Environmental Science 1021F/G Lecture Notes - Lecture 7: Crop Rotation, Pyrethrum, Rodenticide
20 Mar 2016
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Pest: unwanted organism that interferes with human activities; subjective: a weed is a plant whose virtues have not yet been discovered . The pests that we do try to control; 100 species (1%) cause 90% of the damage: because the lack of diversity in food, doesn"t mean it only affects 100 species, non-target organism: affected but not targeted. Disturbs predator-prey cycle in natural ecosystems and polyculture: take away predators food source. 1: herbicides disrupts plant growth and metabolism, fungicide, rodenticides. Before pesticides , rotenone isolated from plants. Second generation: synthetic organic compound (eg. ddt, broad spectrum :roundup.
