History of Bt
What is Bt
how does Bt work
Bt Animal safety
What is a Bt crystal
Genetically Modified Organisms
Bt Transgenic Crop
Bt cotton
Bt crop refuge
Synthetic Pesticide
Organic farming
Bt vector control
Pest resistance

Bt GM (genetically modified) crops

Corn rootwormSince 1996 plants have been modified with short sequences of genes from Bt to express the crystal protein Bt makes. With this method, plants themselves can produce the proteins and protect themselves from insects without any external Bt and/or synthetic pesticide sprays. In 1999, 29 million acres of Bt corn, potato and cotton were grown globally. It has been estimated that by using Bt protected cotton, the United States was able to save approximately $92 million.

Bt GM crops are protected specifically against European corn borer, southwestern corn borer, tobacco budworm, cotton bollworm, pink bollworm and the Colorado potato beetle. Other benefits attributed to using Bt include:

  • Reduced environmental impacts from pesticides – When the plants are producing the toxins in their tissues there is no need to spray synthetic pesticides or apply Bt mixtures topically.
  • Increased opportunity for beneficial insects – Bt proteins will not kill beneficial insects.
  • Reduced pesticide exposure to farm workers and non-target organisms.

Potential risks to using Bt:

  • Invasiveness – Genetic modifications, through traditional breeding or by genetic engineering can potentially change the organism to become invasive. Few introduced organisms become invasive, yet it’s a concern for the users.
  • Resistance to Bt - The biggest potential risk to using Bt-crops is resistance. Farmers have taken many steps to help prevent resistance.
  • Cross-contamination of genes - Although unproven, genes from GM crops can potentially introduce the new genes to native species.