Environmental Science 1021F/G Final: Environ Final.docx
19 Apr 2013
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Document Summary
Pests and pesticides: pest unwanted organism that interferes with human activities; subjective. Insecticides block reproduction, airways, nervous system: herbicides disrupt plant growth and metabolism, fungicides, rodenticides. Crop rotation, vary planting times, plant diversity, hedgerows: based on plants natural instincts . Synthetic organic compounds (eg ddt), broad- and narrow-spectrum, persistence reduction, some natural. Saves human lives malaria, bubonic plague, typhus. Increase food supplies and profits; lower costs: work faster and better than alternatives, health risk *may* be insignificant compared to benefits. 3000-6000 death/yr (epa: new pesticides are safer and used at lower rates than older pesticides. What are the true costs: genetic resistance insects and plants, kill non-target organisms, incl. natural predators. Harm wildlife: pesticide movement, human health threat; 20,000 40,000 deaths, use reduced without yield decrease. Still 6% decrease in yield loss to pests. Some based on biomimicry, part of integrated pest management (ipm: change cultivation practices (cultural, biological pest control. Plant, irrigate, fertilize, apply pest control, harvest.
