Bacterium still a major source of crop pesticide

Excerpt from the April 30, 1966, issue of Science News

Bt peanut plants

SHIELDED  The bacteria Bacillus thuringiensis, Bt, make a natural insecticide that kills pest larvae chowing down on crops. Today, plants are genetically engineered to produce the bacterial toxin. Lesser cornstalk borer larvae can ravage a peanut plant (above, right), but a plant with Bt genes kills hungry pests, protecting the plant (left; dead larva visible to right of plant).

Herb Pilcher/USDA Agricultural Research Service

Bacterium effective when dusted on plants — The successful agent for destroying pesty insects, the microscopic bacterium, Bacillus thuringiensis, is most effective when it is dusted onto tobacco or other plants…. The bacteria are now recommended for use against tobacco budworms and hornworms. From known results …. they look promising as biological control agents. — Science News, April 30, 1966


Bacillus thuringiensis, or Bt, is still used to combat agricultural pests. Different strains of the bacterium target different insects; one strain can even kill mosquito larvae in water. Organic farmers dust or spray Bt on crops and consider it a natural insecticide. In conventional farming, Bt DNA is often inserted into a plant’s genome, creating genetically modified crops that make their own pesticide (SN: 2/6/16, p. 22). In 2015, 81 percent of U.S. corn and 84 percent of U.S. upland cotton contained Bt genes.

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