Bacillus thuringiensis (Bt) is a naturally occurring soil bacterium that we use in some of our corn and cotton seed products to provide protection from damaging insects. While all of our Bt crops continue to be highly effective tools for farmers, our research team constantly reviews and monitors individual fields for resistance. We have expanded programs to monitor corn rootworms in the United States (2011 – Ongoing) and pink bollworms in cotton in India (2009 – Ongoing).
Since the advent of farming, people have searched for ways to save their crops from insect pests. Even ancient farmers were known to have collected seeds from high-yielding plants in the hope of producing crops the next year that could withstand insect infestation.
Bt, or Bacillus thuringiensis, is a modern solution to insect control.
Bacillus thuringiensis (Bt) is a bacterium that occurs naturally in the soil and produces proteins that kill certain insects. Through biotechnology, scientists can use these naturally occurring Bt proteins to develop insect-protected crops that help farmers protect against insect damage and destruction. When targeted insects eat the plant containing the protein, they ultimately die; but Bt is not harmful to humans, other mammals, birds, fish or beneficial insects.
Insect resistance to Bt proteins is natural and expected.
In any insect population, a small number of insects already exist that are tolerant of – or resistant to – certain Bt proteins. Over time, and especially with particular farming practices, it is possible that too many insects in a field could develop a tolerance to a Bt protein and cause significant damage or destruction.
Farmers can help prevent insect resistance through Insect Resistance Management (IRM) practices.
Farmers who choose to grow a Bt crop must plant a “refuge” – a block or strip of the same crop that does not contain a Bt trait, or the non-Bt refuge seed can be included in an EPA-approved seed blend product, which we refer to as “Refuge in the Bag” or RIB. The insects from the refuge are not exposed to the Bt protein and susceptible insects will survive, potentially mating with resistant insects from the neighboring field. This practice is known as Insect Resistance Management.
There are two instances where Monsanto entomologists have expanded their monitoring and review of insects for potential resistance.
- Corn Rootworm, United States (2011 – ongoing)
In 2011, entomologists at Monsanto became aware of heavy rootworm infestation in isolated fields across the Corn Belt where there was a long history of corn-on-corn plantings. Our team continues to work closely with farmers to implement best management practices on those fields where resistance is suspected, and farmers are seeing excellent results. Extensive information about the corn rootworm and our ongoing efforts are available in different section of our web site: Corn Rootworm Management
- Pink Bollworm in Cotton, India (2009 – Ongoing)
In 2009, our entomologists detected and ultimately confirmed pink bollworm resistance to Bt cotton (Bollgard I) in Western India; no pink bollworm resistance was ever confirmed outside this area. In 2006, we introduced a new cotton seed that contained two different Bt proteins – providing additional and more robust protection against the bollworm. This product – Bollgard II – has replaced Bollgard I in all of our cotton seed markets, and no instances of insect resistance have been observed.
Monsanto scientists are continually researching and developing insect protection products and recommendations for farmers.
Monsanto scientists continually research causes of Bt resistance, as well as conduct research and development of other genes that could help control insect infestation. In addition, we regularly evaluate the need for updating our crop management recommendations as new scientific data becomes available.