Indirect side-effects of the cultivation of genetically modified plants

Mar 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: Like eating fish? It's time to start caring where it comes from

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

add to favorites email to friend print save as pdf

Related Stories

New bacteria toxins against resistant insect pests

Oct 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, us ...

ARS Survey Helps Growers Track Two Key Cotton Pests

Dec 01, 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

Aug 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

Nestling birds struggle in noisy environments

23 hours ago

Unable to fly, nestling birds depend on their parents for both food and protection: vocal communication between parents and offspring helps young birds to determine when they should beg for food and when they should crouch ...

The secret life of the sea trout

Oct 29, 2014

Jan G. Davidsen and his graduate students are spies. They use listening stations and special tags they attach to their subjects to track their movements. They follow their subjects winter and summer, day ...

Giant tortoises gain a foothold on a Galapagos Island

Oct 28, 2014

A population of endangered giant tortoises, which once dwindled to just over a dozen, has recovered on the Galapagos island of Española, a finding described as "a true story of success and hope in conservation" ...

Fish "personality" linked to vulnerability to angling

Oct 28, 2014

Individual differences in moving activity in a novel environment are linked to individual differences in vulnerability to angling, according to an experimental study completed at the University of Eastern Finland and the ...

User comments : 0

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.