><li>in soil and organisms . </li></ul></ul></ul><ul><li>Biomagnification: </li></ul><ul><li>aka Biological amplification </li></ul><ul><li>- Increase in pesticide concentration as it passes through the food chain. </li></ul><ul><li>- Many countries subsidize pesticides, hoping for larger crops. </li></ul>
  11. 11. Mobility in the Environment (land -> air -> water)
  12. 12. Short-term Effects of Pesticides: Handling of food with pesticide residue can result in headache, vomiting, diarrhea etc.
  13. 13. Bhopal, India disaster 1984 <ul><li>40 tons of poisonous gas was released from a Union Carbide pesticide plant after water leaked into storage tank, causing a massive explosion </li></ul><ul><li>covering 30 mi 2 . </li></ul><ul><li>600,000 people exposed , many with health problems, especially blindness; 2500 immediately killed. </li></ul><ul><li>UC paid $500 to each victim but have </li></ul><ul><li>not cleaned up the land & groundwater. </li></ul>
  14. 14. Long-term Effects of Pesticides <ul><li>Higher risk of cancer </li></ul><ul><li>Sterility </li></ul><ul><li>Miscarriage / birth defects </li></ul><ul><li>Higher risk for Parkinson’s disease </li></ul><ul><li>Acts as an endocrine disrupter , altering reproductive capabilities </li></ul><ul><li>Suppresses development of intelligence & motor skills of children </li></ul>
  15. 15. Alternatives to Pesticides <ul><li>Using Cultivation Methods to Control Pests </li></ul><ul><li>Intercropping </li></ul><ul><li>Strip cutting (harvest one segment at a time) </li></ul><ul><li>Planting, fertilizing & irrigating at proper time </li></ul><ul><li>Crop rotation </li></ul>
  16. 16. <ul><li>Biological Controls </li></ul><ul><li>Using naturally occurring diseases, parasites, or predators to control a pest. </li></ul><ul><li>Be careful introducing exotics! </li></ul><ul><li>Pheromones and Hormones </li></ul><ul><li>Use pheromones to attract insects to traps </li></ul><ul><li>Synthetic hormones induce abnormal </li></ul><ul><li>development </li></ul><ul><li>Reproductive Controls </li></ul><ul><li>Sterile-male technique – inundate pest population with large numbers of sterile males </li></ul>
  17. 17. <ul><li>Genetic Controls (GMOs) – resistant to pests </li></ul><ul><li>Quarantine – restriction of the importation of exotic plants & animal materials that might harbor pests. </li></ul><ul><li>Irradiating foods – especially meat, kills many organisms </li></ul>
  18. 18. <ul><li>Integrated Pest Management ( IPM ) </li></ul><ul><li>Identifies the best practices of biological, cultivation & pesticide control for each crop . </li></ul><ul><li>The pest is managed, not eradicated . Minimal crop damage is expected. </li></ul><ul><li>Initially requires a lot of money and time for each complete study. </li></ul>
  19. 19. IPM & Rice Production in Indonesia IPM introduced 1987 I <ul><li>Rice production good </li></ul><ul><li>Pests declined </li></ul>
  20. 20. Laws Controlling Pesticide Use <ul><li>Food, Drug, and Cosmetics Act (1938) – only recognized the need to regulate pesticides. </li></ul><ul><li>Pesticide Chemicals Amendment (1954) – established legal limits of pesticidal residue. </li></ul><ul><li>Federal Insecticide, Fungicide, and Rodenticide Act (1947) (FIFRA) – regulated the effectiveness of pesticides. </li></ul><ul><li>Food Quality Protection Act – studies all possible negative aspects of pesticides , including </li></ul><ul><li>smaller legal limits of pesticidal residue </li></ul><ul><li>injested by children. </li></ul>
  21. 21. The Manufacture & Use of Banned Pesticides <ul><li>Some US companies still make banned or seriously restricted pesticides and export the product. </li></ul><ul><li>This can potentially lead to the importation of food tainted with banned pesticides, known as the Circle of Poison . </li></ul>

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