Protecting Food Resources:

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Protecting Food Resources

• Pesticides and Pest Control

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Pesticides Types and Uses

• What is a Pest?
• A pest is any species that competes with us for
  food, invades lawns and gardens, destroys wood in
  houses, spreads disease, or is simply a nuisance
• Most of the time nature takes care of the pests
  through natural enemies (predators, parasites,
  and disease organisms)

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So whats a Pesticide?

• Pesticides (also known as biocides) are chemicals
  that are to kill organisms we consider
  undesirable
• ex. insecticides, herbicides, fungicides,
  nematocides, and rodenticides

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Above Worker prepares his vehicle for a day of
pesticide spraying
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Coevolution

• For almost 225 million years, plants have been
  producing chemicals to ward off or poison
  herbivores that feed on them
• But, through what is known as coevolution, the
  predators overcome various plant defenses by
  natural selection and the plants must develop new
  defenses

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First Attempts at Pesticides

• Sulfur (early 500 BC)
• Toxic compounds of arsenic, lead, and mercury
  (1400s)
• Abandoned in late 1920s when the increasing
  number of human poisonings increased
• Nicotine Sulfate (1600s)
• Pyrethrum and Rotenone (mid-1800s)

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Paul Mueller and the Second Generation

• In 1939 Paul Mueller discovered that DDT, a
  chemical known since 1874, was in fact a potent
  insecticide. DDT became the first pesticide of
  the so-called Second Generation Pesticides.
  Mueller went on to win the Nobel Prize in 1948
  for his discovery.

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Pesticides Today

• Chemists have been developing hundreds of
  synthetic organic chemicals for use as pesticides
• Worldwide about 2.3 million metric tons of
  pesticides are used yearly
• 1 lb for each person on earth
• 75 in developed countries (Latin America, Asia
  and Africa on the rise)
• 1996 world sales 30 billion(11 billion US)

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Spray those fields
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Here in the US

• About 630 different biologically active (pest
  killing) ingredients and about 1,820 inert
  (inactive) ingredients are mixed to make some
  25,000 different pesticide products in the United
  States

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Pesticide Distribution in US

• Cultivation of two crops
• Cotton (55)
• Corn (35)
• Used about 90 of the insecticides and 80 of the
  herbicides applied to crops in the United States
  in 1995

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Example of Solid Pesticides
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More Distribution

• 25 of the pesticide use in the United States is
  for ridding houses, gardens, lawns, parks,
  playing fields, swimming pools, and golf courses
  of unwanted pests
• Average lawn in US 10xs more pesticides per
  hectare than US cropland
• Each year 250,000 residents become ill

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Some Quick Facts

• Broad-Spectrum agents toxic to many species
• Selective or Narrow spectrum agents effective
  against a narrowly defined group of organisms
• Pesticides vary in persistence (length of time
  they remain deadly in environment)

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The Pros

• Pesticides save human lives has prevented
  premature births due to malaria, bubonic plague,
  typhus, sleeping sickness (all carried by pests)
• Pesticides increase food supplies and lower food
  costs 55 of crop lost before harvest due to
  pests
• Pesticides increase profits for farmers every 1
  spent on pesticides yields worth approximately
  4 (although dropped to 2 if harmful effects)

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Farmers in all countries have tried pesticides to
save there crops
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More Pros

• Pesticides work faster and better than
  alternatives Pesticides can control pests
  quickly and at a reasonable cost. Long shelf life
  and easily shipped and applied
• Health risks insignificant when compared to their
  benefits
• Safer more effective pesticides are being
  developed
• New pesticides are being used in less rates per
  unit when compared to older products

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Ultimate Goal of Pesticides

• Kill only the target pest
• Harm no other species
• Disappear or break down into something harmless
  after doing its job
• Not cause genetic resistance in target
• Be cheaper than doing nothing

