Indirect side-effects of the cultivation of genetically modified plants

March 13, 2013

Genetically modified Bt cotton plants contain a poison that protects them from their most significant enemies. As a result, these plants rely less on their own defence system. This benefits other pests, such as aphids. These insights stem from a study supported by the Swiss National Science Foundation (SNSF).

Only ten years ago, genetically modified cotton grew on 12% of all fields – today it is cultivated on over 80% of all cotton fields around the world. Bt cotton contains a gene of , a species of . The plant uses it to produce a poison whose effects are fatal to the principal – voracious caterpillars. However, certain types of bugs and other pests begin to spread across cotton fields instead, as is the case in China. The decline in the use of may be partly responsible for this development, but it is probably not the only factor.

Spoiling their appetites

A team of researchers led by Jörg Romeis from the Agroscope Reckenholz-Tänikon Research Station has now identified a biological mechanism that offers an additional explanation for the increase in new pests in Bt cotton fields. have a sophisticated defence system. When caterpillars begin to nibble on them, they form defensive substances, so-called terpenoids. This spoils the appetite of not only the caterpillars, but of many other nibblers as well.

Also helpful against bugs?

Cotton aphids generally do not cause severe agricultural damage because they succumb to their out in the open. His results are therefore not relevant to farming, says Romeis. However, he has for the first time revealed an indirect effect of Bt cotton: the killing of the caterpillars also affects other plant-eating insects because the plants' defence system remains inactive. Romeis now wants to investigate whether this effect is relevant to aphids only or also to the bugs that are creating problems for cotton farmers in China and in other cotton-growing regions of the world.

Explore further: Chinese researchers find Bt cotton controls pests while also promoting good bugs

More information: Hagenbucher, S. et al. (2013). Pest tradeoffs in technology: Reduced damage by caterpillars in Bt cotton benefits aphids. Proceedings of the Royal Society B. doi: 10.1098/rspb.2013.0042

Related Stories

New bacteria toxins against resistant insect pests

October 19, 2011

Toxins from Bacillus thuringiensis bacteria (Bt toxins) are used in organic and conventional farming to manage pest insects. Sprayed as pesticides or produced in genetically modified plants, Bt toxins, used in pest control ...

ARS Survey Helps Growers Track Two Key Cotton Pests

December 1, 2009

(PhysOrg.com) -- Cotton growers will be better able to keep an eye out for two common pests because of a comprehensive survey by Agricultural Research Service (ARS) scientists at College Station, Texas.

Transgenic maize is more susceptible to aphids

August 29, 2007

The environmental consequences of transgenic crops are the focus of numerous investigations, such as the one published in the journal PloS ONE, which was carried out by Cristina Faria and her colleagues, under the supervision ...

Recommended for you

Ants need work-life balance, research suggests

January 16, 2017

As humans, we constantly strive for a good work-life balance. New findings by researchers at Missouri University of Science and Technology suggest that ants, long perceived as the workaholics of the insect world, do the same.

New tools will drive greater understanding of wheat genes

January 16, 2017

Howard Hughes Medical Institute scientists have developed a much-needed genetic resource that will greatly accelerate the study of gene functions in wheat. The resource, a collection of wheat seeds with more than 10 million ...

How China is poised for marine fisheries reform

January 16, 2017

As global fish stocks continue sinking to alarmingly low levels, a joint study by marine fisheries experts from within and outside of China concluded that the country's most recent fisheries conservation plan can achieve ...

SMiLE-seq: A new technique speeds up genetics

January 16, 2017

Scientists at EPFL have developed a technique that can be a game-changer for genetics by making the characterization of DNA-binding proteins much faster, more accurate, and efficient.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.