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    Isolation of Naturally Occuring Pesticides & Insecticides
    Middle and High School Lab Experiments
    For Science Labs, Lesson Plans, Class Activities & Science Fair Projects







    Isolation of Naturally
    Occuring Pesticides


    Developers:

    Andrea Martin
    Abington Friends School
    Jenkintown, PA

    Dr. Paul Reibach
    Dr. Diana Bender
    Rohm and Haas Company
    Spring House, PA


    Grade
    Levels:

    Grades 7 - 12


    Discipline:

    Biology, Environmental Science, Ecology


    Goals:

    To show that insecticides occur in nature.


    Materials:

    Mortar and pestle (for plants)
    Sand
    Acetone
    Corn Oil (Mazola�)
    4-oz. jars
    Drosophila melanogaster
    Instant Drosophila food
    Cotton
    Squirt bottle containing water
    1 package of cheesecloth
    125-ml Erlenmeyer flasks
    7-cm funnel
    Gloves
    Electric coffee or spice grinder (for spices)

    Spices: peppercorns 5 g., fennel seeds 5 g, cumin seeds 5 g.

    Plants: Chrysanthemum flowers 10 g, Marigold leaves 5 g,
    Marigold flowers 5 g.


    Procedure:

    1. Make up stock solution of corn oil/acetone: add 0.5 ml corn oil to 100 ml acetone
    2. Weigh out 5 grams of each sample - fennel, cumin, pepper, marigold leaves, flowers and a 10-gram sample of chrysanthemum flowers.
    3. Processing of Samples

      a. Plants
      Put plant sample in mortar, sprinkle some sand over the sample and grind until thoroughly crushed, about 2 minutes.

      Add 10 ml of acetone and grind thoroughly, being careful not to splash liquid. If the mixture is too thick, add 5 more ml of acetone. Strain the acetone/extract mixture by pouring though cheesecloth in a funnel on top of a 125-ml Erlenmeyer flask. After most of the liquid has drained into the flask, extract the remaining liquid by forming a bag around the plant material and squeezing (make sure that you wear gloves). The liquid in the flask is your extract.


      b. Spices
      Grind spice sample in grinder until pulverized. Transfer ground sample to a jar using a spatula. Add 10 ml of acetone and stir mixture well (about thirty seconds). Strain the acetone/extract mixture by pouring through cheesecloth in a funnel, on top of a 125-ml Erlenmeyer flask. After most of the liquid has drained into the flask, extract the remaining liquid by forming a bag around the plant material and squeezing (make sure that you wear gloves). The liquid in the flask is your extract.

    4. Mix 1 ml of the extract with 0.5 ml of corn/acetone stock solution. Pour into a 4-oz jar.
    5. Quickly twirl jar in a hood to evaporate the acetone. The oil/extract mixture should coat the sides of the jar.
    6. Add dry instant food so that it just covers the bottom of the jar. Carefully add water until the food has been hydrated.
    7. Add 20 Drosophila melanogaster adults to the jar and stopper with cotton. They should be awake (see Teacher Note). Record results after 5, 10, 15, 60 minutes and 24 hours.
    8. Control: 0.5 ml corn oil and 1 ml acetone. Coat sides of jar and add food.


    Extensions:

    1. Try different plants and different plant parts.
    2. Try different spices.
    3. Capture different species of wild Drosophila and test them.
    4. Use different types of insects.
    5. Try chromatography of extracts.
    6. Instead of corn oil use Kimwipes�. A Kimwipe� is saturated with 1 ml of extract. The Kimwipe� is then spread out in the hood and dried for 10 minutes. The Kimwipe� is then placed in the bottom of the jar and saturated with 1.5% sugar (sucrose) solution. Be careful not to get any water on the sides of the jar. Add 20 adult Drosophila melanogaster to the jar and put in cotton stopper. Record results as above.


    Safety Considerations:

    Teacher should advise students to avoid breathing acetone vapors or getting acetone on their skin.


    Teacher Note:

    Anesthetize flies ahead of time and place 20 in a fly vial for each extract. Transfer of live flies is best achieved by placing a funnel on the jar with the extract. The fly vial is then tapped to cause flies to drop to the bottom, and the cotton is removed. The vial is quickly inverted onto the funnel. Gently tap the jar to cause the flies to drop into it. (see figure).


    Drosophilia Insecticide
    Data Sheet

    Test Substance_____________Scientist Names:______________________

    Initial numbner of flies:____________

    Time in Hours

    Dead Flies

    % Dead Flies

    Study start time

    _______________

    ___________

    ___________

    ___________

    Observation times

    _______________

    ___________

    ___________

    ___________

    _______________

    ___________

    ___________

    ___________

    _______________

    ___________

    ___________

    ___________

    _______________

    ___________

    ___________

    ___________

    _______________

    ___________

    ___________

    ___________

    _______________

    ___________

    ___________

    ___________

    _______________

    ___________

    ___________

    ___________


    Visual Symptoms or Comments

    _____________________________________________________


    _____________________________________________________


    _____________________________________________________


    _____________________________________________________


    _____________________________________________________


    Drosophilia Insecticide
    Data Sheet

    Test Substance_CUMIN_Scientist Names:_Martin, Bender, Reibach_

    Initial numbner of flies:___25______

    Time in Hours

    Dead Flies

    % Dead Flies

    Study start time

    _1:30 pm _8-8-91_

    ____0______

    ____0______

    ____0______

    Observation times

    _______________

    ___________

    ___________

    ___________

    _2:30 pm _8-8-91_

    ____1______

    ____3______

    ____12_____

    _3:30 pm _8-8-91_

    ____2______

    ____8______

    ____32_____

    _8:30 am _8-8-91_

    ___19______

    ___15______

    ____60_____

    10:30 am _8-8-91_

    ___21______

    ___25______

    ___100_____

    _1:30 am _8-8-91_

    ___24______

    ___25______

    ___100_____


    Visual Symptoms or Comments

    _____________________________________________________


    _____________________________________________________


    _____________________________________________________


    _____________________________________________________


    _____________________________________________________







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