PROTECTING FOOD RESOURCES: PEST MANAGEMENT

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PROTECTING FOOD RESOURCES PEST MANAGEMENT

• Organisms found in nature (such as spiders)
  control populations of most pest species as part
  of the earths free ecological services.

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PROTECTING FOOD RESOURCES PEST MANAGEMENT

• We use chemicals to repel or kill pest organisms
  as plants have done for millions of years.
• Chemists have developed hundreds of chemicals
  (pesticides) that can kill or repel pests.
• Pesticides vary in their persistence.
• Each year gt 250,000 people in the U.S. become ill
  from household pesticides.

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Major Types of Pesticides
Type of Pesticide Examples Biomagnified?
Chlorinated hydrocarbons DDT, dieldrin, chlordane Yes
organophosphates Malathion, parathion, diazinon No
Botanicals Rotenone, camphor No
Contact Herbicides Paraquat No
Systemic Herbicides 2,4-D, Roundup No
Fungicide Methyl bromide No
Fumigant Carbon tetrachloride, ethylene dibromide Yes
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PROTECTING FOOD RESOURCES PEST MANAGEMENT

• Advantages and disadvantages of conventional
  chemical pesticides.

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Individuals Matter Rachel Carson

• Wrote Silent Spring which introduced the U.S. to
  the dangers of the pesticide DDT and related
  compounds to the environment.

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The ideal Pesticide and the Nightmare Insect Pest

• The ideal pest-killing chemical has these
  qualities
• Kill only target pest.
• Not cause genetic resistance in the target
  organism.
• Disappear or break down into harmless chemicals
  after doing its job.
• Be more cost-effective than doing nothing.

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Superpests

• Superpests are resistant to pesticides.
• Superpests like the silver whitefly (left)
  challenge farmers as they cause gt 200 million
  per year in U.S. crop losses.

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Pesticides Kill Natural Pest Enemies and Create
New Pests

• Broad-spectrum pesticides kill natural predators
• New pests are unleashed once natural predators
  eliminated
• Currently 100 of the 300 most destructive insect
  pests in the U.S. were secondary pests

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When genetic resistance develops, pesticide sales
representatives usually recommend

• More frequent application of pesticides
• Larger doses of pesticides
• A switch to new chemicals to keep the resistant
  species under control

The result is a pesticide treadmill, whereby the
farmer may pay more and more for a pest control
program
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Where do pesticides go?

• Bottom sediments
• Surface water
• Groundwater
• Air
• Food
• Humans
• Wildlife

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Each Year in the United States Pesticides Applied
to Cropland

• Wipe out 20 of the U.S. honeybee colonies and
  damages another 15
• Kill more than 67 million birds
• Kill 6 14 million fish (runoff from croplands)
• Menace about 20 of the endangered and threatened
  species in the U.S.

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Pesticide Protection Laws in the U.S.

• 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.

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Other Ways to Control Pests

• There are cultivation, biological, and ecological
  alternatives to conventional chemical pesticides.
• Fool the pest through cultivation practices.
• Provide homes for the pest enemies.
• Implant genetic resistance.
• Bring in natural enemies.
• Use pheromones to lure pests into traps.
• Use hormones to disrupt life cycles.

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Other Ways to Control Pests

• Biological pest control Wasp parasitizing a
  gypsy moth caterpillar.

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Advantages of Biological Control

• Focuses on selected target species
• Is nontoxic to other species
• Can be self-perpetuating
• Minimizes genetic resistance

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Disadvantages of Biological Control Agents

• Can take years of research
• Cannot always be mass-produced
• Often are slower acting and more difficult to
  apply
• Must be protected from pesticides sprayed close
  by
• Can multiply and become pests themselves

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Other Ways to 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.

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Using Birth Control to help control pests

1. Males of some insect species are raised in the
   laboratory
2. They are sterilized by radiation or chemicals
3. The sterilized males are released into an
   infested area to mate unsuccessfully with fertile
   wild females

NO LONGER USED
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Case Study integrated Pest Management A
Component of Sustainable Agriculture

• An ecological approach to pest control uses a mix
  of cultivation and biological methods, and small
  amounts of selected chemical pesticides as a last
  resort.

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Why is IPM important?
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Case Study integrated Pest Management A
Component of Sustainable Agriculture

• Many scientists urge the USDA to use three
  strategies to promote IPM in the U.S.
• Add a 2 sales tax on pesticides.
• Establish federally supported IPM demonstration
  project for farmers.
• Train USDA personnel and county farm agents in
  IPM.
• The pesticide industry opposes such measures.

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