Are there surprising ecological effects of genetically modified plants?

06.10.2017

GenØk Senior Scientist Thomas Bøhn has a new publication in Frontiers in Environmental Science (open access)!

Article: Complex outcomes from insect and weed control with transgenic plants: Ecological surprises?

Genetically modified (GM) plants have mainly been used to avoid: 1) insect pests, and 2) weeds in maize, soybean, canola and cotton. The two main traits used are plant-produced toxins (Bt-toxins), or tolerance to spraying with herbicides. A new article from GenØk describes the ecological effects of these proposed and tested agricultural solution in a sustainability context.

The article concludes that:

  1. The use of Bt-toxins may lead to resistance development, the example of the Busseola fusca in South Africa is described in detail. Observed benefits with Bt-maize, like reduced spraying with pesticides did not last for long. In general, the response to resistance in insects has led to ‘stacking’ of different Bt-toxins (up to 6) in the same plant.
  2. The use of Bt-cotton in China led to several positive effects on a landscape level. Pest insects were successfully targeted by Bt-toxins with an overall reduction of pesticide use as well as reduced harm on cotton and other crops. However, again, these benefits did not last. Mirid bugs, a secondary pest that is less sensitive to Bt-toxins, took over the role as the dominant pest. Mirid bugs could use the GM Bt-cotton as a host plant and thus spread over large areas, harming cotton but also other valuable plants in the landscape.
  3. The monarch butterfly with its fascinating migration from Mexico, thousands of kilometers through the US, is threatened. The cause is found in the extreme weed control based on herbicides. Herbicide tolerant plants are sprayed several times in the growing season and milkweed, the main host plant for the monarch, is near extinct in GM soy and maize fields that cover vast areas of land.

Use this link if you want to read the entire article

Bøhn, T. and Lövei, G.L. (2017). ”Complex outcomes from insect and weed control with transgenic plants: ecological surprises?”, Frontiers in Environmental Science 5: 1-8. https://doi.org/10.3389/fenvs.2017.00060 (Open access)

Photo: AdobeStock #69981160