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					      LECTURE 9

             Some Definitions
Pesticide = a substance that kills a pest
  (insect, weed, bacteria, nematode…)

     Herbicide = weed killer

     Insecticide = insect killer

     Rodenticide = rodent killer
Why are pesticides used in agriculture,
   society and the environment?
1. Agriculture:

  a. Use of “crop protecting” agents improves yield
     and quality of agricultural products, consumer

  b. Prevents the spread of diseases to crops and
     livestock (Pierce’s Disease)

  c. The use of pesticides is regulated by the E.P.A.
      (Environmental Protection Agency, state law
      and county ordinances)
   Why are pesticides used in agriculture, society and the

2. Society & Environment:

a. Pesticides are used regularly in city parks and
   other recreational areas to control insect damage
   and weeds (ie Disneyland, ball parks, schools,

b. Pesticides are used to protect humans from
   insect-borne diseases, mosquitoes transmit
   many diseases (Mosquito Abatement Programs)
   West Nile Virus, Malaria

c. Rodenticides are used in homes, restaurants and
   hotels to control mice and rats which can spread
   disease, Junta Virus
    Concerns With Pesticide Use
1. Environmental concerns

  a. pesticides can kill beneficial insects and plants
     (non selective)

  b. pollution – runoff of herbicides and
     insecticides into irrigation water and then into
     rivers - damages wildlife habitat

  c. cancer causing agents – organophosphates

  d. disrupt the natural ecosystem and natural

  e. creates chemical resistance – insects
Integrated Pest Management (IPM)

 Pest management that utilizes several
 strategies to control insects and other
 pests rather than strictly relying on
 chemical control.

Four Components…
      Integrated Pest Management (IPM)
1. Pest identification – important for proper
  pest control

     Confuse beneficial insects with harmful

     Pest that’s on the plant may not be the
      one causing damage

     Damage may not even be caused by an
      insect (toxin or nutritional deficiency,
      weather damage etc.)
 Integrated Pest Management (IPM) Components

2. Surveying for pests – systematically
   check for pests and pest damage

     Pheromone traps

     Sweeping the field

     Random leaf, fruit and stem samples
 Integrated Pest Management (IPM) Components

3. Encourage Beneficial Insect/Animal

     Use milder chemicals or selective sprays that
      don’t kill beneficial animals.

     Examples – “Barn Owl Nesting Boxes” –
      rodent control

     Predatory wasp populations – fly control in
      poultry and dairy operations

     Natural insect enemies – lady bugs, lace
      wings, praying mantis, predatory mites
 Integrated Pest Management (IPM) Components

4. Control Action Guidelines –

Application of pesticides only after a certain
 number of pests have been found and
 there is a threat of economic loss.
           Sociology of Pesticides
   Rachel Carlson (1962) – beginning of the modern
    environmental movement - Silent Spring

   DDT – pesticide – “Nobel Prize” in medicine
       Insect/disease control - Potent toxin
       Still used to control mosquitoes in 3rd world countries
       Malaria, Yellow Fever, Dengue Fever – spread by
       Yellow Fever – nearly prevented the colonies from being
       More soldiers were lost in WWII due to mosquitoe borne
        disease than in battle.
         Sociology of Pesticides continued…

   Vietnam War – used defoliants to clear forests

   Post War Conditions – Refugee camps, many diseases

   Modern Challenge…Disease could be used as a
    weapon (biological and chemical agents)

   Bubonic Plague – infected fleas & dropped them on
    China during WWII; killed 50,000 people

   Many people think all pesticides should be banned.

   San Francisco has tried to ban all pesticides; this
    would include germ killers like Chlorine
    Pesticide Routes of Entry

   Dermal (skin) most common

   Oral

   Respiratory

   Ocular
     Pesticide Toxicological Tests

   U.S. food supply is the safest in the world

   “Risk Cup” – EPA evaluate scientifically the
    level of risk compared to benefits.

   Fill the cup with all the risks an individual
    is exposed to during their lives.
           Politics of Pesticides

“Environmental lobbyists” are very powerful in
  Washington D.C.

     Natural Resource Defense Fund – contracted
      with 20/20 to break the story on “Alar” in

     -Alar was banned w/out scientific evidence.

     -Organo Phosphate, carbonate pesticides –
      research based on WWII neurotoxicity studies.
    Politics of Pesticides continued…
   “Biocides” – easily manufactured & inexpensive

   Petroleum industry was the generator

   Pet pesticides – flea control, tick control

   Pharmaceutical industry does much of the
    pesticide research today, patent lasts 17 years &
    it takes 10 years to complete research process.

   How much does this cost?
    Environmental Issues with Pesticides

   Pesticides enter the environment through
    crop application.
        Leach into aquifer

   Central Valley has potential problems
    associated with continual pesticide

   Problem-“Bio-magnification”
   Chlorodane – killed lots of bugs, 30 year half-
    life, very stable in soil. Mis-application of
    insecticide caused it to be banned.

   DDT – stays in the environment, organisms pick
    up the molecules and it stays in the animal’s
    tissues…animals eat animals and it passes
    on…Raptor egg shell thinness

   Resistance develops – kill 99%; 1% left that are
    resistant. Survivals detoxify chemicals used as
    pesticides low kill-rate. “Pesticide treadmill”
        Some Answers to Reducing
              Pesticide Use
   Control populations – work within
    ecological principles, IPM

   Pest Control Advisors must use these
    practices, an old idea.

       Select all the techniques to control pests.
       Understand the ecological interactions of the

   California has now made laws to regulate
           The Future Challenges?
   IPM – “requires people to work smarter” dealing
    with biology & ecology and utilizing…

        “Environmentally Friendly” pesticides
       Mycotoxins – “aflatoxins” naturally occurring
        toxins in peanuts, mushrooms

   Organic Farming – now will be regulated by the
    federal government, fringe element no more.

   “Biotechnology” – fear of the unknown, no risk is
    acceptable according to anti-biotech groups.
  Future of Chemicals & Pesticides
Alternatives will be Key Issue

     Beneficial insects
     Mechanical control
     Chemical controls
     Hedgerows – create a place for native species-
      self perpetuating
     Cover crops that produce nitrogen…lower
      fertilizer use
     Cover crops that encourage beneficial insects...
     Proper irrigation for various crops…reduce

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