Presentation on theme: "Pesticides. What are Pesticides? Pesticide: Any substance used for the purpose of destroying or controlling pests. Used in agriculture to protect crop."— Presentation transcript:
What are Pesticides? Pesticide: Any substance used for the purpose of destroying or controlling pests. Used in agriculture to protect crop plants Types of pesticides: PesticideWhat does it Kill InsecticideInsects HerbicidePlants (weeds) FungicideFungus AlgicideAlgae RodenticideRodents
How do pesticides work Insects: Most work through poisoning the insect Herbicides: Absorbs through the membranes Fungicides: Enters fungus through absorption
Chemical Pesticides Chemical Pesticides are Grouped into Chemical Families Organochlorines: Attack the nervous system of insects Organophosphates: Replaced organochlorides. Also a neurological pesticide. Used in nerve gases. Effective herbicide. Carbamates: Replaced organophosphates prevents nerve impulses from being transmitted causing paralysis
Chemical Pesticides Chemical Pesticides are Grouped into Chemical Families Pyrethroid pesticide: Comes from the chrysanthemum. Attacks nervous system Sulfonylurea Pesticides: Kills plants by inhibiting enzymes
Biopesticides Biopesticide: Bio = living Pesticide = killing substance Biopesticides are substances from natural sources that are used to destroy or control organisms Examples: Canola oil, baking soda
Three Classes of Biopesticides Microbial Pesticides: Microorganisms that are used to control pests. Can include beneficial bacteria, viruses, fungus and protozoans Plant-Incorporated-Protectants: Adding genetic material to plants that allow them to make the pesticide chemicals found in the beneficial organisms Biochemical Pesticides: Using chemicals produced by organisms to reduce pest populations. eg. Releasing scent chemicals to lure pests into a trap
Cost of Pesticides Health Acute (immediately) Illnesses caused by pesticides: -Skin and eye irritation -Nervous system problems -Infertility by mimic reproductive hormones Chronic (long term) Illnesses caused by pesticides: -Cancer (Leukemia) - Birth defects - Neurological Disorders (autism)
Cost of Pesticides Pesticide Drift: Occurs when pesticides are blown into unintended location by wind. Over 90% of the pesticides we apply does not reach its target pest species.
Problems with Pesticides Water Pollution: Many pesticides are persistent organic pollutants. These increase in concentration as they move up the food chain. Results in nerve damage in aquatic organisms. Biodiversity: Loss of higher trophic species due to bioaccumulation. Pollinator Decline: Pollinating insects such as bees spend a lot of time in crops. When a pesticide is sprayed for insects It kills the pollinators.
Alternatives to Pesticides 1)Using carnivorous insects to eat crop eating pest insects 2)Using genetically modified foods 3)Crop rotation. Planting corn in a wheat field which is contaminated with a pest that attacks wheat but not corn.