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					Chapter 20 -Pesticides
               What is a pest?
• Pests are living organisms that occur where
  they are not wanted or that cause damage to
  crops or humans or other animals. Examples
  –   insects,
  –   mice and other animals,
  –   unwanted plants (weeds),
  –   fungi, and
  –   microorganisms such as bacteria and viruses.
           What is a pesticide?
• A pesticide is any substance or mixture of
  substances intended for:
   – preventing, destroying, repelling, or mitigating any
• Though often misunderstood to refer only to
  insecticides, the term pesticide also applies to
  herbicides, fungicides, and various other
  substances used to control pests.
• Under United States law, a pesticide is also
  any substance or mixture of substances
  intended for use as a plant regulator,
  defoliant, or desiccant.
Common Types of Pesticides

              • Insecticides – kills
              • Herbicides – kills
              • Fungicides – kills
              • Nematocides – kills
              • Rodenticides – kills
                rodents (rats)
      The groups of pesticides
• Chemical Pesticides
• Biopesticides
         Chemical Pesticides
• Pesticides that are created from non organic
  or biological means
• Examples are Organophosphate Pesticides,
  Carbamate Pesticides, Organochlorine
  Insecticide, and Pyrethroid Pesticides.
• Biopesticides are certain types of pesticides
  derived from such natural materials as animals,
  plants, bacteria, and certain minerals. For
  example, canola oil and baking soda have
  pesticidal applications and are considered
  biopesticides. At the end of 2001, there were
  approximately 195 registered biopesticide active
  ingredients and 780 products. Biopesticides fall into three
  major classes:
   – Microbial pesticides
   – Plant-Incorporated-Protectants (PIPs)
   – Biochemical pesticides
         Microbial pesticides
• Microbial pesticides consist of a
  microorganism (e.g., a bacterium, fungus,
  virus or protozoan) as the active ingredient.
  Microbial pesticides can control many
  different kinds of pests, although each
  separate active ingredient is relatively
  specific for its target pest[s]. For example,
  there are fungi that control certain weeds,
  and other fungi that kill specific insects.
• Plant-Incorporated-Protectants (PIPs) are
  pesticidal substances that plants produce from
  genetic material that has been added to the plant.
  For example, scientists can take the gene for the
  Bt pesticidal protein, and introduce the gene into
  the plant's own genetic material. Then the plant,
  instead of the Bt bacterium, manufactures the
  substance that destroys the pest. The protein and
  its genetic material, but not the plant itself, are
  regulated by EPA.
         Biochemical pesticides
• Biochemical pesticides are naturally occurring substances
  that control pests by non-toxic mechanisms. Conventional
  pesticides, by contrast, are generally synthetic materials
  that directly kill or inactivate the pest. Biochemical
  pesticides include substances, such as insect sex
  pheromones, that interfere with mating, as well as various
  scented plant extracts that attract insect pests to traps.
  Because it is sometimes difficult to determine whether a
  substance meets the criteria for classification as a
  biochemical pesticide, EPA has established a special
  committee to make such decisions.
                              Pest Types
•   Algicides
     – Control algae in lakes, canals, swimming pools, water tanks, and other sites.
•   Antifouling agents
     – Kill or repel organisms that attach to underwater surfaces, such as boat bottoms.
•   Antimicrobials Antimicrobials
     – Kill microorganisms (such as bacteria and viruses).
•   Attractants
     – Attract pests (for example, to lure an insect or rodent to a trap). (However, food is
       not considered a pesticide when used as an attractant.)
•   Biopesticides
     – Biopesticides are certain types of pesticides derived from such natural materials as
       animals, plants, bacteria, and certain minerals.
•   Biocides
     – Kill microorganisms.
•   Disinfectants and sanitizers
     – Kill or inactivate disease-producing microorganisms on inanimate objects.
•   Fungicides
     – Kill fungi (including blights, mildews, molds, and rusts).
•   Fumigants
     – Produce gas or vapor intended to destroy pests in buildings or soil.
        More types of pesticides
• Biocides
   – Kill microorganisms.
• Disinfectants and sanitizers
   – Kill or inactivate disease-producing microorganisms on inanimate
• Fungicides
   – Kill fungi (including blights, mildews, molds, and rusts).
• Fumigants
   – Produce gas or vapor intended to destroy pests in buildings or soil.
• Herbicides
   – Kill weeds and other plants that grow where they are not wanted.
• Insecticides
   – Kill insects and other arthropods.
• Miticides (also called acaricides)
   – Kill mites that feed on plants and animals.
The last bunch of Pesticide Types
• Microbial pesticides
   – Microorganisms that kill, inhibit, or out compete pests, including
     insects or other microorganisms.
• Molluscicides
   – Kill snails and slugs.
• Nematicides
   – Kill nematodes (microscopic, worm-like organisms that feed on
     plant roots).
• Ovicides
   – Kill eggs of insects and mites.
• Pheromones
   – Biochemicals used to disrupt the mating behavior of insects.
• Repellents
   – Repel pests, including insects (such as mosquitoes) and birds.
• Rodenticides
   – Control mice and other rodents.
        Pesticide Generations
• The first generation of pesticides were
  basically natural pesticides that were
  extracted from plants that were fighting
  against pests from the beginning
• The second generation of pesticides that
  were created chemically. A prime example
  is DDT, which is a potent insecticides that
  was known about since 1874
        The risks of Pesticides