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The Cons

• Genetic Resistance pest organisms develop
  resistance to the pesticide after a short period
  of being exposed to it
• Broad-Spectrum insecticides kill natural
  predators and parasites that may have been
  maintaining the population of a pest species at a
  reasonable level
• Ex. Wolf spiders, wasps, predatory beetles

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Cons continued

• Because natural predators can be wiped out this
  may unleash new pests whose populations the
  predators had previously held in check

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In Our Water

• Testing in rivers and water reveal that
  pesticides have strayed away from there targets
  and found there way into the waters

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Pesticide Treadmill

• As pests become resistant to the pesticides,
  sales reps for the pesticide recommend larger
  doses or more frequent application
• As a result farmers end up on a pesticide
  treadmill where they end up paying more and more
  for a pest control program that often becomes
  less and less effective

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Example of Pesticide Treadmill

• In Central America, cotton growers increased
  the frequency of insecticide applications from 10
  to 40 times per growing season. Still, declining
  yields and falling profits forced many of the
  farmers into bankruptcy

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Where does it all go?

• Only about 2 of the sprayed insecticide by air
  reaches target pests
• Less than 5 of herbicides applied reach target
  weed
• Pesticides that dont reach there target end up
  in the air, surface water, groundwater, bottom
  sediments, food and other nontarget organisms

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Continued

• Still, pesticide waste can be reduced by using
  recirculating sprayers, covering spray booms, and
  using rope-wick applicators

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DDT

• Banned in 1972 by US
• 1980 high levels in peregrine falcon and the
  osprey
• EPA found DDT in 99 of the freshwater fish it
  tested
• DDT drifts from other countries still using it

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Checking for pesticide residue in food
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Regulation in the US

• All commercial pesticides must be approved by EPA
• EPA reviews each pesticide
• EPA sets tolerance levels amount of toxic
  pesticide residue that can legally remain on crop
• No longer has to test on birds and fish
• 55 active pesticides banned in US, but may be
  used and shipped elsewhere

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More Regulations

• National Academy of Sciences says that the
  federal laws are not adequate
• 98 of potential risk of cancer would be
  eliminated if pesticide residue on food
  eliminated by government
• Approximately 1 Billion spent on regulating
  pesticides each year

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1996 Food Quality Protection Act

• Requires food to have only reasonable levels of
  pesticide tolerance
• It requires manufacturers to demonstrate that the
  active ingredients in there products are safe for
  infants and children
• Requires EPA to consider exposure to more than
  one pesticide when setting pesticide tolerance
  levels
• EPA develops program to screen ingredients

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From Above

• Just one of the many ways that pesticides are
  being applied are through aerial drops of the
  chemicals

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Other Solutions

• Crop rotations
• Planting times can be adjusted
• Plowing at night (reduces weeds)
• Plant where major pests do not exist
• Switch away from monoculture to intercropping,
  agroforestry, and polyculture

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More Solutions

• Plants and animals that are genetically resistant
  to certain pest insects, fungi and diseases can
  be developed
• - downside costly
• Biological control predators and pathogens
• 300 biological pest control successful in China
  and Cuba
• Biological Control non-toxic to humans
• Downside timely

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Pesticides are plentiful as seen here and it
comes in many different forms
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Even more Solutions

• Plant toxins
• Bt toxin used to kill thousands of strain of
  common soil bacterium
• Insect Birth Control (sterile male approach)
• Aqua heat spray boiling water on crops

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Yes more solutions

• Some crops can be exposed to gamma rays after
  harvest
• Extends shelf life
• Critics say irradiating food destroys vitamins
  and other nutrients
• Increases death from botulism poisoning
• Picowaved stickers on food that has been

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IPM

• Integrated Pest Management
• Goal is reduction of crop damage t an
  economically tolerable level
• Carefully monitor damage levels of pests
• When reached, farmers first use biological
  methods
• Small amounts of insecticides are used as a last
  resort

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Pesticides in Politics

• Pesticides have been a big issue with
  environmentally safe activists. It is a big topic
  the EPA has to deal with