Figure: A new major meta-analysis has found that Bt corn does not damage nontarget organisms. (Photo by Preston Keres, USDA)

Steve Naranjo from the U.S. Department of Agriculture Agricultural Research Service (USDA ARS) and entomologists from Agrocscope in Switzerland have conducted the largest meta-analysis of the impact of genetically modified (GM) Bt corn on nontarget insect pests and other organisms.

Bt corn is corn that has been genetically modified to produce proteins from the bacterium Bacillus thuringiensis (Bt) to control corn borers, corn rootworms, and other major pests of corn. The first Bt corn was approved in 1996 and critics have suggested that it destroys beneficial insects or other non-targeted organisms. The study, now published in Environmental Evidence, reveals that Bt corn has little impact on nontarget insects and other organisms, especially compared to growing conventional corn.

One of the issues with assessments of possible nontarget organism damage by Bt corn has been that each study was limited in scope, environment, or size. The paper's three authors have made up for these shortfalls by systematically pulling together data from studies in 12 bibliographic databases, 17 specialized web pages, and the reference sections of 78 review articles that all met the highest standards for research quality.

Naranjo and entomologists Joerg Romeis and Michael Meissle with Agroscope found that this massive aggregation of data showed Bt corn had no negative effects on most invertebrate groups including ladybeetles, flower bugs, and lacewings. Populations of Braconidae insects, which are parasitoid wasps that prey on corn borers, were reduced with Bt corn.

For more details, read the news article on the USDA ARS website.