• By their nature, most pesticides
  create some risk of harm - Pesticides
  can cause harm to humans, animals, or
  the environment because they are
  designed to kill or otherwise adversely
  affect living organisms.
     The benefits of Pesticides
• However, pesticides are useful to
  society - Pesticides can kill potential
  disease-causing organisms and control
  insects, weeds, and other pests. It also
  helps to prevent from a deterioration of
  How are we exposed to pesticides?
• Pesticides can be found, often in small amounts,
  almost anywhere worldwide. Where you live and your
  lifestyle largely determines the potential for exposure
  to pesticides.
• People are not intentionally exposed to pesticides,
  except for public health reasons. Instructions on the
  pesticide label are designed to minimize exposure,
  both to workers and the general public.
• Most non-occupational exposure comes from food or
  home pesticide use. In addition to use in agriculture
  and forestry, pesticides are used in many public
  places, including office buildings, restaurants,
  schools, parks, golf courses, and along roads, railroads
  and power lines.
 Pesticides are found everywhere
• You may think that
  pesticides are only used in
  the field however it is also
  commonly used within the
  household. For instance,
  when you go camping and
  you bring bug repellent,
  that is a type of pesticide.
  Another example is Raid,
  which can kill unwanted
  household pests.
Most of the foods we eat have been grown with the use of
pesticides. Therefore, pesticide residues may be present
inside or on the surfaces of these foods.

Home and Personal Use Pesticides
You might use pesticides in and around your home to
control insects, weeds, mold, mildew, bacteria, lawn and
garden pests and to protect your pets from pests such as
fleas. Pesticides may also be used as insect repellants
which are directly applied to the skin or clothing.
• Pesticides in Drinking Water
  Some pesticides that are applied to farmland or other land
  structures can make their way in small amounts to the
  ground water or surface water systems that feed drinking
  water supplies.

