It lives in soils around the world. It acts as an effective natural insecticide. And it regularly wins battles against moth and caterpillar species 20,000 times its size.
It’s called bacillus thuringiensis, or Bt, and it’s one of the most versatile tools in modern agriculture. It is widely used around the world in liquid form or as a biotech trait in seed.
Measuring one micrometre (one thousandth of a millimetre) in size, the Bt bacterium has been helping farmers and gardeners battle insect pests for the past century.
Measuring one micrometre (one thousandth of a millimetre) in size, the Bt bacterium has been helping farmers and gardeners battle insect pests for the past century.
Corn borers caused so much damage to corn during the 1990s, they earned the label 'billion dollar pest'
One of Bt’s virtues is that it exists naturally in soils around the world. Another is its insecticidal properties. First discovered in 1901 in Japan, and again in 1911 in Germany, these properties have made Bt an indispensable crop protection tool for 100 years.
One of Bt’s virtues is that it exists naturally in soils around the world. Another is its insecticidal properties. First discovered in 1901 in Japan, and again in 1911 in Germany, these properties have made Bt an indispensable crop protection tool for 100 years.
For the past 50 years, Bt has been used by organic farmers as an approved microbial pest control agent (MCPA),a in a liquid spray form. Four individual strainsb have proven especially useful, making up the bulk of those used in organic farming. Overall, thousands of strains of Bt have been identified, and at least 200 of them have known insecticidal properties.
Conventional farmers are also finding value in using Bt. Starting in 1995, seeds genetically modified with the Bt protein have been rapidly adopted around the world.
These biotech traits are environmentally beneficial, as they help reduce the spraying of topical insecticides1, and they only target the pests that are eating crops.
Insects like the European corn borer, the pink bollworm, and the corn rootworm have done billions of dollars of damage to many different crops over the past couple decades, in every agricultural region on the planet. In some regions, as much as 40% of the crop is lost to pests.d
Similar in appearance to a caterpillar, these borers and worms all have one trait in common: an alkaline digestive tract that makes them susceptible to a specific protein produced by Bt. This specificity means Bt is harmless to other beneficial insects, as well as humans and domesticated animals.
The corn rootworm also inflicts a substantial amount of damage to crops annually.
Many bacteria produce spores to preserve their genetic material, a process known as sporulation. During this process, Bt produces protein crystals, known as Cry proteins. These crystals target the digestive tract of lepidoptera moths and caterpillars, providing a very precise and targeted form of insect control.
This precision means that no known side effects exist from exposure by humans, beneficial insects, or domesticated animals like livestock and pets. Current Bt crops include soybeans, corn, cotton, and brinjal (eggplant).
This precision means that no known side effects exist from exposure by humans, beneficial insects, or domesticated animals like livestock and pets. Current Bt crops include soybeans, corn, cotton, and brinjal (eggplant).
Since 1995, Bt has become one of the most common GM seed traits around the world. Bt corn was first introduced in the U.S. in 1995, followed shortly afterward by Bt cotton. More recently, Bt soybeans (2010 in Brazil) and Bt brinjal (2014 in Bangladesh) have found success fighting insect pests. In each case, farmers have embraced the arrival of Bt seed technology, because of its targeted effectiveness and the fact that they can reduce their insecticide applications in the field.
Bt field corn has nearly two decades of success in the U.S. The European corn borer and the corn rootworm regularly devastated corn crops, until Bt corn came along. Seed companies keep multiple generations of Bt products in their research and development pipelines, due to the value farmers have found in them. Keeping ahead of research and development also helps address the possibility that a pest may develop resistance to a specific Bt insecticide.
Bt crops have been popular in Brazil over the past 20 years. By the end of 2015, Brazilian farmers had planted more than 12 million hectares of Bt soybeans and 11 million hectares of Bt maize. This summer, the country approved a Bt version of sugarcane, to provide relief to farmers who currently suffer roughly $1.5 billion worth of damage from the sugarcane borer each year.
India grows more Bt cotton than any country in the world. Before its introduction in 2002, the pink bollworm wreaked havoc on Indian cotton fields. Since then, the nation’s cotton growers have rapidly adopted cotton seeds with Bt traits. In addition to growing healthier crops, farmers have reduced topical pesticide use by more than 60%.
Another Bt cotton success story is Australia, where it has been effective at fighting the cotton bollworm and the Australian bollworm since 1996. Over the past 20 years, Bt cotton has allowed farmers to reduce insecticide use, leading to reduced fuel use, as farmers needed fewer tractor passes across their fields.
The first approved Bt food crop was Bt brinjal in 2013 in Bangladesh. Known in some parts of the world as eggplant, brinjal is a staple food crop in this region, and it is particularly susceptible to the fruit and shoot borer. With a long growing season, and an insect pest that can survive the winter, brinjal faces major pest pressures. In the past, farmers experienced regular crop losses, and were forced to rely on large quantities of topical insecticides. Since the introduction of Bt brinjal, however, they have reduced their pesticide use by more than 70 percent.
By the end of 2016, roughly 23.1 million hectares of land worldwide were planted with Bt crops.e
By the end of 2016, roughly 23.1 million hectares of land worldwide were planted with Bt crops.e
Used by organic and conventional farmers. No residual negative effects.
And nearly a century of effective use in crop protection.
In every instance, in every region, for every crop, the introduction of Bt biotech traits has meant less topical insecticide sprayed, less crop damage from insect pests, and little to no collateral damage to beneficial insects and animals.
Much of the credit goes to the farmers themselves, who are charged with proper use of the product. As with any seed, it’s important to plant what is known as “refuge” when using Bt crops. This means a fixed percentage of every field is planted without the Bt biotech trait, to ensure some targeted insect pests survive, thus slowing the rate at which resistance to Bt occurs in those pests.
Much of the credit goes to the farmers themselves, who are charged with proper use of the product. As with any seed, it’s important to plant what is known as “refuge” when using Bt crops. This means a fixed percentage of every field is planted without the Bt biotech trait, to ensure some targeted insect pests survive, thus slowing the rate at which resistance to Bt occurs in those pests.
Overall, Bt has been an undeniable success. Organic farmers have been using it for 50 years, and conventional farmers for the past 20. This widespread use and success has provided a model for modern agriculture to follow. And it has provided hope to the rest of us: hope that we can continue moving forward with technology, while giving back to the planet.
a,b http://www.bt.ucsd.edu/organic_farming.html
chttp://www.croplifeamerica.org/facts/
dhttps://geneticliteracyproject.org/2017/07/19/gmo-insect-resistant-sugarcane-approval-brazilian-farmers-poised-reap-benefits-nations-strong-biotech-pipeline/
ehttp://www.isaaa.org/resources/publications/pocketk/6/default.asp
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