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Description: Insects, fungi, viruses, rodents, and weeds that eat or compete with our crops have taken advantage of the ways we cluster food plants into agricultural fields Pest = any organism that damages valuable crops Bigger problem in monoculture Weed = any plant that competes with crops Pesticides = poisons that target pest organisms Insecticides = target insects Herbicides = target plants Fungicides = target fungi 91% of pesticide sales are for agricultural purposes 85% of pesticides sold in Canada are herbidices Usefulness tends to decline with time as pests evolve resistance to pesticides Small fraction of insects and microbes have genes that confer some degree of immunity to a given pesticide If an insect survives pesticide, resistance is passed through their genes to insect offspring Evolutionary arms race: chemists increase chemical toxicity to compete with resistant pests Picture Stats: Views: 271 Filesize: 168.01kB Height: 517 Width: 1290 Source: https://biology-forums.com/index.php?action=gallery;sa=view;id=35747 |