• Worker Exposure to Pesticides
  Pesticide applicators, vegetable and fruit pickers and
  others who work around pesticides can be exposed due to
  the nature of their jobs. To address the unique risks
  workers face from occupational exposure, EPA evaluates
  occupational exposure through a separate program. All
  pesticides registered by EPA have been shown to be safe
  when used properly.
        The fight for pesticides
          on human health
• Many people argue that pesticides have
  more benefits that risks.
• They believe that pesticides can help save
  lives by preventing almost “7 million
  people from pre-mature deaths”
• They help to prevent illness from insect-
  transmitted diseases such as malaria,
  bubonic plague, typhus, and more.
        The fight for pesticides
        on an agricultural basis
• Pesticides lower food costs and increase
  food supplies
  – This is because pests destroy about 55% of the
    world’s potential food supply.
• Without the usage of pesticides, the damage
  from pests would rise significantly and food
  costs would rise significantly because of the
  damage that we would receive from pests.
        The fight for pesticides
          on a business basis
• Pesticides increase profits for farmers.
• Pesticide companies estimate that for every
  one dollar that is spent on pesticides, there
  is a four dollar profit from the crops that
  farmers grow. This not only would increase
  crop yield but would also help pesticide
  companies profit and farmers to grow their
  crops in peace.
                      Health risks
• Over 19% of commercial lettuce
  from major grocery store chains
  contained the pesticide DDT or
  DDE - Approximately 75% of all
  produce tested positive for various
  pesticide residues. Although
  research suggests these levels can
  affect humans, the EPA does not
  currently require chemical
  companies to test their chemicals
  for immune system damage or
  subtle neurological harm.
The benefits of pesticides out-weigh
          the health risks
• Right now companies, although are not obligated
  to be tested for their chemical damages to the
  human immune system, believe that “the reality is
  that pesticides, when used in the approved
  regulatory manner, pose no risk to either farm
  workers or consumers”.
• Another reason they believe that pesticides are
  more beneficial then detrimental is because
  companies are developing “safer and more
  effective pesticides”.
  The fight against pesticides due to
          genetic resistance
• The opponents of pesticides believe that the
  biggest problem of pesticides, is that they cause
  genetic resistance among the pests that they
  control. They believe that since insects breed
  rapidly, they come back even stronger each time
  because of genetics and evolution. A prime
  example is the cockroach and their incredible
  ability to create resistance against most of the bug
  sprays that it is faced against, and how they have
  survived for so many eons.
 Fight against pesticides in that they
    do not target singular insects
• Opponents believe that “another problem with
  pesticides is that there are broad-spectrum
  insecticides that kill natural predators and parasite
  that may have been maintaining the population of
  a pest species at a reasonable level”.
• They also believe that wiping out natural predators
  cal also unleash new pest whose populations the
  predators had previously held in check, causing
  other unexpected effects.
        Pesticide Treadmills
   The threat to farmer’s business
• One of the risks of using pesticides is the
  constant and rising costs of pesticides.
• Since pests can grow resistance to
  pesticides, farmers may undergo a program
  where they must purchase more pesticides
  to apply a larger dose, however they dosage,
  no matter how large, becomes more and
  more ineffective.
 Pesticides hurt the environment
• One of the major problems is that “pesticides
  don’t stay put”
• According to the U.S. Department of Agriculture,
  no more than 2% of the insecticides applied to
  crops by aerial spraying or by ground actually
  reaches the target pests.
• Pesticides that miss their target pests end up in the
  air, surface water, groundwater, bottom sediments,
  food, and nontarget organisms, including humans
  and wildlife
Health Problems Pesticides may Pose

• Laboratory studies show that pesticides
  can cause health problems, such as
  birth defects, nerve damage, cancer,
  and other effects that might occur over
  a long period of time. However, these
  effects depend on how toxic the
  pesticide is and how much of it is
• For these reasons, the Federal Government,
  in cooperation with the States, carefully
  regulates pesticides to ensure that their use
  does not pose unreasonable risks to human
  health or the environment. In particular, the
  Federal pesticide program is designed to
  ensure that these products can be used with
  a reasonable certainty that they will pose no
  harm to infants, children, and adults.
 How does the environment break
       down pesticides?
• In the atmosphere, most pesticides breakdown
  rapidly by reaction with oxygen or free radicals,
  catalyzed by sunlight (indirect photolysis). Some
  pesticides break down by directly absorbing
  sunlight (photolysis). Those that persist can travel
  long distances in the atmosphere. In water,
  breakdown is usually by hydrolysis, often
  mediated by pH. In aquatic systems, pesticide
  break down by microorganisms in sediments may
  also be important. The predominant pathway in
  soil is microbial degradation, although for some
  pesticides chemical degradation is important.
How the Government Regulates Pesticides?

