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Bt cotton cuts pesticide poisoning

3086374903_efccb70fa8_m.jpgOver the past ten years that farmers in India have been planting Bt cotton – a transgenic variety containing genes from the soil bacterium Bacillus thuringiensis making it pest resistant – pesticide use has been cut by at least half, a new study shows.

The research also found that the use of Bt cotton helps to avoid at least 2.4 million cases of pesticide poisoning in Indian farmers each year, saving US$14 million in annual health costs. (See Nature’s previous coverage of Bt cotton uptake in India here.)

The study on the economic and environmental of Bt cotton is the most accurate to date and the only long term survey of Bt cotton farmers in a developing country.

Previous studies have suggested that farmers planting Bt cotton use less pesticides. But these older studies did not establish a causal link and few quantified the environmental, economic and health costs and benefits.

The current study, published online in the journal Ecological Economics, surveyed Indian cotton farmers between 2002 and 2008. India is now the world’s biggest producer of Bt cotton with an estimated 23.2 million acres planting in 2010. Farmers were asked to provide agronomic, socio-economic and health data, including details of pesticide use and frequency and type of pesticide poisonings such as eye and skin irritations. Farmers who suffered pesticide poisoning provided details about heath treatment costs and costs associated with lost labour days. The survey was repeated every two years.

“The results demonstrate that Bt cotton has notably reduced the incidence of pesticide poisoning among small holder farmers in India,” the study says.

Public debates about transgenic crops should focus more on the health and environmental benefits which can be “substantial” and not just the risks, the study adds.

Kouser, S. & Qaim, M. Ecol. Econ. (2011)

Picture credit:cliff1066 via Flickr under Creative Commons


  1. Report this comment

    Tricia Lyman said:

    Did this or any related study mention rates of soil depletion nitrogen usage in BT vs. non-BT or the reduction (or overproduction) of microbial biomass (if any) in BT crops?

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    GMKnow said:

    Poisoning via pesticide application may be down, but let’s not forget that the BT pesticide is incorporated into every cell of the crop. It cotton seed is converted to oil, or if BT corn, soy or canola are eaten, every bite contains pesticide. Whether it’s via spray or eaten, I don’t think any of these BT GMO crops are worth the health risks.

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    Seema said:

    There has been a lot of propaganda on Bt Cotton and the benefits of its usage on farmers’ lives. There has been a lot of promotion by Monsanto on how the productivity of cotton has increased and the use of pesticides has decreased. Although Bt Cotton might be bringing prosperity to some villages by increasing production, its far reaching effects are not yet known and neither have been researched properly.

    Couple of things we think need some debate and thought before we go all gaga about Bt Cotton:

    1. It’s against nature – altering genetics is definitely not normal. Nature is in perfect balance and disturbing one part may have unknown effects on balance in nature. And there is no way if knowing what this genetic mix up will cause in future.

    2. Some scientists say that the insects (ballworms) may become resistant to Bt in about 10 crop generations. Due to this reason, there was government’s directive to use Bt Cotton in only 20% of area but there is lack of enforcement in this.

    3. There is lack of research and collation of data as to exactly how much productivity increases because of Bt Cotton. There still seems to be high suicide rates among cotton farmers even in states that have adopted Bt Cotton.

    4. In November 2009, Monsanto scientists found that the pink bollworm had become resistant to Bt cotton in parts of Gujarat, India. In four regions, Amreli, Bhavnagar, Junagarh and Rajkot the crop is no longer effective at killing the pests. This was the first instance of Bt resistance that was confirmed by Monsanto anywhere in the world. Monsanto confirmed field resistance of the worm to the Cry1Ac first generation Bollgard cotton, which expresses a single Bt gene. It’s response? Ask the farmers to move on to the new Bt Cotton version, which has yet another genetic mutation.

    5. Several studies have documented surges in “sucking pests” (which are not affected by Bt toxins) within a few years of adoption of Bt cotton. In China the main problem has been with mirids, which have in some cases "completely eroded all benefits from Bt cotton cultivation”

    Seema (

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    Jen Hutchinson said:

    Please see the following which shows BT Cotton as:

    1. Requiring more pesticides

    “Why Pesticides Continue to Haunt BT Cotton”

    2. Harmful to the environment- and to farm yields (due to pests, and soil nutrient depletion). In other words, the bt cotton is actually detrimental to farmers livlihoods (see suiciide story below for effects of bt crop on soil/harvest)

    “Agriculture issues on India Together

    China: Study says Bt Cotton Is Harmful For Environment"

    3. Linked to ‘cause’ of the unfortunate suicides due to farmers’ indebtedness due to crop failures

    “The bt Cotton Killing Fields”

    “Coker-312 (initially from Monsanto) showed high susceptibility to attacks by sucking pests like jassids and thrips. The thrips disperse within plant cells, while jassids suck the sap as they multiply under a leaf’s surface, forcing the plant to draw more nutrients from the soil, aggravating the soil’s nutritional deficiency.

    Another characteristic of Bt cotton that depletes the soil is that the bolls come to fruition simultaneously, draining the soil all at once. In a region like Vidarbha, plants wilt in two or three days. “It is like drawing blood from anemic woman.”

    “If such a technology mismatch continues, soil health and farmers’ economy will take a further hit,” a top ICAR scientist with years of experience in cotton research was reported saying 5."

    4. Monsanto’s own admission that bt cotton has been a failure (which is eluded to in your Post, I believe).

    “Bt cotton has failed admits Monsanto”

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    Katydid said:

    I have such a bad reaction to cotton cloths, sheets, towels, etc. I can only use cotton that is 10 years old or older. I thought it was something they did to cotton in China, but the Cloths made in the USA are just as bad. BT cotton should be outlawed.

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