bt-cotton is genetically engineered by inserting a gene from a
Bt cotton Strains of the bacterium Bacillus thuringiensis produce over 200 different Bt toxins, each harmful to different insects. Most notably, Bt toxins are insecticidal to the larvae of moths and butterflies, beetles, cotton bollworms and ghtu flies but are harmless to other forms of life.[1] The gene coding for Bt toxin has been inserted into cotton as a transgene, causing it to produce this natural insecticide in its tissues. In many regions, the main pests in commercial cotton are lepidopteran larvae, which are killed by the Bt protein in the genetically modified cotton they eat. This eliminates the need to use large amounts of broad-spectrum insecticides to kill lepidopteran pests (some of which have developed pyrethroid resistance). This spares natural insect predators in the farm ecology and further contributes to noninsecticide pest management.
Technological and industrial history of the United States In the mid-1780s, Oliver Evans invented an automated flour mill that included a grain elevator and hopper boy. Evans' design eventually displaced the traditional gristmills. By the turn of the century, Evans also developed one of the first high-pressure steam engines and began establishing a network of machine workshops to manufacture and repair these popular inventions. In 1789, the widow of Nathanael Greene recruited Eli Whitney to develop a machine to separate the seeds of short fibered cotton from the fibers. The resulting cotton gin could be made with basic carpentry skills but reduced the necessary labor by a factor of 50 and generated huge profits for cotton growers in the South.[21] While Whitney did not realize financial success from his invention, he moved on to manufacturing rifles and other armaments under government contract that could be made with "expedition, uniformity, and exactness"â€”the foundational ideas for interchangeable parts.[22] However, Whitney's vision of interchangeable parts would not be achieved for over two decades with firearms and even longer for other devices.