Australia's Cane Toad Problem

This had serious economic consequences for sugar cane farmers. Modern pesticides were not developed until the 1940s, so farmers had to use what was available at the time. Chemicals like arsenic and copper were used, but these were not only expensive but also stayed in the environment and were poisonous to people, plants and animals. It was generally acknowledged by government, farmers and scientists that cheaper and safer methods of pest control had to be found. B A promising replacement for copper and arsenic was the use of biological control. Farmers already used some forms of biological pest control in the form of predatory and parasitic wasps and flies, insect-eating birds, and plants from different regions or countries to control pests. Common practice was to release these introduced agents into new environments, the expectation being that they would destroy resident pests. Some species of toad already had successful records as agents of biological control in gardens. For example, in 19th-century France, toads were sold to gardeners at markets in Paris to eat insect pests in their gardens. In the early 20th century French sugar cane farmers first took giant toads from South America to control pests in their…