... control of pests probably began with poisonous plant compounds. In the 18th and 19th centuries, farmers ground up certain plants that were toxic to insects or rodents--plants such as chrysanthemums or tobacco. The plant "soup" was then applied directly to either the crops or the pests. Chemists later discovered that they could extract the toxic compounds from these poisonous plants ... ...

• Word Count: 2580
• Approx Pages: 10
• Grade Level: Undergraduate