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Boll weevil trap. Insect pheromone trap, used to control the boll weevil (Anthonomous grandis), an important pest of cotton (Gossypium sp.). The trap mimics the weevil's own chemical attractant, or pheromone. The scent draws in weevils from the surrounding crop fields. The weevils crawl into the trap, where they are killed by an insecticide. Photographed in the southern USA. (KEYSTONE/SCIENCE PHOTO LIBRARY/DEBRA FERGUSON/AGSTOCKUSA)