Pesticides

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Pesticides

• Brooke LeFevre Victoria Sifuentes Rachel Herron

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Introduction

• What is a Pesticide?
• Any chemical that is used to kill insects,
  animals, fungi.
• Insecticide, Fungicide, rodenticide, and
  herbicides (examples)
• Pest- any organism that is unwanted
• Persistent pesticides that are stable and remain
  active for long periods of time
• Non-persistent pesticides that break down
  quickly
• Target specific pest causing the problem
• Non-target the organism, that is unintentionally
  killed
• Biocide when pesticides kill a large variety of
  things including humans
• Bioaccumulation/Biomagnification

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Insecticides

• Used to control pests that feed on crops or
  carry plant diseases
• Causes prevention of huge losses
• It can be done manually but it is not practical
• In ancient Greece Homer mentioned use of sulfur
  for controlling insects
• Disease carrying insects
• Mosquitoes carry 30 different harmful diseases to
  humans
• Malaria/ bubonic plague/sleeping sickness

• Chlorinated hydrocarbons
• Complex/ stable structured that contain carbon,
  hydrogen, and chlorine.(DDT)(chlordane) (aldrin).
• Believed to affect the nervous system of
  organisms then resulting in death.
• Persistent pesticide

• Organophosphates
• Non persistent
• More toxic
• Interferes with nervous system
• (anthion)(parathion) (diazinon)

• Carbamates
• Non persistant
• More toxic
• Interferes with nervous system
• (Propoxur)(Carbaryl) (Aldicarb)

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Rodenticides

• Target rodents - mice, rats, voles
• Can destroy food supply, bring disease, and
  damage crops in the field
• Warfarin - causes internal bleeding (bait)

• Drawbacks
• Bait is harmful to any organism that eats it,
  including humans (kills nontarget organisms)
• Rodents can become tolerant
• Other organisms can be harmed by consuming
  poisoned rodents

• Benefits
• Prevents disease spread
• Increases crop yield
• Decreases food supply damage
• Makes food more sanitary

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Herbicides

• Targets weeds - unwanted plants
• Agricultural, lawns and gardens, public areas
• 65 of pesticides used in the U.S. are herbicides
• Auxins a plant growth hormone, a lot can
  produce ethylene, which too much of causes harm
  or death

• Benefits
• Dramatically increase crop yield due to less
  competition and less manual labor
• Balancing the ecosystem

• Drawbacks
• Linger in the soil, leach or runoff into water
• Plants can build resistance over time

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Fungicides

• Fungae (the problem)
• Definition Causative agents of crops that reduce
  yield/quality of food groups.
• Can produce toxic compounds unfit to eat
• Methylmercury protects seeds from
  spoilage but highly toxic to
  humans

• Fungicides (the solution)
• Reduce yield losses that are caused by disease
• Improve quality of appearance of harvested
  produce
• Reduces natural toxins fungi produces making it
  safer to eat.
• Protect products from spoilage

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DDT

• Reasons for Use
• First synthetic organic insecticide
• Inexpensive, long lasting, harmless to humans.
  And deadly to insects
• Prevented disease and increased crop yield

• Disadvantages
• Affected nontarget organisms
• Eagles, osprey, peregrine falcons (egg hardness)
• Persistent chemical - Half life of 10-15 years
• Accumulates reaches higher concentrations in
  older animals and higher trophic levels

Silent Spring introduced the dangers of DDT and
related compounds to the environment

• www.youtube.com/watch?vkyYpwOTtaLIfeaturerelate
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