• Before a company can sell or distribute any
  pesticide in the United States of America,
  EPA must review studies on the pesticide
  to determine that it will not pose
  unreasonable risks to human health or the
  environment. Once EPA has made that
  determination, it will license or register that
  pesticide for use in strict accordance with
  label directions.
    Other Solutions to pest control

•   Crop rotation
•   Trap Crops
•   Intercropping
•   Cross breeding plants
•   Introduce natural enemies
•   Insect birth control
•   Hot water can “zap” pests
   Crop Rotation and protection
• Crop rotation is when the type of crop
  planted in a field each year can be changed.
• Another method is to plant rows of hedges
  or trees can be planted around fields to
  hinder insect invasions and provide habitats
  for their natural enemies.
               Trap Crops
• Trap crops are basically planted to lure
  pests away from the main crop, that is
  usually human food supply. For example,
  in Nicaraguan cotton fields several rows of
  cotton are planted several months ahead of
  the regular crop to attract boll weevils,
  which can then be destroyed by hand or
  with small doses of pesticides.
• Growers cal switch from vulnerable
  monocultures to intercropping, agroforestry,
  and polyculture, which use plant diversity to
  reduce losses to pests. The diseased or
  infected plants and stalks and other crop
  residues that harbor pests can then be
  removed from the crop field.
• Benefits
  – Plants and animals that are genetically resistant to
    certain pests, insects, fungi, and diseases can be
    developed. This would then lower the costs of
    pesticides and remove many fears of health risks
• Risks
  – However, resistant varieties usually take a long time
    and lots of money to develop by conventional
    crossbreeding methods. More over, if the
    crossbreeding fails, then more research has to be done
    in order for success, which in the end would take more
    money to accomplish
            Natural Predators
• Biological control using predators, parasites, and
  pathogens can be encouraged or imported to
  regulate pest populations. More than 300
  biological pest control projects worldwide have
  been successful, especially in China and Cuba.
• Biological control has several advantages because
  each predator focuses on select target species and
  also this method is nontoxic to other species and
  also to humans.
         Insect Birth Control
• Males of some insects pest species can be
  raised in the laboratory, sterilized by
  radiation or chemicals. And then released
  into an infest area to mate unsuccessfully
  with fertile wild females. This technique
  works best if the females mate only once
  because once they fail, they fail and the
  females will not search for another mate
  that may be fertile.
                 Hot water?
• Some farmers have begun using the aqua
  heat machine, which sprats boiling water on
  crops to kill weeds and insects. Water is
  boiled and drawn from a large stainless steel
  tank mounted on a tractor and sprayed on
  crops using a long boom.
  – So far it has worked well on cotton, alfalfa, and
    potato fields and in citrus groves in Florida,
    where the machine was invented.
  Are Some Pesticides Safer Than
• Biologically-based pesticides, such as
  pheromones and microbial pesticides, are
  becoming increasingly popular and often
  are safer than traditional chemical
  pesticides. In addition, EPA is registering
  reduced-risk conventional pesticides in
  increasing numbers.
What is "Integrated Pest Management“?
• Age-old, common-sense practices are what many people
  associate with IPM. Today many growers no longer apply
  pesticides to food on a regular basis regardless of whether
  or not there are insects, weeds, or other pest problems. In
  some parts of the country, food is being marketed as IPM
• Some practices for preventing pest damage may include:
• inspecting crops and monitoring crops for damage, and
• In technical terms, Integrated Pest Management (IPM) is
  the coordinated use of pest and environmental information
  with available pest control methods to prevent
  unacceptable levels of pest damage by the most
  economical means and with the least possible hazard to
  people, property, and the environment.
 How can IPM help control pests
• First keep in mind that IPM is a plan that is
  evaluated as if the crop and its environment
  is an ecological system.
• Basically the overall purpose of IPM is not
  the eradication of pests but the reduction of
  crop damage to an economically tolerable
NO MORE~~~!!!!