Articles

New study shows unanticipated negative impact of Bt insecticidal crop on beneficial insect. Report: Claire Robinson

A study from 2017 reported that most GM Bt insecticidal maize varieties lost their ability to control the fall armyworm pest within three years of introduction in Brazil, as the pest became resistant to the Bt insecticidal toxin in the plants. The same pattern of rapidly evolved pest resistance has been found in Argentina, Puerto Rico, and the United States.

Now a newly published open access study shows another mechanism through which Bt insecticidal maize crops may be failing. The Bt toxins ("Cry proteins") in Bt maize ingested by the fall armyworm pest are transferred to a natural enemy of the armyworm, the predatory stink bug Podisus nigrispinus (Dallas) – where they cause harmful changes in the predator insect's midgut cells. The authors believe that these changes could negatively impact the predator insects' fitness.