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Published byCorey Magdalene Howard Modified over 9 years ago
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Pesticides
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Pests Any organism that: 1.competes with us for food 2.Invades lawns and gardens 3.Destroys wood in houses 4.Spreads disease 5.A nuisance
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Pea Aphids
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Gypsy Moth Caterpillar
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Emerald Ash Borer
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Pesticides Kill pests (undesirable orgs) Insecticides: kills insects Herbicides: kills weeds Fungicides: kills fungus Nematocides: kills worms Rodenticides: kills rodents RoundUp: Herbicide Raid: Insecticide D-Con: Rodenticide
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Type: Chlorinated Hydrocarbons DDT Paul Muller discovered insecticide. Won Nobel Prize in 1948. Killed everything ranoff into water (fish). Bioaccumulation: fat soluble.
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DDT Effects Slow degradation..DDT interfered with Ca+ uptakes in birds laid weak shells. Both Fish Eaters! Broken eggs led to decrease in pop. size!
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DDT Side Notes Neurotoxin: opens insect Na+ channels spasms/death. Resistant mutants
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Human Effects Genotoxicity Carcinogen? Endocrine disruption Diabetes Miscarriages
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Locally! Montrose Chemical on Normandy in Carson Dumped into sewers emptied into White Point Palos Verdes White croaker fish! Daily breeze 2008: seals higher concentrations of DDT
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Rachel Carson: Silent Spring 1960’s Showed effects of biomagnification and bioamplification of DDT. Showed public the effects of env. pollution.
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Type: Organophosphates Malathion: Insecticide Used to combat Med. fruit fly in CA. Sprayed in San Bernardino. Treats head lice and scabies! Med Fly
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Why Use Pesticides? 1) Saves lives. Ex: Malaria: a protozoan parasite infects RBCs. Passed on by mosquitoes. Kills 1-3 mill/yr. Found in humid areas. Malaria
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Why Use Pesticides? 2) Increases food supplies 3) Increase money profits for farmers.
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Case Study: Myxomatosis Virus introduced to rabbits in Australia. Pops went from 600-100 mill. Now, only 50% effective. Intro’d another virus in ‘96
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Why Use Pesticides? 4) Work faster and better than alternatives. You Can Then Eat the Dead Bugs!
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Negatives 1) Pesticide Treadmill: All pests that are not killed reproduce make resistance offpsring. Now, farmer has to use more pesticide or switch to another brand.
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Negatives 2) Toxic to Non- target species Pesticides do not stay put (rain/wind runoff). Affects ALL orgs of ecosystem. Red- Tailed Hawk CA King Snake
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Negatives 3) Human Sickness Acute (short-term) exposure: bleeding, vomiting. Chronic (long-term) exposure: nerve problems, brain damage, cancer, birth defects.
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Pesticide Regulation Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), 1947. All pesticide use must be approved 1 st by the EPA. Pesticide makers must test for toxicity.
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Integrated Pest Management Using a combo of pest control strategies: chemicals and alternatives. +
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Alternatives to Pesticides 1) Introduce natural predators of bug: ex: ladybug and aphid 2) Put up smells that attract bugs away from crops (pheromones) 3) Spray boiling H 2 O Chrysanthemums
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Alternatives 4) Genetically modify plants to be resistant to pests (GMO’s) Frost-Resistant Strawberries (from fish gene)? Broccoflower Tangelo: grapefruit and tangerine
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Case Study: BT Insecticide Gene BT = protein found in natural soil bacteria, Bacillus thuringensis. Disrupts guts of insects Not toxic to humans or animals BT gene placed in corn to protect against corn borer.
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BT gene placed in corn to protect against corn borer
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Broccoflower
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Tangelo = Tang. And Grapefruit
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Advantages of GMO’s Less pesticides are used Higher nutritional content Possible vaccine delivery Less water used (on irrigation) Less inorganic fertilizers are used Enough food to feed the world!
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Disadvantages of GMO’s Cross pollination with wild species reduces biodiversity Emergence of superbugs Fear of unknown allergens Centralized control of food production Poor farmers can’t afford GM patented seeds
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