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Chapter 20 Pesticides


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Title: Chapter 20 Pesticides

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 include
  • 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 pest.
  • 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 insects
  • Herbicides kills weeds
  • Fungicides kills fungus
  • Nematocides kills round-worms
  • 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 pests. For
    example, there are fungi that control certain
    weeds, and other fungi that kill specific

Plant-Incorporated-Protectants (PIPs)
  • 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
  • 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
  • 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 objects.
  • 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
  • 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 vegetation

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.

Food 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
  • 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 pesticideson 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
  • This is because pests destroy about 55 of the
    worlds 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 pesticideson 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
  • 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
  • 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
  • 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 TreadmillsThe threat to farmers
  • 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
    dont 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 consumed

  • 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

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

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
  • 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 Others?
  • 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 food.
  • Some practices for preventing pest damage may
  • inspecting crops and monitoring crops for damage,
  • 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 level.

  • NO MORE!!!!