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DO NOW Form groups. Download ch.16 Notes Download: Chapter Presentations (if you don’t have it saved). 1: blue – 2 2: green - 2 3: salmon - 2 4: purple - 3 5: white - 3 6: red - 2 7: yellow - 3 8: orange - 2. Desert Locust Ranges. Pests and Pest Control. The need for pest control
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DO NOW Form groups. Download ch.16 Notes Download: Chapter Presentations (if you don’t have it saved) 1: blue – 2 2: green - 2 3: salmon - 2 4: purple - 3 5: white - 3 6: red - 2 7: yellow - 3 8: orange - 2
Pests and Pest Control • The need for pest control • Promises and problems of the chemical approach • Alternative pest control methods • Socioeconomic issues in pest management • Pesticides and policy
The Need for Pest Control: Defining Pests • Any organism that has a negative effect on human health or economics • Any organism that is noxious, destructive, or troublesome • Plants or animals (see Fig. 16-2) • Formosan termite • Fire ants • Aedes mosquito • Medfly
Pest Control Purposes • Protect our food • Protect our health • Convenience
Different Philosophies of Pest Control • Chemical technology • Use of chemicals to kill large numbers of the pest • Short-term protection • Environmental and health consequences
Different Philosophies of Pest Control • Ecological pest management • Control based on pest life cycle and ecology • Control agent may be an organism or chemical (more on next slide)
Different Philosophies of Pest Control • Specific to pest and/or manipulate a part of the ecosystem • Emphasizes protection from pest • Integrated pest management: “using all suitable methods – chemical and ecological – in a way that brings about long-term management of pest populations and minimal environmental impact.”
Promises and Problems of the Chemical Approach • Development of chemical pesticides and their successes • Problems stemming from chemical pesticide use
Development of Chemical Pesticides • First-generation pesticides (inorganic) • First attempt at chemical technology • Toxic to humans and agricultural plants • Pests developed resistance
Development of Chemical Pesticides • Second-generation pesticides • Used after WW II • Organic chemical • Toxic to humans and agricultural plants • Pests developed resistance
The DDT Story • DDT: the magic bullet • Extremely toxic to insects; seemed nontoxic to humans and other mammals • Cheap • Broad-spectrum and persistent (more next slide)
The DDT Story • DDT: the magic bullet • Effective for disease prevention (typhus fever, malaria) • Expanded agricultural production • Paul Muller awarded Nobel prize in 1948
Problems Stemming from Chemical Pesticide Use • Development of resistance by pests • Resurgences and secondary pest outbreaks • Adverse environmental and human health effects
Resistance • Chemical pesticides lose effectiveness • Resistant pest populations produce next generations
Resurgence and Secondary Outbreaks • Resurgences: after “eliminating” a pest, its population rebounds in even higher numbers than previous levels. • Secondary outbreaks: outbreaks of species’ populations that were not previously at pest levels.
The Bugs Are Coming! Time Magazine, July 12, 1976, page 38
Human Health Effects • Cancer, dermatitis, neurological disorder, birth defects, sterility, endocrine system disruption, immune system depression. • Agricultural workers suffer acute poisoning during pesticide application.
Human Health Effects • Aerial spraying and dumping bring pesticides in contact with families and children. • Soldiers exposed to agent orange in Vietnam suffered high rates of cancer and other diseases.
Environmental Effects • DDT led to the decline in populations of several bird species • Bald eagle • Peregrine falcon • Bioaccumulation • Biomagnification
Nonpersistent Pesticides • Substitutes for banned pesticides • Breakdown after a few weeks • Can still be harmful because of: • Toxicity • Dosage • Location
Alternative Pest Control Methods • Cultural control • Control by natural enemies • Genetic control • Natural chemical control
Genetic Control • Plants or animals are bred to be resistant to the attack of pests. • Chemical barriers. • Physical barriers.
Control Using Natural Enemies
Genetic Control • Chemical barriers, e.g., Hessian fly • Physical barriers, e.g., sticky glandular hairs • Sterile males are released into pest population, e.g., botfly larvae • Genetic engineering, e.g., Bt Bacillus thuringiensis - a bacterium that produces a protein killing larvae of many insect pests.
Natural Chemical Control • A volatile chemical produced by the opposite sex of a species which alters the reproductive behavior of the opposite sex. • Perfumes • Colognes • After shave • Natural body odors
Natural Chemical Control • Manipulation of pests’ hormones or pheromones to disrupt the life cycle. • Japanese beetle trap.
Socioeconomic Issues of Pest Management • Pressures to use pesticides • Integrated pest management • Organically grown food
Integrated Pest Management (IPM) • An approach to controlling pest populations using all suitable methods - chemical and ecological - in a way that brings about long-term management of pest populations and also has minimal environmental impact
Organically Grown Food • Employ traditional farming methods • Crop diversity • Lower crop yields and expenses • Richer field and orchard soil • Sales of organics now a $31 billion enterprise in the U.S. alone. • USDA Organic: Organic Foods Protection Act of 1990
Three Concerns • Pesticides evaluated for intended use and impacts on human health and the environment. • Protection and proper training of those who work with pesticides. • Public protection from risks of pesticide residues on food products.